chromium users guide - teledyne cetac · chromium users guide chapter 2: the basics: an overview of...

Chromium

Manual Part Number 480231 Rev 0

Users Guide

COPYRIGHT

© 2016 Teledyne Technologies, Inc.

480231 Rev 0 , December, 2016

Printed in USA.

Teledyne CETAC Technologies authorizes its customers to reproduce, transmit, or store this document in its entirety, including this page, for the express purpose of installing, operating, or maintaining the product described herein.

Teledyne CETAC TechnologiesCustomer Service & Support14306 Industrial RoadOmaha, Nebraska 68144, USAPhone (800) 369-2822 (USA only)Phone +1 (402) 733-2829 Fax +1 (402) 733-1932E-mail [email protected]

REVISIONS

Teledyne CETAC Technologies strives to provide the scientific community with an unparalleled combination of effective technology and continuing value. Modular upgrades for existing instruments will continue to be a prime consideration as designs progress.

Teledyne CETAC Technologies reserves the right to revise this document and/or improve products described herein at any time without notice or obligation.

TRADEMARK ACKNOWLEDGEMENTS

Teledyne Photon Machines is a brand of Teledyne CETAC Technologies.

Windows is a registered trademark of Microsoft Corporation in the United States and other countries.

All other marks are the property of their respective owners.

Contents1 Introduction ..............................................................................................................5

Overview ..................................................................................................................................... 5Prerequisites ............................................................................................................................. 5

2 The Basics: An Overview of Chromium ...........................................................7

Chromium Start-up................................................................................................................. 7Homing Motors......................................................................................................................... 8Navigating Chromium .........................................................................................................10

Control Panels ...............................................................................................................10Main Viewport ........................................................................................................................11Optical Zoom............................................................................................................................11Video Focus ..............................................................................................................................12Place/Move Scans..................................................................................................................13View Settings ...........................................................................................................................14Troubleshooting Live Video and Tracking.................................................................16

If the Video Display Is Blank ....................................................................................16If the Video Image Does Not Move As Expected ...............................................16

Layers and Images ................................................................................................................17Saving a Video Image .................................................................................................19

Laser Control ...........................................................................................................................19FIRE Laser.......................................................................................................................19Fire Mode ........................................................................................................................20Laser Energy ..................................................................................................................20Spot Size ..........................................................................................................................20Laser Status....................................................................................................................21

View Controls ..........................................................................................................................22Gas Controls .............................................................................................................................23

Controlling the Beam Purge Gas............................................................................24Mass Flow Controllers and Gas Controls ............................................................24Gas Flow Strategies.....................................................................................................26

Scan List.....................................................................................................................................27List Editing Toolbar ....................................................................................................29Run Scans Dialog..........................................................................................................30Actions at Start of Preablation/Ablation Pass .................................................33Actions for Each Pattern ...........................................................................................33Actions at Start of Each Pattern ............................................................................33Actions at End of Each Pattern...............................................................................34Actions at End of Preablation/Ablation Pass ...................................................34Shut Off Gas Flows When Done...............................................................................34Disable Limits ................................................................................................................34

3 Advanced Functionality ..................................................................................... 35

Arranging Control Panels...................................................................................................35

Chromium Users Guide

Contents

4

Layouts ............................................................................................................................ 36Image Maps..............................................................................................................................37

Mosaic Maps .................................................................................................................. 37Importing an External Image ................................................................................. 37Manual Alignment....................................................................................................... 37Using Alignment Marks............................................................................................. 38

Exporting to Iolite and CellSpace ...................................................................................39Saving the files .............................................................................................................. 39Resulting files ................................................................................................................ 40

Notifications ............................................................................................................................40Troubleshooting and Diagnostics ..................................................................................41

Stages and motors....................................................................................................... 41System Log Viewer ...................................................................................................... 41

eQC...............................................................................................................................................42On-Demand eQC Measurement .............................................................................. 42eQC Run Scan Measurement.................................................................................... 43eQC Setup........................................................................................................................ 43eQC Laser Setup............................................................................................................ 44eQC Calibration ............................................................................................................ 44eQC Service Mode Settings ....................................................................................... 44

4 Analysis Quick Start.............................................................................................45

Building Sequences ..............................................................................................................45Triggering .................................................................................................................................45

1 Introduction

Overview This document is a Quick Start guide to show you, the user, the basics on how to use the Chromium software to operate your Teledyne Photon Machines or Teledyne CETAC Technologies laser ablation system.

Refer to the Operator’s Manual for your laser ablation system for instructions on how to set up the instrument and for important safety and regulatory information.

This document applies to Chromium version 2.2. There may be minor differences in the user interface for other versions of Chromium.

PrerequisitesThis document assumes that Chromium has been installed on the control computer and you are familiar with laser ablation applications and methods.


Chapter 1: Introduction

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2 The Basics: An Overview of Chromium

Control of the laser ablation system is accomplished through the Chromium software, accessible from the desktop of the control computer. On excimer based systems, the ATL 4 Valve software is used to maintain the laser head, and Chromium controls all other aspects of the laser ablation system.

Chromium Start-up1 Switch on the power to the laser system.

For excimer based systems, both the main switch, located to the rear of the system, and the key switch must be turned on. For LSX platform systems, the main switch on the rear of the unit must be switched on, along with the key switch located on the laser head power supply/chiller. Make sure that the red Emergency STOP button is not depressed.

2 Double click the Chromium icon located on the desktop.

Chromium starts with a checklist that confirms all devices were found before proceeding to the opening screen. An example from the LSX platform is shown in FIGURE 2-1.


Chapter 2: The Basics: An Overview of Chromium

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FIGURE 2-1 Device Manager Startup Screen

3 If any device is not found, check all cables and connections, then click the Find Devices button at the bottom of the checklist, which will make the software scan for devices again. If this is unsuccessful, a Full Search may need to be run: this tests each available COM port and checks if any device is connected to it and, if so, which device is connected.

4 Once all devices have been found, you can either wait for Chromium to advance to the main screen or click Continue.

The laser ablation system has several motors that are initialized and homed each time the software is run. This does not include the X-, Y- and Z- stages as Chromium remembers the last position they were in, provided the system has not been power cycled. It is recommended to home the stages in this case.

Homing MotorsYou can choose to home any motor manually if, at any time, you are concerned that a motor has lost its position. To home the XYZ stages, click on the location indicator on the bottom task bar. This will open the Move Stages dialog (FIGURE 2-2).



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FIGURE 2-2 Location indicator (bottom task-bar) and Move Stages dialog

From here, you can home the stages, move to a defined position, or simply jog the stages a set amount.

Other motor homing controls are accessed through their respective settings panels. These are accessed through various “gear” icons ( ) throughout Chromium and expanding the relevant Motor Controls section.

