Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

X Ray Diagnostics Overview

FAC X-TOD Breakout

October 12, 2006

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Linac-to-Undulator

(227me- beam)

UndulatorHall (175m

e- and beam)

NearExpt.Hall

X-ray VacuumTransport(250m beam)

FarExpt.Hall

e- Beam Dump (40M e- and beam)

(FEE) Front End

Enclosure (29m beam)

Linac e- beam

LCLS Layout at SLAC

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

2-3 mJ (0.3 W) FEL

20 mJ (2.4 W) Spontaneous

3 mJ High energy core E > 400 keV

Raw LCLS Beam Contains FEL and Spontaneous Halo

At midpoint of FEE, FEL tuned to 8261 eV Fundamental, 0.79 nC

0 < E < 10 keV 7.6 < E < 9.0 keV 10 < E < 20 keV 20 < E < 27 keV

20 m

m

Spontaneous halo has rich spectral and spatial structure:

Pulse duration < 250 fs

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Prioritized List of Desired FEL Measurements (to be measured after finding the FEL)

u Total energy / pulse

1 Photon wavelength

Photon wavelength spread

Pulse centroid

Beam direction

f(x,y) Spatial distribution

u,1 Temporal variation in beam parameters

Pulse duration

yx ,yx,

yxyx ,,,

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Prioritized List of Desired Spontaneous Measurements

f(x,y,1) Spatial distribution around 1

1 1st harmonic Photon wavelength

1st harmonic wavelength spread

Beam direction

u Total energy / pulse

u,1 Temporal variation in beam parameters

yx ,

1i/1j Relative 1st harmonic wavelength of undulator i and j

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Codes indicate that damage occurs above melt so choose materials whose doses are a fraction of melt

Maximum dose along the beam line for different materials(under normal illumination assuming fully saturated FEL a la M. Xie)

meters from end of undulator

Dos

e (e

V/a

tom

)(m

axim

um o

ver

827-

8267

eV)

Shown is the maximum dose (over Ephoton=827 to 8267eV)

SiC melted

Si melted

B4C melted

Be melted

Be - 1/50 melt

B4C - 1/12 melt

SiC - 1/9 melt

Si - 5/9 melt

FEEe-

dump

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Candidate detectors pros and consElement Technology Problems

Attenuator Signal reduced, background remains the same

Differential pumped N2 gas Space charge, aperture size

Low Z solids Damage, scattering

CCD Deep depletion Damage, Effect of High E spontaneous, dynamic range

CZT imagers Dental X-ray Damage, Effect of High E spontaneous, dynamic range, resolution

Phosphor coated imagers Phase plate coupled to CCD Damage, Effect of High E spontaneous, dynamic range, resolution, phosphor saturation

Optical coupled Scintillator screen

Camera not in beam Damage, dynamic range, saturation

Indirect Imager Multilayer mirror reflects fraction of beam into camera

Damage, Calibration depends on alignment

Photodiodes, PC diamond Damage, Effect of High E spontaneous, spatial resolution

Florescence Be doped with high z Damage, contamination and background, signal level

Photoelectric Be grid with MCP Calibration, geometry, Effect of High E spontaneous

Thermal Energy to heat Damage, sensitivity

Ion chamber Count ions sensitivity

N2 Photoluminescence Count photons Non-linear space charge, calibration

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

“Direct Imager” x-ray cameras

X-Ray Beam

Visible Imager

Optical Fiber Scintillator

X-ray scintilator with fiber coupled imager

X-ray scintilator with lense coupled imager

X-Ray Beam

Visible Imager

LensScintillator

X-Ray Beam

X-ray sensitive CCD or photodiode array

www.ajat.fi

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Short FEL pulse reveals scintillator saturation

YA

G:C

e Li

ght

Out

put

FEL energy

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Candidate detectors pros and consElement Technology Problems

Attenuator Signal reduced, background remains the same

Differential pumped N2 gas Space charge, aperture size

Low Z solids Damage, scattering

CCD Deep depletion Damage, Effect of High E spontaneous, dynamic range

CZT imagers Dental X-ray Damage, Effect of High E spontaneous, dynamic range, resolution

