XAPPER Capabilities, Progress & Plans Presented by: Jeff Latkowski XAPPER Team: Ryan Abbott, Brad...
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Transcript of XAPPER Capabilities, Progress & Plans Presented by: Jeff Latkowski XAPPER Team: Ryan Abbott, Brad...
XAPPER Capabilities, Progress & PlansXAPPER Capabilities, Progress & Plans
Presented by: Jeff Latkowski
XAPPER Team: Ryan Abbott,Brad Bell, and Keith Kanz
May 16, 2006
Work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under
Contract W-7405-Eng-48.
XAPPERXAPPER
JFL 05/16/06
Outline
Current capabilities
Progress since the ORNL HAPL meeting
Planned improvements
XAPPERXAPPER
JFL 05/16/06
Unexposed
Using our first high-quality ellipsoidalcondenser, pure tungsten can be damaged
9000 pulses @~1.5 J/cm2
Significant damage is observed at a fluence of ~1.5 J/cm2
XAPPERXAPPER
JFL 05/16/06
Tungsten test matrix: 10,000 shotson powder met.
1.2 J/cm2
~1.5 J/cm2
XAPPERXAPPER
JFL 05/16/06
Current capabilities
Soft x-ray source:Fluences of 0.25-1.25 J/cm2 ( ~ 10%)~50 ns 10-90% risetimeFWHM spot size is ~400 mRepetition rates ≤10 Hz106 pulses demonstrated, 105 pulse routine
Operational:Fluence measurement conducted using CCD (or CMOS)camera in conjunction with calorimeterVacuum typically ~10-4 torr, then inject xenon for pinchand come up to ~3 mtorrSamples actively heated up to 1000ºC (no active cooling)
Other diagnostics and analysis equipment:In-chamber sample imaging (low magnification)X-ray spectrometerPhotodiodes (fast and integrating)PIE: SEM, TEM, Veeco, x-ray radiography, optical microscopy
~1.0 J/cm2 needed to heat 600C sample to peak surface temperature of 2500C
XAPPERXAPPER
JFL 05/16/06
Since the ORNL HAPL meeting,we have finalized our pyrometer design
Wavelengths of 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6 m selected
Using Avalanche Photodiodes (APDs):Si APDs at 0.6, 0.8 and 1.0 mInGaAs APDs at 1.2, 1.4 and 1.6 mEach will be integrated into an amplifier
Able to reuse SiO2 fiber and feedthrufrom UCSD thermometer
Pyrometer head design uses 3 optics(63, -40 and 63 mm focal length) andis 98.9mm long; 100 m field-of-view
1600 nm
1000nm
800 nm
600nm
500-1700nm
1400nm
1200nm
XAPPERXAPPER
JFL 05/16/06
Calibration will be a big partof our pyrometer effort
Emissivity is both wavelength and temperature dependent
Past work has assumed that (1) = (2)Okay assumption when operating at 0.7, 0.8 mNot a reasonable assumption for a wide range of wavelengths We would see ~2x variation in over our wavelengths of 0.6-1.6 mEmissivity ratios are notconstant with temperature
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Wavelength (m)
Em
iss
ivit
y
1340K
1380K
1430K
1610K
1830K
2040K
2140K
2640K
2650K
Data for polished single crystal tungsten.
XAPPERXAPPER
JFL 05/16/06
Calibration, (Cont'd.)
To enable calibration, we are procuring a high-temperature sample heater (2500C)
Measurements will be taken on the same sample with the pyrometer head sitting in the same orientation to the actual measurement (other than the direction of gravity)
Calibration measurementswill be taken every 100Cfrom 1500-2500C
Post-processing will be usedto determine temperature vs.time from the 6-channel data
XAPPERXAPPER
JFL 05/16/06
Calibration, (Cont'd.)
HeatWave, Inc. is building the sample furnace:Will mount to an 8” conflatWater-cooled flange5-mm-diameter portionof sample viewable at 45
(Very) hot test slatedfor end of June
XAPPERXAPPER
JFL 05/16/06
With the exception of the common opticsand minor items all parts are on order
Ordered:Sample furnaceBandpass filters (2 have arrived and exceed specifications)Longpass filters (to be used as dichroics)Si and InGaAs APDs
To be ordered soon:Optical breadboardOverall enclosureOptical mounts and tubesBK7/SiO2 lensesBatteries (for detectors)
To be fabricated:Light-tight enclosure for detectors (with filter mounts)Top & bottom plates for calibration chamber (in progress)
Arrived/Available:Signal cablingOscilloscopesOptical fiber & feedthru
We are on schedule for system assembly /
checkout in early-July
XAPPERXAPPER
JFL 05/16/06
Other progress and/or improvements
We have completed a forward model of the pyrometer system, including tungsten emission vs. and T, optical losses, and detector response
We have assembled a system to use as the calibration chamber
We are beginning to write procedures for the calibration furnace
Our safety paperwork is being updated
We are beginning to write the pyrometer data processing software
We have refined our CCD processing software (used to determine x-ray fluence) to account for path-dependent filter attenuation
Future exposure campaigns will include mass loss measurements (does this preclude us from putting multiple spots on a sample?)