The attenuator and aperture (referred to as the “mask”) are both accessed through the Laser Control window, under Laser Energy and Spot Size respectively.

The zoom motor is accessed through the Field of View / Zoom Settings menu item, under the View Settings gear situated in the lower left corner of the main viewport.



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Navigating ChromiumChromium provides you with intuitive controls and great flexibility in how the dashboard is arranged. The main viewport is capable of importing multiple sample maps, such as SEM images, and aligning these to the laser stage coordinates. The camera is superimposed over the top of all these layers, allowing you to judge and navigate the position of the laser over the sample (FIGURE 2-3).

FIGURE 2-3 Main Window

Control PanelsDifferent function groups are located in Control Panels that can be docked to surround the main viewport. Some of these are shown in FIGURE 2-3.



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Main Viewport

FIGURE 2-4 Main Viewport of Chromium

The main viewport comprises a central area where the internal camera appears inside a “camera box” superimposed over the accessible area of the laser cell. Within this area, you can generate or import navigational image maps to assist you in finding and targeting features of interest in your sample.

Surrounding the central area are:

Video Focus, Zoom Controls and the Scan Toolbox on the left The Image Layer Management panel on the top Motor and mouse interaction mode controls along the bottom

Optical ZoomThe Optical Zoom controls adjust the zoom level of the video system. The large Zoom In and Zoom Out buttons step the zoom level in 25% increments, while the small arrows step the zoom in 5% increments.

5% increments

25% increments



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Video FocusThe Video Focus controls allow you to adjust the focus of the laser beam and video system onto the sample surface. The focus can either be stepped (single click on the focus button) or driven (focus button held).

FIGURE 2-5 Video Focus Controls

The focal plane of the video system and the laser beam delivery are confocal, that is they are at the same z-location.

Additionally, the depth of focus (and hence the focus error) is larger at low zoom. For the most accurate results, focus on the sample at 100% zoom.

TIP

The Z Focus + button increases the distance between the objective lens and the sample surface. When focusing on a transparent sample, if you are unsure of whether you are focused on the top or bottom plane of that sample, you can drive the stages down using the Z focus + button. If another plane comes into focus, then this is the top plane.

The mouse wheel button allows you to assign either control of the image zoom (digital zoom) or the focus ( Z-axis position)

Autofocus uses an image quality measurement to determine where the focal plane lies. From a particular focal plane, the algorithm steps through a series of z-values bracketed around the starting focus position to determine the focal plane with the best image quality.

The Coarse autofocus button uses a large range to find an approximate match, followed by a smaller range to hone in on the correct focus position. The Fine autofocus button only runs the smaller range.

To adjust the range and the number of steps for each autofocus mode, click on the gear icon. This brings up the Autofocus Setup dialog (FIGURE 2-6). Increasing the number of steps increases the accuracy of the autofocus.

You can also review the image quality data (“Q” values) calculated by the algorithm for the last autofocus determination.



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FIGURE 2-6 Autofocus Setup Dialog

Place/Move ScansThe Place/Move Scans toolbox has all the commands you need to navigate and lay out ablation patterns in a sequence for your experiment.

FIGURE 2-7 Place/Move Scans

Navigate Sample: this is the default mouse mode and it allows you to move the stages using the mouse. A single click will move the crosshairs to the selected position. Holding the mouse button down will move the crosshairs continuously towards the cursor position. The speed of movement is dependent on the distance of the cursor to the crosshairs: the further away the cursor, the faster the stage movement.

For all other tools in the toolbox, single-click navigation is accessible using the middle mouse button (clicking down on the scroll wheel).

Select/Drag: allows you to select and edit patterns already drawn onto the sample surface. You can move the endpoints, the whole scan or a group of



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scans (using the Shift key on the keyboard). You can also copy scans to new positions using the Alt key on the keyboard.

Measure: allows you to measure the distance between two features on the sample surface. The measurement appears in the bottom taskbar of the main viewport:

Note that these measurements are also shown when drawing patterns.

The rest of the tools are used to draw patterns:

Tool Name Short Description

Spot Single point ablation using a defined number of shots. Clicking <F5> will lay a spot at the current location of the crosshairs. This will also enable the use of StageVision for the current spot if enabled on the system.

Line of Spots

Series of single point ablations in a line using a defined number of shots.

Grid of Spots

Series of single point ablations in a grid using a defined number of shots.

Line Continuous ablation from one point to another in a straight line at a defined scan rate. Line scans can have multiple segments. Left-click to fix the starting point of the line. Subsequent left-clicks will anchor turning points when drawing a segmented line. When all desired segments have been mapped, right-click to terminate the line.

Raster Continuous ablation from one point to another in a raster grid at a defined scan rate.

Alignment Marks

Used to align image layers to the coordinate system of the laser (See ‘Using Alignment Marks’ on page 38).

Area Series of line scans to cover a freeform defined area.

Curve Continuous ablation from one point to another in a spline curve. The curve can be built up using several points.

eQC Allows for placement of an eQC spot. This can be used to monitor energy delivery to the sample surface at routine intervals.

View SettingsIn the bottom-left corner, the View Settings gear allows you to access a number of features related to the video screen.

FIGURE 2-8 View Settings



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Autopan moves the stages with any tool that requires at least 2 mouse clicks to be set correctly, for example the Line tool. The first click will set the first vertex, and when you move to the edge of the screen in the main viewport the stages will track across allowing you to access areas of the sample which are outside the current field of view of the camera.

Field of View/Zoom Settings allows you to calibrate the field of view settings for each zoom level. This calibrates the Measure tool and the stage position of drawn patterns.

NOTICEThe Field of View/Zoom Settings should only be changed by qualified service personnel or if prior training on the proper procedure has been given. Incorrect settings will cause the laser to track incorrectly across your sample.

Graphic Overlay Properties allows you to adjust: Color of the crosshairs and drawn scans, and different colors when the

drawn scans are highlighted, active or inactive. Whether labels appear, whether they are shown as the text description or

the scan number, their size and where they are placed with respect to the patterns

FIGURE 2-9 Overlay Properties

Live Video turns the camera on or off in the main viewport.

Video Capture Settings allows you to adjust the physical camera settings (such as gain, gamma correction, color balance etc.) to fine tune your visual experience of the video system within Chromium.

NOTICE Adjust the video capture settings gradually and carefully. Inappropriate settings can result in a blank video image.



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Troubleshooting Live Video and Tracking

If the Video Display Is Blank1 Open the View Settings and click Live Video several times to toggle it between

on and off.

FIGURE 2-10 Live Video Off

FIGURE 2-11 Live Video On

2 If turning Live Video on changes the display from gray to black, this means that the lighting is turned off or the illumination is inadequate.

3 A solid black or white image can also mean that the video display or camera settings are not appropriate for the sample and illumination conditions. Recall a quickset or click Reset to defaults and gradually adjust the settings.

