Transcript Section 2.B - Tracker Radiation

GLAST LAT Project
March 24, 2003
GLAST Large Area Telescope:
Gamma-ray Large
Area Space
Telescope
Tracker Subsystem
WBS 4.1.4
2B: Radiation Evaluation-Testing
Hartmut F.-W. Sadrozinski
Santa Cruz Institute for Particle Physics
University of California at Santa Cruz
Tracker Subsystem Scientist
[email protected]
2B
Tracker Peer Review, WBS 4.1.4
1
GLAST LAT Project
March 24, 2003
LAT TKR Radiation Overview
•
Radiation Levels are given in:
– 433-SPEC-0001 GLAST Mission System Specification, CH 07
– LAT-SS-01165 TID Self-Shielding of the GLAST LAT TRK
•
Applicable LAT documents:
– LAT-SS-00152 Level-4 Electronics requirements
– LAT-DS-00011 LAT SSD Technical Specifications
– LAT-TD-00673 Constraints on the Temperature of TKR SSD
– LAT-TD-00401 LAT EE Parts List
– LAT-SS-00169 TKR Front-End (GTFE) Specification
– LAT-SS-00170 TKR Readout Controller (GTRC) Specification
2B
Tracker Peer Review, WBS 4.1.4
2
GLAST LAT Project
March 24, 2003
LAT TKR Radiation Overview
– Test plans:
– LAT-CR-00082
– LAT-TD-00085
– LAT-PS-01325
Test Results
– LAT-TD-00086
– LAT-TD-00128
– LAT-QR-01078
– LAT-TD-00333
– LAT-TD-01172
– LAT-TD-01632
•
2B
LAT SSD Quality and Reliability Assurance
Testing Procedures for the GLAST LAT SSDs
Radiation Test Plan for the LAT TKR ASICs
LAT Review of SSD RHA Test Results
Results from Heavy Ion Irradiation (SSD)
Q/A OF THE GLAST LAT SSD: RHA
SEE Test of the LAT TKR Front-End ASIC
LAT TKR Readout Controller ASIC SEE Test
LAT TKR Frontend ASIC SEE Test
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
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Radiation Levels: TID
TID is caused by Charged Particles Trapped in SAA
100000
Full dose - Spherical shield
550 km 28° circular orbit
5-year mission - Solar Minimum
•
Shielding helps!
•
Front: Heat blanket, ACD
– Shielding 2 g/cm2 eliminates all electrons
Back: Mass of LAT
- Cuts TID by half
1000
Electrons
Bremsstrahlung
Protons
•
Total
100
10
1
0.01
0.1
Depth (g/cm2 Al)
1
10
Total Dose at the Center of Solid Aluminum Spheres
GLAST: I=28.5 deg, 550 km circular orbit
•
•
1.0E+06
Values Do Not Include Design Margins
Total Dose (rads-Si/5 years)
5-year mission dose (rads)
10000
1.0E+05
1.0E+04
•
1.0E+03
Expected 5Y TID < 0.8 kRad ( low ! )
Design 5Y TID = 4 kRad
(5x Engineering Margin)
Only in outer SSD layers
& for ASICS on outside
Majority of TKR much less
Testing TID = 10 kRad
1.0E+02
1
2B
10
100
Aluminum Shield Thickness (mils)
1000
10000
Tracker Peer Review, WBS 4.1.4
4
GLAST LAT Project
March 24, 2003
Radiation Levels: Heavy Ions
SEE Effects due to Galactic Cosmic Rays and Solar Particle Events
•
Galactic Cosmic Ray Spectrum
550km Circular, Inclination 28.5 Deg., 1 Year, 100 mils Al Shielding
1.E+07
Solar Maximum
1.E+06
Solar Minimum
1.E+05
1.E+04
Integral Flux (#/cm²)
1.E+03
•
1.E+02
1.E+01
1.E+00
1.E-01
1.E-02
1.E-03
1.E-04
•
1.E-05
1.E-06
1.E-07
1.E-01
1.E+00
1.E+01
1.E+02
LET (MeV*cm²/mg)
1.E+03
Data from CREME96
Worst Case Solar Particle Event
550km Circular, Inclination 28.5 Deg., 100 mils Al Shielding
1.E+00
Worst Day
1.E-01
Peak 5 Minute
1.E-02
•
1.E-03
Integral Flux (#/cm²/s)
1.E-04
1.E-05
1.E-06
High energy particles due to
Geomagnetic cut-off:
Shielding less effective!
