medipix2-based radiation camera and it's application in relaxd and atlas projects zdenek...

Medipix2-based radiation camera and it's application in RELAXd and ATLAS projects

Zdenek Vykydal

Institute of Experimental and Applied Physics,

Czech Technical University in Prague, Czech republic

www.medipix.cvut.cz

PhD seminar, Řež 26.9.2007

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26.9.2007Medipix2-based radiation camera and it's application

in RELAXd and ATLAS projects 2

OutlineOutline

Introduction to the Medipix2 detector Principles of detection with counting pixel detectors Medipix2 single particle counting chip

USB Read-out interface for Medipix2 chip

RELAXd project 3D interconnect technology High density bumping Through silicon via

ATLAS-Medipix project Detector network structure Background measurement in ATLAS cavern

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Principle of semiconductor Principle of semiconductor single particle counting pixel single particle counting pixel detectordetector

N+ P+

Si

Counter: Particle count

+

AmplifierComparator

000001

Threshold level above

electronic noise No false counting.

Digital integration (counting)

No dark current.

Unlimited dynamic range and

exposure time.

Detected count obeys poissonian

distribution

Bia

s V

olt

age

Com

mon

back

-sid

eele

ctro

de

Pix

ela

ted

front-

side

ele

ctro

de

Pixel electronics

Thresholdlevel

26.9.2007 3Medipix2-based radiation camera and it's application

in RELAXd and ATLAS projects

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Back-side pulse Back-side pulse processingprocessing::Getting information about energy of interacting Getting information about energy of interacting particleparticle

Detector chip

Medipix-2 chip

Bias Voltage

Preamplifier(charge sensitive)

Multichannel analyzer

Energy [channel]C

ount Energy spectrum

E

E

FWHM

Trigger

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Medipix2 detectorMedipix2 detector::SSingle particle counting pixel detectoringle particle counting pixel detector

Medipix2 – MEDical Imaging PIXel detector 2nd

generation

High spatial, high contrast resolving CMOS pixel read-out chip

Array of 256x256 pixels

Pixel size 55x55 m²

Sensitive area of 14x14 mm² (87% of entire chip area)

Amplifier, two discriminators and a 13-bit counter in each pixel cell

Serial or parallel readout at 100MHz

Hybrid technology allows to use different semiconductor sensors

www.cern.ch/medipix

Medipix2 SinglePixels: 256 x 256Pixel size: 55 x 55 m2

Area: 1.5 x 1.5 cm2

Medipix2 QuadPixels: 512 x 512Pixel size: 55 x 55 m2

Area: 3 x 3 cm2

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Bias voltage noise distribution

Back side pulse spectrum

Combined alpha source:241Am + 239Pu + 244Cm

USBUSB 1.1 1.1 interfaceinterface::Realization and general featuresRealization and general features

Serial readout speed: 4 fps (4 Mbits/s) Camera-like size, plug and play, hot swap Fully USB powered Integrated source of variable detector

bias voltage (5 – 100V) Advanced triggering and hardware timer No limit for cable length (various USB

extender types) Back-side pulse monitoring for

spectroscopic applications and triggering Open system architecture - internal

analog and digital interface for "plug-in" PCB modules connection

www.medipix.utef.cvut.cz

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USB Lite USB Lite interfaceinterface


First prototype ready and tested

Single chip 3-side tilable read-out assembly board

Based on USB 1.1 interface

Increased miniaturization

Dimensions: 15 mm x 60 mm

26.9.2007 7

+ Low power consumption (no external source)

+ Portability & flexibility

— Performance limitations

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RELAXd project2005 - 4 months @ NIKHEF, Netherlands

2006/2007 - 6 months @ IMEC, Belgium



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RELAXd projectRELAXd project



RELAXd (High Resolution Large Area X-ray Detector)

Four-side tilable Medipix Quad modules Serial readout of individual Medipix chip

up to 500 MHz Fast serial readout of whole Quad module

up to 3.125 Gbps

Used technologies:

3D Integrated Electronic MicrosystemEdgeless sensor technology2D Pitch adaptation between sensor and readout ASICCMOS ASIC 200 mm wafer thinningThrough silicon vias made by deep reactive ion etchingBGA bumping instead of wire-bondingHigh density Indium bump-bondingMulti-Gbit/s data transmission to the PC

www.nikhef.nl/pub/experiments/medipix

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3D interconnect technology



The Medipix2 chip was designed as three-side tilable to enable the possibility of building detectors with larger sensitive area. Size of the I/O periphery and commonly used wire-bond technique for signal connection limits the tiling possibilities of the device to 2 row stripes. To overcome this limitation it is necessary to:Increase the size of the sensor chip to cover I/O area

use pixels with size of about 65 x 65 µm2 and contacts redistribution (interposer layer or postprocessed metal wiring )

use guardring-less sensor chipUse another technology for connection of the I/O signals

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High density Indium bumping



Process flow:

Under bump metallization (UBM) deposition and patterning at detector and Medipix2 substrate

In material deposition and patterning at detector and Medipix substrate

Flip-chip integration and reflow

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Through silicon via technology



Newly developed technology to interconnect the front side and back side of the processed silicon

wafer

Not application specificLow temperature process (< 250 °C) Via resistances in the range of 20 - 30 m (resistance of conventional wire-bond connection is about 60 m/mm for 25 µm wire)

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ATLAS-Medipix project



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ATLAS-Medipix projectATLAS-Medipix project



Main goal is measurement of the radiation field (especially neutron

field) in ATLAS experiment

MPX01 between ID and JM plug

MPX02 between ID, LARG and JM

MPX03 between LARG and LARG EC

MPX04 between FCAL and JT

MPX05 between LARG and JT wheel

MPX06 between LARG and JT wheel

MPX07 top of TILECAL barrel

MPX08 top of TILECAL EXT. barrel

MPX09 corner between JF cyl. and hexagon

MPX10 cavern wall A or C side

MPX11 cavern wall USA side

MPX12 cavern wall

MPX13 between ID and JM plug

MPX14 between ID, LARG and JM

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Detector network structureDetector network structure2 options:< 40 m ethernet cable< 60 m CERN LVDS cable

Public Ethernet (standard cable)

65m

PC with 2 ethernet

cards and Linux OS

(large HDD for data storage)

26.9.2007 15

PC with Windows OS (up to 8 devices)

Power source20V, 5A


Power source20V, 5A


Power source20V, 5A

Board with switches controlled by 7th USB port. If any of devices failed in any way it can be physically disconnected.

Ethernet switch


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Connection optionsConnection options

USB

Detector

Ethernet cable <40m with optional power wires (40V)

USB - extender

Mounted in UX15

Detector

10 twisted-pairs (20 wires),plus power wires (4-6V),

plus coax for BIAS.<60m

USB interface

Mounted in UX15

LVDS cable

USB extender

LVDS cable solution No feedback (DAC out) – THL-

FBK values will vary after irradiation, impossible to check

Working up to 60m but it needs software adaptation

USB extender solution Maximum length ~40m Tested many times Full capabilities of USB

available (DAC feedback)



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eProtectiveProtectiveBoxBox

240 mm

60 mm

25 mm

USB extender + optional 40V to 5V

converteror

LVDS converter instead of USB

interface

Size of the box was chosed to accomodate

both considered connection options



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eFirst assemblies mounted in First assemblies mounted in ATLAS cavernATLAS cavern

26.9.2007 18

17.8.2007 - first two assemblies (MPX07 and MPX11) were mounted in ATLAS cavern

Remote controll (from the internet) of the devices was established and tested

Continuous data acquisition is running from 19.8.2007 measuring natural background in the ATLAS environment


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MPX 07 deviceMPX 07 device

MPX07 – Top of the TILECAL barel

Horizontal orientation

Fully opened window

Distance of 16m from UX15

Easily reachable

26.9.2007 19

PE

PE + Al

Al

Uncovered

LiF


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MPX 11 deviceMPX 11 device

MPX11 – cavern wall USA side

Vertical orientation

Protected with the black tape

Distance of 18m from the UX15

Easily reachable

26.9.2007 20

PE

PE + Al

Al

Uncovered

LiF


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Thanks a lot for your

attention



medipix2-based radiation camera and it's application in relaxd and atlas projects zdenek...

Documents

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