Phosphor coated imagers Phase plate coupled to CCD Damage, Effect of High E spontaneous, dynamic range, resolution, phosphor saturation

Optical coupled Scintillator screen

Camera not in beam Damage, dynamic range, scintillator saturation

Indirect Imager Multilayer mirror reflects fraction of beam into camera

Damage, Calibration depends on alignment

Photodiodes, PC diamond Damage, Effect of High E spontaneous, spatial resolution

Florescence Be doped with high z Damage, contamination and background, signal level

Photoelectric Be grid with MCP Calibration, geometry, Effect of High E spontaneous

Thermal Energy to heat Damage, sensitivity

Ion chamber Count ions sensitivity

N2 Photoluminescence Count photons Non-linear space charge, calibration

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Diagnostics Occupy Upstream End of the Front End Enclosure (FEE)Slit

Gas Detector

GasDetector

Gas Attenuator

SolidAttenuators

Direct Imager(Scintillator)

Total Energy

FEL Offset Mirror System

Collimator 1SpectrometerPackage

Fixed Mask

Beam Direction

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

FEE Schematic

SolidAttenuator

Gas Attenuator

High-EnergySlit

Start of Experimental

Hutches

5 mm diameter

collimators

Muon Shield

FEL Offset mirror

system

TotalEnergyThermal Detector

WFOV

NFOV

Windowless Gas

Detector

Windowless Gas

Detector

e-

Direct ImagerK Spectrometer

Grating

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Slit and Fixed Mask Define Maximum Beam Spatial Extent

Fixed Mask Slit

Status:PRD doneSCR donePDR doneESD in signatureFDR in preparation

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Gas Detector / Attenuator Conceptual Configuration

4.5 meter long, high pressure N2

section

Differential pumping sections

separated by 3 mm apertures

N2 Gas inlet

3 mm diameter holes in Be disks

allow 880 m (FWHM), 827 eV

FEL to pass unobstructed

N2 boil-off (surface)

Flow restrictor

Green line carries

exhaust to surface

Solid attenuators

Gas detector

Gas detector

Status Attenuator:PRD doneSCR donePrototype doneESD draftPDR in preparation

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Prototype Gas Attenuator runs well at 0-20 Torr

Gas Attenuator prototype pressure control tests

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Gas detectors share differential pumping with the Gas Attenuator

20 Torr~1

Torr

Gas Attenuator

high pressure section

~10-3 Torr

2 m

~0.1 to 2 Torr N2

~10-3 Torr

~10-6 Torr

Gas detector

Optical band pass

filter

Photo tube

Photo diode

Optical ND filters

~20 cm inner

diameternon-specular reflective surface (e.g. treated Al)

LCLS X rays cause N2 molecules to fluoresce in the near UV

Single shot, non destructive, measurement of u

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Gas Detector pressure can be adjusted independently of Gas Attenuator pressure

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Schematic of the gas detector from the ESD

Data Acquisition System

PhotodiodeAvalanche Photo Diode

Cylindrical Vessel

Magnet Coils

Bandpass and ND FiltersCoating

Differential Pumping Section

3 mm aperturesalong beam path

Beam / Gas Interaction Region(~0.1 – 2 Torr N2)

Magnet Power

Supply and Controller

Gas FeedAnd

Pressure Control

APD Electronics

PhotodiodeElectronics

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Overview of physical processes

H.K. Tseng et al.,Phys. Rev. A 17,1061 (1978)

• N2 molecules absorb a fraction of the x-rays by K-shell photoionization, emitting photoelectrons of energy Ex-ray − 0.4 keV

• Ionized nitrogen relaxes by Auger decay, emitting Auger electrons of energy ~ 0.4 keV

• High-energy electrons deposit their energy into the N2 gas until they are thermalized or reach the detector walls

• Excited gas relaxes under the emission of near-UV photons

x-rays

photo e-Auger e-

N2 gas

B

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

A.N. BrunnerCornell University (1967).