If the Video Image Does Not Move As Expected1 Check the Tracking button below the viewport.

With tracking on, the live video window and crosshairs will remain centered in the viewport while the sample is moved via the stage controls.

With tracking off, the video can be moved around within the travel limits of the stages. The stages will not be moved and the controls simply adjust the location of the video image on the display.



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FIGURE 2-12 Tracking Off

FIGURE 2-13 Tracking On

2 Check that the stages are not at their extreme limit of travel. When a stage reaches its limit, the video window and cross hairs will displace toward that direction until the stage travel limit is hit.

Layers and Images

FIGURE 2-14 Layers and Images Toolbar

Layers and Images shows all the currently loaded images (and the live video). Each image is on its own “layer” where the order of the images/layers in the list corresponds to the order in which they appear on the screen—the layer at the top is displayed on top of the other layers. You can use the mouse to drag a row in the grid to rearrange the order in which they are drawn on the screen.



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The following columns are shown:

Show – use this column to toggle the display of an image or layer.

Locked – when checked, an image is “locked” and can't be moved or sized with the mouse. If you clear the check mark in this column, then the corresponding image will have a “rubber band” box drawn around it in the main display, and you can use the mouse to drag and re-size the image to align it with the sample. Note that the Live Video layer is always locked.

Opacity – click in this column to change the transparency of the image or layer.

Layer – description or file name of the image.

Actions – click on an item in this column to:

o Goto – moves the stages to position the laser at the center of the corresponding image.

o Align – brings up the Alignment dialog. (see Image Alignment for more information).

o Remove – removes the image from the list, but does not delete the image from disk (if the image is a mosaic or image which you have captured, then the software will ask if you want to delete the file from disk).

The toolbar above the has the following functions:

Recall Map – recalls a previously saved map. A “map” file contains a list of all the images/layers and their settings and alignments.

Whenever you close the software it automatically saves the current image map in file called “_DefaultImageMap”.

Grab Image – captures an image from the live video camera and adds it to the image list.

Build Mosaic – use this to capture and stitch together a set of images over a large area of the sample. When you click on this button, a “rubber band box” is displayed in the video/image display area; use the mouse to size and position this area to the desired size and location, then click on the Capture Images button and the stages will move around the area and images will be captured. Be sure to focus on the sample first, or all the images will be out of focus. If the sample is in focus but the images still appear blurry, try increasing the “Settling Time” option to allow the stages to settle into position longer before an image is captured.

Mosaic images are automatically put in a folder named “My Pictures/Chromium2/Mosaics”, and the images are saved with a name that corresponds to the current date and time.

Save Map – click to save the current image map (layer and image list) to a file.



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Import Image – click to import and align an image. Supported image types include: Bitmap, JPEG, PNG and TIFF. See Image Alignment for more information.

Erase – clears out the image map, removing all images from the list, but does NOT delete any files from disk.

Export Map Files – Saves the current image map, image files, and scans into the selected folder. This makes it easier to copy images and scans to another system without having to manually find and copy each image, map and scan file.

Saving a Video ImageTo simply save an image of the main camera video, without overlays and without adding it to the image list, select File > Save Video Image. This will bring up a standard save file dialog box.

Laser Control

FIGURE 2-15 Laser Control Panel

The laser control panel allows you to manually fire the laser, control the laser output energy, the size of the spot on the sample surface. It also allows you to read back the current energy produced by the laser head, as well as the calculated fluence at the sample site.

FIRE LaserFIRE Laser fires the laser will fire if the FIRE Laser is clicked when the icon is RED in color. When gray, as seen here, the laser will not fire.

Before firing the laser manually, the laser first needs to be enabled.

On Analyte platform systems this will cause the laser head to prepare for firing. Thyratron based laser heads have an initial warm up time of around 5 minutes after fire starting the system. All subsequent enabling of the laser in the



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software takes 5 seconds. For Solid State based laser heads will also enable in 5 seconds.

On the LSX platform systems, this will cause the pump activate and begin circulating coolant. The flashlamp can be fired independently from the Q-switch. This can be used to get the system to operating temperature prior to firing the laser, this can increase shot-to-shot stability at the expense of flashlamp lifetime.

The shutter can be either left open or closed depending on preference. The laser will then ablate the sample centered over the crosshair.

Fire ModeFire Mode allows you to run the laser in one of three modes:

Continuous: the laser will fire continually with the current settings until shut down.Burst: the laser will fire for a set number of shots entered directly below.Single Shot: the laser will fire just one shot.

Laser EnergyLaser Energy allows you to select a percentage of the total available laser energy. The fluence is reported for the sample site and is calculated based upon the total energy currently being produced by the laser head, known losses through the system and the current spotsize being used. A required fluence can also be entered into the fluence section. This will automatically move the attenuator to deliver the fluence entered.

Spot SizeSpot Size allows you to change the currently selected spot.

1 Click the + to the left of Spot Size.

FIGURE 2-16 Spot Size in the Laser Control Panel

2 Click the down arrow to the right to select the size.

FIGURE 2-17 Spot Size After Clicking +



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FIGURE 2-18 Spot Size Selection

The Settings gear icon opens a menu lets you change the motor settings for each spot size. Changing these settings is not recommended unless you wish to change the preset spot sizes. Call Teledyne Photon Machines if you need to make changes.

Laser StatusLaser Status provides information relating to the laser head.

Interlock information is provided here, where interlocks showing as green are operating normally, those that are yellow are informational, and those that are showing red are interlocks that are currently broken. Interlocks showing either yellow or red will prevent the system from firing.

For excimer systems a stale gas warning will appear in yellow, this does not prevent the laser from running, and is shown when the excimer gas life time has nearly expired. This is determined based on the voltage currently being applied in the laser head to achieve the setpoint energy level.

The ATL excimer laser on the Analyte platform can deliver an Internal Interlock notification. For more information on this interlock, please open the ATL 4-Valve Software.

The Quantel Ultra laser head on the LSX platform systems reports back a large number of interlocks, however, key interlocks are those from the coolant flow, which will show as Low flow in yellow until the laser is enabled and the pump begins to run or if there is a fault with the pump, and the Sample Chamber interlock which will show as a red BNC interlock until the sample chamber door is fitted correctly.

For Analyte platform systems the Excimer Laser Status gives a readback of the current energy output, reported in milliJoules (mJ). The laser head can be set to one of three operating modes to control the output energy.

• Voltage stabilized mode – The laser head will adjust to the voltage entered. The energy delivered will slowly decline as the gas lifetime is used up. This mode can be used to determine the health of the laser head. Setting maximum voltage, 17 kV or 1.3 kV for Thyratron and Solid State systems, respectively, will show the maximum achievable energy level. For a new laser head this is typically > 12 mJ. This maximum energy delivered depends upon the condition of the



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internal optical system, the gas quality the temperature and pressure of the laser head.

