1. GLAST Large Area Telescope:
Gamma-ray Large Area Space Telescope
GLAST Large Area Telescope:
Tracker Subsystem
WBS 4.1.4
5C: Silicon Detector Procurement
Hartmut F.-W. Sadrozinski
Santa Cruz Institute for Particle Physics
University of California at Santa Cruz
Tracker Subsystem Scientist

2. LAT TKR Silicon Detector Procurement
Applicable LAT documents:
Specifications
LAT-DS LAT SSD Technical Specifications
LAT-DS LAT Flight SSD Drawings
LAT-DS LAT Test Structure Drawings
LAT-CR LAT SSD Quality and Reliability Assurance
LAT-TD Testing Procedures for the GLAST LAT SSDs
Test Results
LAT-TD LAT Review of SSD RHA Test Results
LAT-TD Results from Heavy Ion Irradiation (SSD)
LAT-QR Q/A OF THE GLAST LAT SSD: RHA

3. TKR Silicon Strip Detectors (SSD)
GLAST has driven the 6” wafer technology
Area: 8.95 cm x 8.95 cm
Thickness: 400 um, pitch 228 um
Very aggressive specs
(leakage currents, bad strips, dicing)
Complete testing by HPK
GLAST Cut-off
“Skinny”
GLAST Cut-of
“Skinny”
Q/A
Every wafer has flight SSD and test structures (coupons, “cut-offs”)
Cut-off has full length, 8 channel SSD
(“Skinny”) and assorted other detectors
Flight SSD and “Skinny” are marked with same ID#
Cut-offs are used for RHA, long-term testing, glueing, wire bonding, etc.
GLAST Flight SSD

4. TKR SSD RHA at Hiroshima University
RHA and Production Q/A for one SSD from each shipping lot
The LAT SSD Q/A provisions LAT-CR define the irradiations to be performed as part of the procurement process. One irradiation with 60Co per shipping lot has to be performed on coupons made on the same wafers as the flight SSDs, and several critical electrical parameters measured pre- and post-rad.
It turns out that the radiation monitoring has been carried out on 77 production runs and no problem has been found.
Procedures
The monitor sensors were irradiated up to a TID of 10 krad(Si), with a dose rate of 3.8 rad(Si)/s.
Of the 77 test sensors, 21 were biased during irradiation at 150 V. After the irradiation, these monitor sensors were kept under 150 V bias at 20 oC until they were electrically characterized for one week after irradiation. The rest of 56 sensors were not biased during irradiation and the one week annealing period.
Electrical tests performed: leakage current, interstrip capacitance and interstrip isolation

5. TKR SSD Procurement # of SSD for 16 (+2 spare) towers:
4 SSD/ladder*2*4Ladders/tray*18trays/tower*18towers = 10,368
+ spares
+ wastage
+ prototypes
Total Purchase: 11,535
Funding:
INFN/ASI 5,000
Japan 6,535
Prototyping from , use 550 SSD in BTEM/BFEM

6. TKR SSD Delivery Profile

7. TKR SSD Production & Funding Plan
Sep 2003
ASI & Japan
Japan
INFN
“Tested” = Final Production step at HPK

8. TKR SSD Production Reality
| | |2003

9. TKR SSD Procurement: Conclusions
Quality:
Outstanding
Production:
~ per month
Delivery:
2 weeks after purchase possible
Testing:
Flight at HPK and INFN Pisa
Irradiated test structures at Hiroshima U.
“Cut-offs” for testing of assembly steps
Concern:
Funding by ASI in Summer 2003