XAPPERXAPPER
JFL 05/16/06
Summary
Since the last HAPL meeting, we have worked hard to design and procure the new pyrometer:
We expect to bring the pyrometer operational in July
We expect to have new sample exposures, with measured temperatures, in time for the next HAPL meeting
Planned sample priority is: (1) single crystal, (2) VPS tungsten, and (3) powder met. tungsten, (4) silicon carbide
We are holding off (for now) on the fabrication of a new ellipsoidal optic for use on XAPPER that would enable exposure of optical materials (low , big spot)
Right priority?
Back-up slidesBack-up slides
XAPPERXAPPER
JFL 05/16/06
The original thermometer has notworked for us for a variety of reasons
Original system used 200 m fiber with 75 and 40 mm lenses:
Gave a 375 m diameter field of view
XAPPER has a small spot size of~440 m diameter
Gave temperature variations in field of view (a definite no-no for optical pyrometry)
Switched optics to 62 and 150 mm lenses:
Field of view reduced to 83 m
Increased edge temperature to2450 ºC
Reduced field of view cuts signal by 20x, but 46% more solid-angle
Overall signal reduction of 14x
0.0
0.2
0.4
0.6
0.8
1.0
0 100 200 300 400 500
Spot radius (m)
Inte
nsi
ty (
a.u
.)
fieldof
view
Tpeak = 2500ºC
T83m = 2450ºC
T187m = 1510ºC
XAPPERXAPPER
JFL 05/16/06
Original thermometer, (Cont'd.)
Aligning the laser spot to the focused x-ray beam was impossible without manipulation under vacuum installed two-axis motorized gimbal system
Found a signal! Much celebration!
Movie shows field of view with old thermometer head
XAPPERXAPPER
JFL 05/16/06
Original thermometer, (Cont'd.)
We moved onto a new sample to start collecting real data signal was gone!
Discovered that the heavily damaged sample had been reflecting pinch light into the thermometer head
Confirming experiment: blocked EUV beam with a plate of glass and still saw same (visible light) signal
XAPPERXAPPER
JFL 05/16/06
Spectrum from the Astron
0
200
400
600
650 750 850 950 1050 1150
Wavelength (nm)
Inte
ns
ity
(a
.u.)
We have tried various fixes
Look for a dead-zone in the spectrum doesn't appear to be one
Temporal discrimination between pinch and emitted light pinch light persists too long
Vary angles not a real option (can’t get shallower angle; blackbody emission is lambertian, so signal would fall rapidly at steeper angles)
Look at the back side of a thin sample inadequate space
All of these options assume that we have a good signal that gets drowned out by reflected
pinch light. Instead, we see nothing until the material
damages. Suppressing the pinch light won’t fix the
underlying problem.
XAPPERXAPPER
JFL 05/16/06
Original thermometer, (Cont'd.)
3um_cold Front3um_cold Back3um_cold Front3um_cold Back
t (s)
T (
K)
10-9 10-7 10-5 10-3 10-1
3500
3000
2500
2000
1500
1000
Use thin sample (<5 m) to keep material hot for "long" time (milliseconds):
Sit at lower temperature, lose by T4 (12-18x)
Able to count for ~1ms instead of ~100ns, win big (104x)
Unfortunately, the ripples inherent to a thin foil are quite similar to those resulting from surface damage we immediately see reflected pinch light
XAPPERXAPPER
JFL 05/16/06
Original thermometer, (Cont'd.)
Why doesn’t it work for us? Signal strength is just too low:
700/800nm aren’t the best wavelengths for our target temperatures; plus, small spread forces narrow bandpass (10 vs. 40nm) filters, further reducing the possible signal
Simple analysis shows that blackbody emission getting to thermometer head (with Lambertian distribution) is only 1400-2100 p/ns in each band
Emissivity probably ~0.3 and filters transmission is ~50%, so we have200-300 p/ns
Uncoated fiber ends (and possibly optics) result in further reductions
1.E+09
1.E+10
1.E+11
1.E+12
1.E+13
0 500 1000 1500 2000 2500 3000 3500 4000
Wavelength (nm)
Inte
ns
ity
(a
.u.)
600C
1000C
1500C
2000C
2500C
XAPPERXAPPER
JFL 05/16/06
Source designed / built by PLEX LLC
Operates with xenon gas pinch to produce 80-150 eV x-rays
Operation possible at up to 10 Hz for millions of pulses
Condensingoptic
Materialsample
Plasmapinch
The XAPPER experiment is used to studydamage from rep-rated x-ray exposure