• Energy stabilized mode – The laser head will adjust the voltage automatically to achieve the required energy output, can be set using the setpoint setting to anywhere between 3 and 9 mJ. The voltage will increase over time as the gas life is used up.

• Energy w/PGE Mode – This Energy with Partial Gas Exchange mode will automatically adjust the voltage to achieve the setpoint energy. However, once the voltage gets too high, the system will automatically remove and replace some ArF gas to ensure that the energy setpoint is always achieved. This continual cycling of gas will increase the cost of analyses.

View Controls

FIGURE 2-19 View Controls Panel

In this control panel, you can control the lights and some basic camera controls. The Lights section sliders control the amount of light output by the three different light sources in the system. The Video Display sliders control the brightness and contrast of the image displayed in the camera box in the main view port.

The Camera section is where you can control the exposure of the image inside the camera box by varying the time the camera aperture stays open for each video frame as a percentage of maximum time. The Auto-Exposure check box automatically adjusts this time to a reference level that you can set using the View Settings gear (see page 11).

The Quickset buttons allow you to quickly access lighting conditions that work well for samples which are particularly tricky to view. To set a Quickset, hold down the desired number until the “Quickset” text flashes with a red background:

FIGURE 2-20 Lighting Quickset Buttons



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Gas Controls

FIGURE 2-21 Gas Controls Panel

The Gas Controls panel allows you to control the state of the internal valves along with the MFCs. There are five possible states under Sample Chamber Valves for the internal valve system:

Bypass – The default when starting the software. In this mode the cell is bypassed, this allows for samples to be changed without affecting the ICP system. The system automatically switches to bypass mode when the sample chamber drawer is opened while the ICP torch is lit.

Online – The gas flows are routed through the cell. Ablated material is carried to the ICP in this mode.

Purge – The gas flows are routed through the cell, however, gas is carried out through the purge port. The ICP carrier / nebulizer gas is still routed through to the ICP to stabilize the plasma. You should switch to purge mode before routing any carrier gas through the sample chamber to the ICP-MS, to clear any air that may have entered the gas lines while the sample chamber drawer was open. You can set a Purge Timeout, after which the purge mode will automatically switch to online mode.

Evacuate – The internal vacuum pump is utilized to evacuate the cell using slightly negative pressure. The cell is then backfilled using Helium, purging though the purge port on the rear of the system. This is cycled several times to improve evacuation efficiency. The Status submenu shows the current status of the evacuation pump along with real-time pressure read back from the MFC’s.

Argon Only – (LSX Platform only) – Argon from the ICP nebulizer supply is routed through to the cell input. This allows for purging the Cell with Argon if required. It can also be used to run the Cell in



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Passive mode, allowing the use of Argon as a carrier gas. Sensitivity will likely be reduced in this mode

eQC – (Optional Extra – appears when fitted only) This is the gas mode used when the eQC function is being used

Under Mass Flow Controllers you can control and see the current flow set points. You can also stop all flows and run the auto flow control routines from this point.

The number of MFCs shown will depend on your current system configuration. All systems are capable of running up to 3 MFCs. Additional MFCs can be fitted at any time; up to a system total of three.

The Gas Flow Setup… submenu allows you to customize the auto flow control routines, allowing for changes to ramp time, flow rates for each MFC, the number of evacuation cycles and the selection of which mode should follow the evacuation.

Controlling the Beam Purge Gas

There are two kinds of purge: beam purge and carrier gas purge. This section describes beam purge; page 25 for carrier gas purge.

When the laser is firing the beam train should be purged with nitrogen to displace the atmospheric air. Doing so extends mirror life and improves beam transmission. To turn on the beam purge gas, check the Beam Purge Valve check box. If you attempt to start firing the laser without turning on the nitrogen, Chromium will ask you if you wish to turn on the gas.

To avoid unnecessary gas use, the purge gas valve is automatically shut off after 5 minutes by default. This timing can be adjusted if desired by typing a different number into the Idle Timeout field of the laser control sub-window.

Note that, if desired, noble gases such as He or Ar may be used as a beam purge. For more information on the beam purge see the Operator’s Manual for your laser ablation system.

Mass Flow Controllers and Gas ControlsMass Flow Controllers (MFC) regulate the flow of carrier gas and make up gas through the system via software control. Control of the MFCs can either be manual or automatic.

Manual Flow Control

If the Auto Flow Control check box in the Mass Flow Controllers section is cleared (see FIGURE 2-26), the user has manual control of the flow rates. Click within the Setpoint box for the appropriate MFC to enter the flow rate for that gas in liters per minute (LPM). Once the number is entered the MFC will ramp up or down to the setpoint. The actual “real-time” flow rate is indicated in the box above the flow rate setpoint.

With manual control the MFC maintains the set flow rate independent of any switching of gas flow mode. See the see the Operator’s Manual for your laser ablation system for flow rates; a typical maximum flow rate for each MFC is 2



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LPM. It is recommended to keep each MFC to a maximum of 1 LPM and to adjust the flow rate in increments of 0.1 to 0.3 so as not to disturb the ICP-MS torch.

Automatic Flow Control

If the Auto Flow Control check box in the Mass Flow Controllers subsection is selected, then gas flow rates will automatically be changed as the gas flow mode is changed (between online, bypass, and purge). You can set the desired flow rates for each of the three different gas flow modes (online, bypass, and purge). Additionally, you can set how long the MFC should take to ramp up to the set value. These settings are accessed by clicking on the gear icon next to Setup Gas Controls. A dialog box appears where flow rates and ramp times can be set, as desired, for each flow mode in the Automatic Flow Control Settings section.

The Valve Solenoids Configuration settings, if present in this dialog box, should not be changed as it could lead to incorrect valve switching of the gas flow.

Purging

There are two ways to purge the sample chamber carrier gas: 1) purge with helium only at a high pressure for approximately 10 minutes without the built-in vacuum pump or 2) alternate between vacuum pump and purge for six cycles. The latter ensures that air is pulled out of trapped areas. The default settings in the Gas Control window provide for the vacuum/purge method.

FIGURE 2-22 Gas control configuration window.



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NOTICENever adjust the values for Max. Pressure, Evacuate Backfill and Evacuate Pressure or the sample cell window may break.

The system will automatically switch to online mode after the time set for purge timeout elapses or when the evacuate cycle has ended, at which point the sample will then flow to the ICP-MS.

Gas Flow Strategies Once the optimal ONLINE flow rates have been determined for a particular

ICP-MS for MFC1 and MFC2, enter these values into the ONLINE fields in Gas Flow Configuration window shown in FIGURE 2-15. Setting a ramp time of between 30 and 60 seconds will provide for a gradual increase in flow when the solenoids automatically switch from PURGE or EVACUATE to ONLINE so as not to extinguish the torch.