Photoluminescence of N2

• N2 has strongest lines in the near UV (between 300 and 430 nm)• Backgrounds in the near-UV are difficult to estimate:

• Effect of recombination of ions at chamber walls?• Effect of electrons hitting the chamber walls?

• We use existing experimental data to estimate the near UV signal:•e.g. measurements made for the Fly’s Eye cosmic ray detector

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

The fluorescence yield per deposited energy depends only weakly

on the energy of the exciting electron

Fluorescence Yield per deposited energy

(a.u.)

Electron energy (eV)

1.5 Torr15 Torr

150 Torr760 Torr

0.85 MeV

8 keV400 eV

(F. Arqueros et al., submitted)

Dependence of the photoluminescence yield on the energy of the incoming electron

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Small magnetic field keeps primary photoelectrons away from walls

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20 25 30

z (cm)

r (cm)

B = 250 Gauss

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20 25 30

z (cm)

r (cm)

without magnetic field

Electron trajectories and energy deposition in N2 at 8.3 keV

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Expected near-UV signal at FEL saturation

0.0

4.0x107

8.0x107

1.2x108

Lambertianreflector

specularreflector

Numberof

Photons

absorber

8.3 keV, 2 Torr, 2.3 mJ, 250 Gauss

0.83 keV, 0.1 Torr, 2.3 mJ, 60 Gauss

0

4x108

8x108

Lambertianreflector

specularreflector

Numberof

Photons

absorber

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Expected near-UV signal for low intensities

8.3 keV, 2 Torr, 1 J, 250 Gauss

0.83 keV, 0.1 Torr, 0.1 J, 60 Gauss

30 cm

2.5”

1 cm recess

0.0

2.0x103

4.0x103

6.0x103

Lambertianreflector

specularreflector

Numberof

Photons

absorber

0.0

2.0x104

4.0x104

Lambertianreflector

specularreflector

Numberof

Photons

absorber

30 cm

x-rays

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Total Energy (Thermal) Sensor Concept

Thermistor(sets operating Top, sensitivity R/T)

FEL pulse

Cu heat sink(sets Tbath)

0.5 mm Si substrate(sets absorption,C and G)

• Radiation-hard absorber • High E halo transmitted • Sensor protected from beam

• Low T operation for high diffusivity ( Speed) and low heat capacity C ( Sensitivity)

Thin low-Z high-G substrate for FEL absorption, thermistor deposited on back side.Temperature rise is proportional to FEL energy, heat flow to cold bath through substrate

Sensor implementation: Nd0.66Sr0.33MnO3 (CMR material) on buffered Si substrate.Cooling in mechanical low-vibration pulse-tube cryocooler

0

10

20

30

40

50

60

-5

0

5

10

15

90 120 150 180 210 240

Nd0.67

Sr0.33

MnO3

sensor on STO-bufffered Si

Res

ista

nce

[k½

]

1/R dR

/dT [%

/K]

Temperature [K]

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

FEL induced Temperature pulse quickly diffuses to sensor side, then dissipates

t = 0 t = 0.1 ms t = 0.25 ms

0

1

2

3

4

5

0 0.05 0.1 0.15 0.2 0.25 0.3

Time [ms]

Del

ta T

empe

ratu

re a

t Chi

p [K

]

Tc200Tc150Tc100

Peak signals are ~1K per mJ of FEL pulse energy as expected for ~mm3 of Si at ~150K.

0.5mm Si

Sensor

FEL

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Sensor temperature maintained by Pulse tube cryocooler

Considerations:1) No liquid cryogens in tunnel2) Low vibrations to reduce microphonic noise and fluctuations in sensor position

frequency [Hz]

103

102

101

100 0 10 20 30 40

ac

cele

rati

on [

µg/

rtH

z]4 1/2” flangePulse tube

Cold head

He gas compressor and rotary valve separated

Low vibrations (SEM compatible)

VeriCold PT: ~5W cooling power at 80K, low vibrations by separating rotary valve.

Sensor position should fluctuate less than ~25 µm beam jitter.