GCR:
- For LET > 2 : F(5Y) ~ 5/cm2
- LET < 28 MeV/(mg/cm2)
SPE:
- For LET > 5 : F(5Y) ~ 5/cm2
(worst day/4)
- LET < 100 MeV/(mg/cm2)
Rates very low, but SEE effects
potentially destructive
1.E-07
1.E-08
•
1.E-09
1.E-10
1.E-11
1.E-12
GLAST Specs:
evaluate for LET < 37 MeV/(mg/cm2)
1.E-13
1.E-01
2B
1.E+00
1.E+01
LET (MeV*cm²/mg)
1.E+02
Tracker Peer Review, WBS 4.1.4
1.E+03
Data from CREME96
5
GLAST LAT Project
March 24, 2003
Radiation Effects on TKR Parts
•
Use parts on the accepted parts list of GSFC as much as possible
•
New Part: Polyswitch re-settable device (3,456 in LAT)
- Do ~ 100 kRad TID test ? NO (Parts are treated with 20 MRad
during polymerization to enhance cross-linking!)
- Mitigates SEL risk!
•
SSD: (9,216 in LAT)
- SEE effects tested; no effects observed, as expected
- TID (ionizing) tested with 60Co: part of Q/A at Hiroshima U.
- Proton fluence generates leakage current and limits operating
temperature
•
ASICs: (1,152 GTRC, 13,824 GTFE in LAT)
- SEE effects important (SEU and SEL): test plan & results
- TID (ionizing): test plan & results
2B
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6
GLAST LAT Project
March 24, 2003
Radiation Effects on TKR SSD
•
•
•
Displacement damage due to trapped protons increases leakage current
DI ~ a*Vol*F
Noise in frontend amplifier increases with leakage current
ENC(DI) ~ (DI*t)0.5
Exponential temperature dependence of DI limits operating temperature:
Data
apply to
top TKR
layers
only
2B
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7
GLAST LAT Project
March 24, 2003
Radiation Hardness Assurance on ASICs
•
•
•
•
Testing done by INFN Padova collaborators
- SEE testing at INFN Legnaro tandem Van der Graff facility ()
- TID testing at INFN Legnaro 60Co source
- We have done 2 SEE runs, 1 TID irradiation with fully functional
pre-production prototype TKR ASICs
All LAT ASICs are fab’ed in epitaxial 0.5um Agilent CMOS
- TID not a problem, SEL Threshold > 56 MeV/(mg/cm2)
TID Test Plan for each of the 5 lots of GTFE, 1 lot of GTRC
- 7 parts each mounted on mini-MCM with 2 GTRC
- TID = 10 kRad in 4 steps
- Measure power, gain, noise rate and functionality
SEU Test Plan for of each of the 5 lots of GTFE, 1 lot of GTRC
- 2 parts each mounted on mini-MCM with 2 GTRC
- Heavy ions with LET from 8 (Si) to 83 (Au) MeV/(mg/cm2).
- Measure Single Event Upset(SEU), Single Event Functional Interrupt
(SEFI) and Single Event Latch-up (SEL) cross sections
2B
Tracker Peer Review, WBS 4.1.4
8
GLAST LAT Project
March 24, 2003
TID Test Results on TKR ASICs
•
Testing by INFN Padova (R. Rando, D. Bisello, J. Wyss et. al.)
- Irradiate both GTRC and GTFE pre-production prototypes
- Use mini-MCM and DAQ set-up:
•
After TID of 10 krad for GTFE, 20 krad for GTRC
- Power dissipation did not change
- Gain stable
- Noise rate under control
- GTRC and GTFE function at 20MHz
2B
Tracker Peer Review, WBS 4.1.4
9
GLAST LAT Project
March 24, 2003
SEE Test Results on TKR ASICs
•
Testing by INFN Padova (R. Rando, D. Bisello, J. Wyss et. al.)
- Irradiate both GTRC and GTFE pre-production prototypes
- Fluence from GTRC Test:
Ion
Energy
species (MeV)
LET
(MeVcm2/mg)
Range
(um)
107
54.7
28.4
8.6
38.8
81.7
28
34
62
31
23
Ag
Ni
28
Si
79
Br
197
Au
58
•
•
•
•
•
271.88
236.13
162.17
246.84
275.68
Total
fluence
(ions/cm2)
6106
1107
8107
8106
5106
Dose
(krad)
5
5
10
5
6
Dose after
1st half
(krad)
2.5
7.5
15
22.5
28
Dose at the
end
(krad)
5
10
20
25
31
NO SEL observed  Upper limit on expected rate of Latch-up
SEU cross sections sensitive to layout details as expected
Rockett cell proves to be SEU hardened
No TID effects
Radiation Testing well in hand
2B
Tracker Peer Review, WBS 4.1.4
10
GLAST LAT Project
March 24, 2003
SEE Test Results on TKR ASICs cont.