When in BYPASS mode it is best to have some residual helium flowing to keep the tubing clear. Settings of 0.1 LPM to each MFC is typical and a ramp time of 10 seconds.

If using PURGE mode to clear the sample chamber of air after loading samples, then the 600 second purge timeout default setting should be an adequate duration with flow rates of 1.3 LPM to MFC1 and 0.2 to MFC2 and a ramp time of 30 seconds so as not to stress the window. Note that during the Purge cycle, no helium is going to the torch.

PURGE END adjusts the gas flow to a low level before switching ONLINE to prevent the torch from being extinguished when the helium is again introduced. Typical settings are 0.1 LPM for both MFC1 and MFC2 and a 5 second ramp time.

When using the EVACUATE cycle for clearing the sample chamber of air, no helium is going to the torch. The cell will be evacuated then back filled a preset number of times. The window will “flex” and the image on the screen will appear to move during evacuation. At the end of evacuation (EVACUATE END) the settings should be similar to those of PURGE END, typically 0.1 LPM each for MFC1 and MFC2 and a ramp time of 5 seconds.

In addition to the two mass flow controller dedicated to the HelEx sample chamber, a third MFC can be added to “spike” the helium carrier gas with N2 or other gases for the purpose of enhancing the ICP-MS signal when analyzing certain types of materials. See the publication:

Guillong, Marcel; Heinrich, Christoph A. Sensitivity enhancement in laser ablation ICP-MS using small amounts of hydrogen in the carrier gas. J. Anal. At. Spectrom. 2007, 22, 1488–1494.



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Scan List

FIGURE 2-23 Scan List

The Scan List is where data relating to any patterns laid down in the video appears. The number of patterns that can be placed in the list is practically limitless. The list section of the Scan List is split into several columns:

No. – Each pattern in the list is given an Index number. These are sequentially and automatically assigned as you lay down patterns.

– This column shows whether the pattern is currently enabled. A tick here shows that the system will processes this line during an ablation run. Clicking <Space Bar> will enable or disable any highlighted scan.

– Gives a visual representation of the current status of the scan, Pending, In Progress and Completed.

– Shows whether the current scan is enabled for a Preablation Pass.

– Shows whether the current pattern is enabled for an Ablation Pass.

Type – Gives a visual representation of the pattern type.

Description – User editable description of the pattern. The system will automatically generate a description based on the pattern type along with a sequentially assigned number.

Position – Shows the origin X, Y and Z position of the particular pattern. Within this section, Go To will go to these coordinates and ‘Edit’ will open a screen allowing the user to edit both the origin position and the end position (if applicable to the pattern type) of the pattern.

Laser Output (mJ) – The laser output requested from the laser head.

Fluence (J cm-2) – The calculated fluence requested at the sample site.

Rep Rate (Hz) – The requested laser repetition rate requested from the laser head.

Shot Count – Spot type patterns only – The amount of shots to lay down on a particular spot.

Scan Speed (µm s-1) – The speed at which the laser will traverse a line type pattern.

Spot and Line Spacing (µm) – The spacing between spot and line centers, used for line and grid of spots and area type patterns. As such for a 20 µm diameter spot to be spaced edge to edge, a value of 20 µm must be entered here.



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Iteration Count – The number of times the pattern should be repeated.

Spot Size – The size of the spot selected, this also selects the width any line type patterns.

– normally hidden unless a scan is highlighted – this allows viewing of any data saved relating to the highlighted scan. This includes, for example; the start time and end time of the scan, an image pre- and post-ablation if requested, etc.

When a scan is placed it will use the default values shown at the top of the scan list. These default values can be edited at any time. The default values can be copied to any highlighted scans using Copy Settings..; this will also allow you copy any settings from the manual laser controls. If, for example, you wanted to change the energy of highlighted scans whilst leaving the remaining parameters as is, then you can use the Apply Settings button. This allows you to select which parameters you would like to update, whilst leaving any which are unchecked as is.

Scans in the list can also be saved and recalled at a later time. These can be saved either as a Chromium Experiment file (*.lase) or exported for use in Iolite as a (*.iolite.csv) file. When saving as an experiment file, all data relating to the current Chromium configuration is saved, along with any and all data associated with the scan list. These functions are accessed by the Recall and Save buttons.

The Scan Review button will open the Scan Review Dialog:

FIGURE 2-24 Scan Review Dialog

The scan review dialog allows final adjustment of the X, Y and Focus position of all Enabled scans, prior to running those scans. The scan position adjustments can be performed automatically, or manually. Whether in Automatic or Manual mode, the scan points that can be adjusted are the same points that defined the scan. So for Grids and Rasters, the upper left and lower right corners can be adjusted. For Lines, Lines of Spots, Curves and Areas, each Vertex or endpoint of the scan can be adjusted.



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Auto Focus Adjust – The Automatic mode will only adjust the focus position (not the X or Y). Clicking the Start button will automatically step through each enabled scan, and auto focus the scan.

Manual XY and Focus Adjust - The manual method allows manual or automatic adjustment of the focus position, and also allows manual adjustment of the XY position.

The manual mode controls are:

Auto Focus after moving to endpoint –If this box is checked, then auto focus will automatically be performed when moving to the next vertex or scan.

Vertex – Move to the next vertex in the current scan. If the current vertex is the last vertex of the scan, then move to the next scan.

Prev – Move to the first vertex of the previous scan.

Next – Move to the first vertex of the next scan, skipping over remaining vertices of the current scan. Note that as the buttons are clicked, the stages are positioned to the vertex to be adjusted, and that vertex is centered at the crosshair in the video window. The mouse can be used to click and drag the vertex to fine tune the XY position as desired (as long as auto focus is not currently in progress).

List Editing Toolbar At the bottom of the Scan List window is a toolbar that is helpful in organizing the list of scans. Scans are run in same order as they are listed, so changing the order in the list changes the order in which they will be run.

The buttons perform as follows:

All – Highlight all scans in the list. If all scans are already highlighted, clicking it again will unhighlight them all.

Delete – Delete all highlighted scans in the list. A window will pop-up requiring confirmation before actually deleting the scans. The keyboard Delete key can also be used to delete highlighted scans.

To Top – Move all highlighted scans to the top of the list (i.e., run these scans first).

To Row – Move all highlighted scans to a specified row. This will pop up a window requesting a row number, and then insert the highlighted scans immediately preceding that row.

To Bottom – Move all highlighted scans to the bottom of the list (i.e. run these scans last). ,

Rename – Allows for renaming of a group of selected scans in the scan list.



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FIGURE 2-25 Rename Scans Window

The Rename Scans window will open, allowing entry of a base name and a starting sequence number. Enter a base name like NIST612-, and a starting number of 1, and click Apply. The selected scans will then be renamed as NIST612-1 through NIST612-12.