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Calibration of Total Energy Sensor will be maintained through in situ Laser system

Sources of error (according to specs):Variations in laser output E: ±1% rmsAbsolute accuracy of laser output: Not calibratedVariations in optical components: Negligible (below damage threshold)Absolute accuracy of pulse meters: ±5% at 532 nmReflection at Si: 37% at 532 nm (flat surface) roughen,

calibrate

Beam focusAttenuator:Filter wheel

Minilite pulsedNd-YAG laser, 532 nm

Beam splitter on

Gimbal mount

Sensor on Si

Ophir PE-10Pulse meters:3% accuracyIncident beamcalibration

Reflected beam monitoring to assessradiation damage

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Total Energy Error Budget Summary

Calibration errors: <5% (limited by accuracy of pulse meter)

Electronic noise error: <0.1% at saturation<10% at low energies

(depends on excess 1/f noise)

Energy loss error: <2% (limited by electron escape)

Jitter error: <3% (if jitter is as low as specified)

Total error: < 7% at saturation (2 mJ/ pulse)< 7% at 0.2 mJ< 12% at low energies (10 µJ/pulse)Status Total Energy:

PRD doneSCR donePrototype in preparationESD in preparationPDR in preparation

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Total Energy Monitor Prototype

Vacuum chamber: Based on 6-way cross

Refrigeration: Pulse-tube cryocooler

No xy-motion in prototype (yet)XYZ-stage with 5µm steps in z, 3µm in xy

Sensor: Nd0.67Sr0.33MnO3 on Si chip

Surface mount resistor as test heat source, laser soon

Multiple sensors for different FEL conditions can be operated in final design.

To pulse tubeand xy-stage

Weak link Heater

Cu chip mount

Cu-capton-Cuwiring traces

Cu clamps

Sensor

Sensor mount on xy-stage allows ±5 mm field of regard and 40 35 mm2 stay-clear area.

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Direct Imager

Laser Energy Meter

Thermal Detector

Calibration Laser

Beam Direction

Thermal Detector and Direct Imager

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Wide Field of View Direct Imager

Single shot measurement of f(x,y), x, y ,u

Camera

Scintillators

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Photometrics Cascade:512B

The Cascade:512B utilizes a back-illuminated EMCCD with on-chip multiplication gain. This 16-bit microscopy camera’s "e2v CCD97" device features square, 16-µm pixels in a 512 x 512, frame-transfer format. Thermoelectric cooling and state-of-the-art electronics help suppress system noise.

Dual amplifiers ensure optimal performance not only for applications that demand the highest available sensitivity (e.g., GFP-based single-molecule fluorescence) but also for those requiring a combination of high quantum efficiency and wide dynamic range (e.g., calcium ratio imaging).

The Cascade:512B can be operated at 10 MHz for high-speed image visualization or more slowly for high-precision photometry. Supravideo frame rates are achievable via subregion readout or binning.

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Objective: Navitar Platinum 50 Power: 0.1365 NA: 0.060

Run027: Low Energy, All undulator modules, SpontaneousAbsorbed in 5 um YAG, Maximum ~ 20,000 photoelectrons/pixel Full Well: 200,000

Camera: Photometrics 512B

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Objective: Navitar Platinum 50 Power: 0.1365 NA: 0.060

Run030: Low Energy, All undulator modules, FELAbsorbed in 5 um YAG, Maximum ~ 3.7e+8 photoelectrons/pixel Full Well: 200,000

Camera: Photometrics 512B

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Objective: Navitar Platinum 50 Power: 0.1365 NA: 0.060

Run030: Low Energy, All undulator modules, FELAbsorbed in 5 um YAG, Maximum ~ 3.7e+8 photoelectrons/pixel Full Well: 200,000

Camera: Photometrics 512B

Zoomed

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Objective: Linos/Rodenstock Apo-Rodagon-D Power: 0.8 NA: 0.055

Run025: High Energy, All undulator modules, SpontaneousAbsorbed in 50 um YAG, Maximum ~ 10,000 photoelectrons/pixel Full Well: 200,000

Camera: Photometrics 512B

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Camera: Photometrics 512BObjective: Linos/Rodenstock Apo-Rodagon-D Power: 0.8 NA: 0.055