•
 (SEU cm2 / bit ion)
1E-6
1E-7
REG 0->1
1E-8
Very consistent results wrt. to
previous data on test chips
- Cross sections different
for 0 —> 1 and 1 — > 0 etc
SYNC 0->1
REG 0->1 [6]
trend [6]
1E-9
0
10
20
30
40
50
60
70
80
90
LET (MeV cm2 / mg)
•
Cross section threshold:
~ 5-8 MeV/(mg/cm2)
•
SEL Upper Limit
< 10-6 cm2 /GTRC
2B
Tracker Peer Review, WBS 4.1.4
11
GLAST LAT Project
March 24, 2003
SEE Test Results on TKR ASICs cont.
•
Communication errors and SEFI error cross sections and upper
limits for SEL for the entire GTRC.
- The Weibul fit  = S*(1-e-(LET-THR)/W)
gives S = 4*10-6, THR = 5 - 8, W = 40-48.
Weibull
Parameters
S
[cm2]
THR
[MeV/(mg/cm2)]
W [MeV/(mg/cm2)]
Errors/5Y [H.I.]
per GTFE
Total errors/5Y in
any GTFE [H.I.]
Errors/5Y [SPE]
per GTFE
Total errors/5Y in
any GTFE [SPE]
•
•
2B
SEL
SEU
SEU
SEU
SEU
(U.L)
(COM_Err)
(TRG)
(CHN)
(CAL)
2
2
2
2
[cm /GTFE] [cm /GTFE] [cm /GTFE] [cm /GTFE] [cm2/GTFE]
8*10-7
4*10-6
1.2*10-5
2*10-5
1.5*10-5
8
8
8
8
8
25
9
27
76
29
<1.8*10-8
2.2*10-7
2.5*10-7
1.5*10-7
2.9*10-7
< 2.5x10-4
0.003
0.0035
0.002
0.004
<3.8*10-7
1.9*10-6
3.6*10-6
2.9*10-6
4.3*10-6
< 0.005
0.026
0.05
0.04
0.06
SEL Probability < 0.5 % for entire TKR in 5 years
SEU Probability ~ 1% for entire TKR in 5 years
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
SEL Testing: Using the right H.I. Range
•
•
•
•
Single Event Upset (SEU) is essentially a surface phenomen:
- Large charges in the gate flips the bit, no special H. I. range
Single Event Latch-up (SEL)
- Caused by parasitic transistor inside the bulk
- Epitaxial structures should reduce charge collection
- Range of Heavy Ions has to exceed the charge collection distance
Collection Distance
- A.H. Johnston “an ion range that is approximately twice the
dimension of the epitaxial layer thickness is generally adequate”.
For our 6um epi process this means 17 um required range.
- J. Howard et al. find charge collection distance of 26 um for high
energy heavy ions in 7 um epitaxial structures.
• ESA/SCC Basic Specification No. 25100: ion range > 30 um .
Heavy Ion Range for LET = 37 MeV/(mg/cm2)
- LNL Legnaro
(Br)
31um LAT TKR Preference
- BNL
(Br)
39um
- TAMU
(Ag) 130um
GSFC Rad Branch Preference
2B
Tracker Peer Review, WBS 4.1.4
13
GLAST LAT Project
March 24, 2003
TKR Radiation Evaluation: Conclusions
•
SSD:
- Radiation issues well understood; used to Q/A the lots (Hiroshima)
- Increase in leakage current not expected to diminish TKR
performance as long as the temperature is controlled to <30C
•
ASICs:
- Require radiation testing for each of the lots (5 GTFE, 1 GTRC)
- Radiation testing well in hand at INFN Padova
- Expected TID and SEE risk very small
- SEL mitigation from polyswitch resettable devices
•
Concern:
- Schedule: ASIC radiation testing has to start in April, yet test plan
has not been signed off by GSFC.
- Cost: New requirements could introduce schedule, cost and manpower problems. We are talking with GSFC rad group …
2B
Tracker Peer Review, WBS 4.1.4
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