Scans can also be moved within the list by dragging them. Use the mouse to highlight multiple scans, then click and hold the left mouse button on an already highlighted scan, and drag to the new desired location. All highlighted scans will then be moved to that location (if they were not consecutive before the move, they will be consecutive after the move).

Scans are run from the Scan List toolbar by clicking This will open the run scans dialog:

Run Scans Dialog

FIGURE 2-26 Run Scans Dialog



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The Run Scans dialog allows you to run any scans that are enabled for ablation in the scan list. It allows you to control how the preablations and ablations are run, along with controlling triggering of the ICP-MS, adding delays to control timing of runs, and setting up the current gas mode.

During a run the Run Scans dialog will remain on top of the screen, once running you can no longer move the dialog. You can, however, minimize the dialog to the lower right of the screen.

There are several sections to the Run Scans dialog:

Pass Sequencing – gives several options to control how preablations are handled, an option to disable any scans that have been completed and also to log the XYZ positions during the run.

o Preablation Sequence - Three modes are available:

Preablate all, then ablate all mode, the preablation pass is performed on ALL selected scans BEFORE any ablation passes are performed. Once all the selected scans have been preablated, the ablation pass is next performed on each scan.

Preablate EACH scan, then ablate EACH scan mode, the software will perform the preablation, then the ablation pass on EACH scan before proceeding to the next one.

Preablate EACH spot, then ablate EACH spot mode, will result in each spot within the “line of spots” and “grid of spots” scan types to be first preablated then ablated before moving on to the next scan.

In the scan list window, the preablation and ablation passes can be enabled or disabled for any individual scan. If any scan has the preablation or ablation pass disabled, then that pass for that particular scan is skipped.

o Log XYZ Positions, when checked, the XYZ position data and timestamp is stored once every two seconds for Line, Raster, and Area scans, while the scans are running. After running the scans, this data can be saved by clicking the Save Experiment button, and selecting “Line Scan Data” in the Save as Type box. The resulting file is a text file containing scan parameters for each scan, and a table of the timestamp and position data for each scan.

Mass Spec Trigger Setup – depending on the ICP-MS hardware the system can accept a trigger input from the ICP-MS and also output a trigger to the ICP-MS. selects whether the signals are active-high or active-low.

There are hardware jumpers inside the system which select whether a trigger signal is using a TTL (logic level) voltage, or a contact-closure (relay) interface.



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Scan Run – This section provides information on the currently enabled scans. It shows you how many scans are enabled for a run, the estimated run time of those scans, the elapsed time of the current run, how many scans have been completed, which scan is currently running and the current status of the Instrument.

o An option is provided to Fire the laser during scans. Unticking this option will result in the system proceeding through the scans but without the laser running. This is useful when first setting up the triggering for the ICP-MS, or when checking timings of the run.

o For LSX platform systems, you can select whether to run the flashlamp for a short time before the run, and its corresponding delay and whether to turn off the flashlamp between scans. Running the flashlamp before firing the laser can increase initial stability at the expense of flashlamp lifetime.

The Show Trigger, Delays and Gas Mode Panel button will expand the Run Scans dialog and show additional options.

FIGURE 2-27 Triggers, Delays and Gas Modes Panel

There are two tabs (Preablation and Ablation) – each tab has the same settings available, but the values for each tab can be set differently so that the preablation and ablation action settings can be set independently.



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Actions at Start of Preablation/Ablation Pass At the top are the actions that can be set to happen at the beginning of a pass (either the Preablation or Ablation pass):

Wait for Trigger In – select this option to have the software pause until the hardware trigger input is received.

Set Gas Mode – select this option and then pick the desired mode, and the software will then automatically switch to that mode at the start of the pass.

Activate Trigger Out – select this option and the software will activate the trigger out signal. In addition, on some systems you can select a Delayed Activation which means the software will go ahead and continue to execute the scan, but the actual hardware trigger signal will get delayed by the specified amount.

Pause – specifies a number of seconds for the software to pause. This is useful if you need to allow time for gas flows to stabilize, etc.

If the Preablation Sequence setting is “Preablate ALL Scans First”, then the “Start of Preablation/Ablation Actions” only happen once, at the beginning of each pass, when the first scan is about to be preablated or ablated. If the Preablation Sequence is set to “Preablate, then ablate EACH scan”, then these actions will be performed on each and every selected scan pattern in the scan list as each one is preablated and ablated in turn.

Actions for Each Pattern The next set of actions define what happens right before and right after each scan pattern (line, spot, raster etc..) is ablated or preablated. Normally, “line of spots” and “grid of spots” patterns are treated as a single scan and so the start and end actions are only performed once on each of those patterns, but if the Do Actions on Each Individual Spot of a Line/Grid of Spots option is selected, then the Start and End actions are performed on each and every spot of the line or grid of spots, so the in effect the software will treat each spot as if it is a separate scan.

Actions at Start of Each PatternOnce the preablation or ablation actions have been performed (if any are selected), the software next prepares to actually execute a scan (i.e., use the laser to preablate or ablate a spot, line raster pattern etc.). Before the laser is activated and the scan is performed, you can select which actions to perform. The same actions which are available for the “Start of Preablation /Ablation Pass” are available, and they function the same. The main difference is that these actions (if any are selected) will be performed on each scan pattern (spot, line, raster etc.) just before the laser is activated.

If a scan pattern has its Iteration Count parameter set greater than 1, then a Pause between Iterations will be inserted at the end of each iteration (except for the last one) to allow for a delay between iterations if desired.

The Z Step Size per Iteration feature allows stepping the Z axis between iterations while ablating a scan. The intent is to keep the laser focused on the



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bottom of the crater on each iteration. A test run should be performed in order to determine what depth of material is removed in a single pass.

Actions at End of Each Pattern Once the lasing is done on a given scan, then another set of actions can be set to happen, before the next scan is processed:

Clear Trigger Out – deactivate the trigger out signal.

Set Gas Mode – select this option and then pick the desired mode, and the software will then automatically switch to that mode.

Pause – specifies a number of seconds for the software to pause.

Actions at End of Preablation/Ablation Pass The same set of actions which are available for the “End of Each Pattern” can be setup to occur at the end of each preablation or ablation pass.

If the Preablation Sequence setting is “Preablate ALL Scans First”, then the “End of Preablation/Ablation Actions” only happen once, at the end of each pass, after the last scan has been preablated or ablated. If the Preablation Sequence is set to “Preablate, then ablate EACH scan”, then these actions will performed on each and every selected scan pattern in the scan list after each one is preablated and then ablated in turn.

Shut Off Gas Flows When Done If this option is selected, then when a scan run is completely finished, the gas flows on all the mass flow controllers will be set to 0. This is useful to save gas when doing long, unattended runs.