Run026: High Energy, All undulator modules FELAbsorbed in 50 um YAG, Maximum ~ 5.0e+7 photoelectrons/pixelFull Well: 200,000

Zoomed

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Objective: Navitar Platinum 50 Power: 0.1365 NA: 0.060

Run036: Low Energy, First undulator module, SpontaneousAbsorbed in 1 mm YAG, Maximum ~ 1,800 photoelectrons/pixel Full Well: 200,000

Camera: Photometrics 512B

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Experiments Executed at the FLASH VUVFEL to Verify melt Thresholds

FLASH VUV Beamline

Samples:Bulk SiCBulk B4CThin Film SiCThin Film B4CThin Film a-CBulk SiThin Foil AlDiamondYAG

The FLASH photon energy of 39 eV is strongly absorbed in C resulting in extreme energy deposition in small volumes yet multipulse effects in mirrors not yet a problem.

Linac Undulator Gas Attenuator Gas

Detector

C Mirror

Focusing Mirror

Sample

15 single shots at each attenuator setting

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Measured crater depths scale with measured pulse energy

Nomarski picture of ~ 30 micron diameter crater in SiC induced by FEL at 8 x melt

Crater depths, if any, were measured by Zygo interferometry

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

0 20 40 60 80 100

0

10

20

30

40

no damage up to27-33% (0.59-0.66uJ)

Peak

Depth

(nm

)

Cumulative Percentage

Enominal

=

0.4 J 0.8 J

no damage up to73-80% (0.43-0.64uJ)

Data shows a consistent damage

threshold between 120 and 180 mJ/cm2

0 20 40 60 80 100-0.002

0.000

0.002

0.004

0.006

0.008

0.010

0.012

5uJ

2uJ

0.8uJ

GM

De- /

Eno

min

al (V

/uJ)

Cumulative Percentage

0.4uJ

closed symbols: SiCopen symbols: B4C

Data shows that the shot-to-shot pulse energy varies ~linearly between 0 and 200%

•No evidence for surface damage below the melt threshold (~ 90 mJ/cm2 to reach Tmelt, ~130 mJ/cm2 to melt SiC)

Statistical analysis shows damage thresholdMeasured crater depths for 2 low fluence 15 shot series, ordered in increasing depth /

pulse

15 shot series shot-to-shot relative pulse energy measurements ordered in increasing energy / pulse

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

S. Hau-Reige and D. Rutyov postulate multipulse thermal fatigue thresholds ~ 1/10 of melt

Calculate doses for onset of thermal fatigue (D3), to reach melting T (D1), to melt (D2)

Doses below melt but above D3will not visibly damage surface in one shot but material may breakdown after an unknown number of repeated shots in the same place.

Multipulse exposures with eximer laser was inconclusive for Si but data still under analysis

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Channel-cut Si Monochrometer (K-Spectrometer)

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

Diagnostics SummaryInstrument Name

Method Purpose Calibration and Physics risks

Direct Imager

Scintillator in beam SP f(x,y), look for FEL, measure FEL u, f(x,y), x,y

Scintillator linearity,

Scintillator damage,

Must be used with Attenuator,

Attenuator linearity and background

Total Energy Energy to Heat FEL u damage

Gas Detector N2 Photolumenescence FEL u Signal strength,

Nonlinearities

Soft x-ray Spectrometer

Be Reflection grating FEL FEL u Energy Resolution

K Spectrometer Channel-cut Si monochrometer

Measure undulator relative K

Damage,

Signal Strength

Richard M. Bionta

X-TOD Diagnostics bionta1@llnl.gov

October 12, 2006UCRL-PRES-xxxxxxx

ConclusionsUncertanties constrain detector technology

FEL size, shape, and pulse energyDamage thresholds & mechanisms – melted, melt, fatigueShort pulse effects – saturationHigh energy spontaneous background

Avoid placing active detector electronics in beamSingle shot damage thresholds at melt verified at FLASH FELThree technologies chosen for LCLS

YAG Scintillator / camera / attenuator – faint FELGas photoluminescence – indestructibleThermal – least unknowns