Disable LimitsIn some circumstances, it is possible for electrical noise from other lab equipment to cause a stage limit switch to appear to be momentarily tripped, which will cause any motion on the affected axis to stop temporarily. The signal is too short in duration to be detected by the software, so no errors or indicators are displayed to let the user know that the scan is no longer following the correct trajectory. When this box is checked, the stage limit switches on the X and Y axes are disabled while running scans – this will prevent any noise transients from affecting the motion of the stages during the scan.

NOTICE

Only use the Disable Limits option if you suspect that electrical noise is affecting the stage limits, and make sure that your stages and scans have been positioned properly, since when the limits are disabled there is nothing to prevent the stage motors from running in the hard-stops on the stages and possibly damaging the motors.

3 Advanced Functionality

Arranging Control PanelsTo arrange the control panels, first ensure the layout is unlocked by clicking on the padlock icon ( ) in the upper left corner of the main window. When the icon shows the unlocked padlock ( ), the control panels can be moved.

The control panels themselves can be positioned such that they are either:

Floating to be placed anywhere in the main viewport, or even anywhere on your desktop, which is useful if you are running a second monitor.

Docked along the sides of the viewport, such as Laser Controls shown in FIGURE 2-3 on page 10.

Docked as a tab with another control panel, such as View Controls and Gas Controls, also shown in FIGURE 2-3 .

The control panel can be toggled on and off through the view menu:

FIGURE 3-1 Control Panels Menu

Once toggled, grabbing the taskbar of the control panel will allow you to move and dock the screen to whichever position best suits your workflow. As you hold the mouse button and move the control panel around the viewport, a blue preview box appears that will show you the final position of the control panel once the mouse button is released.


Chapter 3: Advanced Functionality

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LayoutsChromium allows you to save and recall different layouts of the control panels. Both options are accessible through the View > Layout menu. These layouts will appear as different tabs in the main software, allowing you to keep customized dashboards suited to specific workflows separate yet accessible at all times.

FIGURE 3-2 Layout Menu



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Image MapsFor macro navigation, Chromium has two options for image maps:

Mosaic Map Generation, using the main camera and viewport Importing external images and aligning them to the viewport.

Mosaic maps are great for high-resolution images of your sample, but may be time consuming to acquire. External images have the advantage of being quick and easy to setup, but may not have the desired resolution for the work required.

Mosaic MapsTo generate a sample mosaic, in the Layers/Images section of the main viewport click the Build Mosaic.. button. This will generate a selection area that you can alter to suit the sample area you wish to be mapped.

TIP

To get the best looking mosaic maps, we recommend turning off the camera’s Auto Exposure feature in the View Controls Panel and manually tuning the exposure until you’re satisfied with the results.

Importing an External ImageTo import an image, in the Layers/Images section of the main viewport click the Import Image.. button (FIGURE 3-3). A dialog box will open allowing you to navigate your image. The image will import at the position of the crosshairs.

FIGURE 3-3 Layers/Images Manager Above the Main Viewport, With the Import Image Button Highlighted

Manual AlignmentThe Image Size and Alignment dialog will appear as soon as the image is imported (FIGURE 3-4). On the Alignment and Positioning tab, you can adjust the size and center position of the image map to align it to the camera viewport.



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FIGURE 3-4 Image Size and Alignment Dialog

When adjusting one dimension of the image size with the aspect ratio locked, make sure to click the other dimension to allow Chromium to calculate the required size before clicking Apply or OK. Clicking either button overrides the aspect ratio lock.

Using Alignment MarksAn easy way to align and scale your imported image to the camera viewport is to use the Alignment Marks tool. Using two reference points, Chromium is able to account for rotation, translation and scale of the imported image relative to the actual stage position.

To use the alignment mark tool:

1 Select the alignment mark tool from the left side of the main viewport (see page 11).

2 Choose a reference point on the imported image and track the stages to find the real position in the camera viewport.

TIP

When using a tool other than the Navigate Sample tool, use the middle mouse button to track the stages to the cursor.

3 Select the feature in the image first, then select the same feature in the camera viewport. Choose two features to enable alignment.

TIP

For the best accuracy aligning the images, choose two reference points that are situated far away from each other.

4 Select Align in the Actions column listed next to the image name in Layers and Images manager, then select the Alignment Marks tab.



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FIGURE 3-5 Alignment Marks Control Panel

5 Review each position and fine-tune endpoints if needed.

6 Once you are satisfied with the positioning of the endpoints, click Apply. The image will now scale, rotate and translate to ensure accurate mapping to sample positions.

Exporting to Iolite and CellSpaceThe Iolite software package is able to correlate sample position data from a laser ablation platform with the mass spectrometer count data, assuming both platforms produce the appropriately formatted data files. Additionally, the CellSpace component of Iolite is able to visually overlay the mass spectrometer count data on an image of the sample saved by the laser ablation software. The following describes how to save the appropriate data files from the Chromium laser ablation software, not how to use Iolite or CellSpace.

For information on using Iolite and CellSpace, an excellent tutorial can be found on the Iolite web page: http://ioliteblog.blogspot.com/2012/04/cellspace-images-tutorial.html

Saving the files The data required by Iolite and CellSpace includes the timestamps and stage positions when the laser is turned on and off. Therefore, the scans must be Run in the Chromium software, in order to generate the data. Once scans have been run, the Iolite compatible files can be stored by clicking the Export Data button under Save.

In the Export Data pop-up window, the Save as type selection must be changed to Iolite Data File.

After the Scan data (called the laser log file by Iolite) has been saved, another pop-up window will appear, allowing selection of images that can be saved for use by CellSpace. These be images from an SEM or other external source, that

http://ioliteblog.blogspot.com/2012/04/cellspace-images-tutorial.html



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were imported into Chromium, but could also be Mosaic maps or images captured directly from the system camera.

Resulting files The Scan data, or laser log file, will be saved as named, with a .csv extension. This is the format necessary for import into Iolite. Each selected image will be saved as a PNG image file, along with a coord file. The coord file identifies the image location within the sample chamber space, and allows CellSpace to relate the position data in the Scan data file to the image.

Both the image and coord files are required for import into CellSpace. All image and coord files are prefixed by the scan data name, indicating they relate to the scan data file.

Igor, the “host” program for Iolite, has a limit of 31 characters for a wave name. Iolite creates a wave based on the name used for the image coord file (and appends “_wave” to the filename). When saving images, if the name will be too long for Igor, Chromium will truncate the name. As such, the image name may be changed to “ImgXX” where “XX” is a 2 digit number representing the index in the list of image (such as MyTest_Img01.coord).

Notifications

FIGURE 3-6 Notifications Dialog

Chromium has the ability to send an email or text message to indicate successful completion of a scan run, or warn of an error during a scan run. The Notifications can be configured by clicking the Settings menu, and then



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Notifications. The Notifications window allows entry of multiple email addresses or phone numbers (US only) for notification.

Add – Enter an email address or phone number in the entry box, then click the Add button to add to the notification recipient list.

Test – Send a test notification to all email addresses and phone numbers in the notification recipient list.

Remove – Remove the highlighted entry from the notification recipient list.

A notification will be sent when any of the following events occur, and the corresponding check box is checked. The notification message includes the time stamp of when the event occurred.

Scan Start – a scan run was started.

Scan Done –a scan run was completed successfully.

Scan Abort/Error –a scan run was aborted by a user, or an error occurred.

Information Interlock – a low priority interlock was tripped.

Warning Interlock –a medium priority interlock was tripped (f6r example, someone opened the sample drawer).

Error Interlock – a high priority interlock was tripped (for example, a problem with the laser).

Disable All – Checking this box will disable the sending of all notifications until the box is unchecked. (For example, disable during the day, while staff members are present, but enable for unattended evening or overnight runs.)

Troubleshooting and Diagnostics

Stages and motors The troubleshooter will run a series of tests that check limits, offsets, and positions, to try to determine the source of a problem and then fix it.

The troubleshooter can be accessed from the Home Stages window, and will prompt for which axis it should check (X, Y or Z). The troubleshooter can also be used to help identify problems with the laser spot size and the attenuator motors. It can be accessed from the settings window of the respective motor.

System Log ViewerThe system log viewer displays informational and diagnostic messages which are normally not shown. Under normal operating conditions there is no need to view this data, but when troubleshooting issues it can be useful. The log viewer is enabled from the main menu by selecting View→Show System Log. In the system log window, the display of different types of events can be enabled/disabled by checking their corresponding checkboxes in the window toolbar.



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eQCThe eQC energy monitor provides a means of measuring the laser energy at the sample to verify energy stability over time. It can be run from the Laser Control panel to see the current energy level. Energy measurements can also be scheduled during scan runs via the eQC scan tool.

On-Demand eQC Measurement To measure the laser energy when scans are not in progress:

1 In the Laser Control panel, click anywhere on the line titled eQC. This will enable the Run button.

FIGURE 3-7 eQC in the Laser Control Panel

2 Click Run to start the energy measurement.

FIGURE 3-8 eQC Progress

The stages will move such that the eQC energy meter is in line with the laser (Positioning mode). The laser will then be enabled and run in Warming up mode (with the system shutter closed). Once the warm-up cycle is complete, the shutter will open, and Chromium will read the energy meter and collect measurements. The laser runs at 10Hz in eQC mode, and every laser pulse is read. After the process is finished, the measured fluence value (energy density) will be displayed on the eQC line.



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There is always some energy transmission loss through optics in any system, and the amount of loss may change over time. If the software calculated Fluence (shown in the Laser Energy section of the Laser Control panel) differs from the measured value by more than 10%, the software will automatically adjust its optical transmission factor. This compensates for any change in energy transmission, and fine-tunes the calculated fluence value for continual accuracy.

eQC Run Scan Measurement There is an eQC scan type that can be placed like any other scan.

FIGURE 3-9 eQC Scan

To insert an energy measurement into the scan list:

1 Select the eQC tool from the Place/Move Scans window.

2 Click on the video image to place the scan.

The eQC scan is displayed in the Image View window as a bullseye crosshair, and is visually located where the scan was placed on the sample. But when the scan list is run, the stages automatically move to the eQC measurement position, then read and record the energy in situ, on the sample holder.

Like any other scan, the eQC scan can be dragged within the list to change the scan order. After an eQC scan is run, the energy value is saved in the Data field, and can be viewed by clicking the View button in the Data column for the scan. The value is also included when saving an experiment to a file.

eQC Setup Click the Settings line below the eQC line in the Laser Control panel to open the eQC Setup window. This window allows configuration of eQC parameters, calibration of the meter reading, and some service only settings.

FIGURE 3-10 eQC Setup



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eQC Laser Setup The Laser tab of the eQC Setup window allows selection of the Laser Energy level, and the Spot Size to use when reading the energy meter. Once the Laser Energy and Spot Size are selected, both the On Demand mode and eQC scan tool will use the same settings. There are a limited number of Laser Energy levels and Spot Sizes allowed for use by eQC. This ensures the laser is producing enough energy to meet the sensitivity of the energy meter, and helps provide a consistent environment when reading the energy meter. Normally, the meter reading is displayed as energy density, or fluence, but it can also be displayed as raw energy in millijoules.

eQC Calibration A calibration factor is used to compensate for laser energy loss through the window between the sample cell and the energy meter head. To calculate and save the calibration factor:

1 Place the meter head in the eQC sample drawer, and place the interlock defeat into the meter head location at the back of the chamber. Chromium can then read the energy inside the chamber.

2 Remove the interlock defeat, and place the meter head back in its standard location against the chamber window, and let Chromium read it again. The calibration factor is then automatically calculated from the two readings.

3 Save the newly calculated value.

eQC Service Mode Settings The Service Mode tab contains parameters for the eQC meter reading process. These values are visible for reference, but should only be changed by service personnel. These include:

The threshold value at which the meter determines a valid reading.

The time duration for the laser warmup and data taking modes of the process.

The stage locations at which the laser beam will reach the meter head for calibration and for normal run.

All of these are set at the factory, and normally should not need to be changed.

4 Analysis Quick Start

Building SequencesA sequence is built automatically as you place scans into the scan list. When the sequence is run it will move sequentially through the scans listed using the parameters given, both in the scan list itself, and also those parameters set in the run scans dialog.

TriggeringThe laser ablation system can send out a trigger signal to the ICP to coordinate timing between the laser firing and data acquisition. A similar signal can be received from the ICP.

Triggering is different for each combination of laser ablation system, ICP, ICP software, and laboratory needs. In general, you will need to:

1 Connect a triggering cable between the laser ablation system and the ICP.

2 Set up the ICP to receive a trigger from the laser ablation system.

3 Set up the ablation sequence so that there is adequate time for the ICP to complete each sample before the next spot is ablated.

If the system is to be run without any input or output triggers, then both TRIG IN and SYNC OUT should be set to Not Used. In this mode the user is responsible for starting both the laser and the mass spectrometer (MS).

If the MS will supply a trigger, set TRIG IN to either Active HIGH or Active LOW as appropriate. Whichever trigger is used, a delay can be specified between the time when the trigger pulse is received and when the laser first fires at the scan.

If, on the other hand, the laser ablation system is to provide an output signal to cue the ICP to start, then set SYNC OUT to either TTL: Active High/Relay: NC or TTL: Active Low/Relay: NO. Contact Teledyne Photon Machines for information on switching between TTL and switch closure signals for SYNC OUT. A delay may be specified between sending the SYNC OUT signal and firing the laser.


Chapter 4: Analysis Quick Start

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Contact Teledyne CETAC Technologies or Teledyne Photon Machines if you need help with triggering. Triggering guides are available are available on request for some popular configurations.

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