GLAST LAT Project Gamma-ray Large Area Space Telescope

GLAST LAT Project Gamma-ray Large Area Space Telescope DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 GLAST Large Area Telescope: Calorimeter (WBS 4. 1. 5) W. Neil Johnson Naval Research Lab Calorimeter Subsystem Manager johnson@gamma. nrl. navy. mil W Neil Johnson

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Calorimeter Subsystem Outline q Programmatic Status q Lehman Review Recommendation Status q Technical Progress q Assembly & Test q Resources q Issues / Concerns W Neil Johnson 2

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Programmatic Status q In France the CNES Scientific Program committee issued positive recommendation and re-confirmed the French participation in GLAST. q A CNES Preliminary Requirements Review will occur in October to authorize the technical approach and French organization. This review will secure the budget for the implementation phase. q Management activities have focused on creating CAL WBS, revised plans, schedules, and costs for the development and fabrication of the calorimeter q Interim Design Review held in Paris, June 11 – 13, focused on detailed review of the Swedish and French responsibilities, interfaces, work flow and schedules. q Financial problems in France for this FY have been resolved and, as a result, the PIN photodiode procurement (US) for EM diodes was released. q Significant efforts have been placed in improving or creating CAL documentation for PDR – required specifications, plans and procedures have been identified and responsible persons have been assigned. q Completed CAL Subsystem Peer Design Review on July 27. W Neil Johnson 3

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Lehman Review Recommendation Status q Sign and implement international agreements – Drafts exist of Mo. A among participating laboratories and of NASA-CNES International Lo. A. – Mo. A has been updated by US and French participants; no apparent action on Lo. A. Successful PRR should permit French signatures. q Organize French efforts and commitment to roles and responsibilities – Done. Documented in Mo. A and WBS. q Develop bottoms up resource-loaded schedule – Done. Delivered to PMCS on 7/20/01. Revisions continue. q Update the cost estimate and assign adequate contingency – Bottoms up costing completed. Contingency analysis on-going. Overall funding and profile are problems. q Resolve PIN diode glue problems – Resources have been applied. Test and selection program identified. Backup solution identified. Tests are continuing. q Define responsibilities for procurement, qualification and testing of ASICs – Done. SLAC designs and tests prototypes. NRL does the rest. W Neil Johnson 4

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Technical Progress q Cs. I Crystals – The first two crystal optical test benches have been completed at NRL and have been shipped to Sweden. – First metrology test bench has been completed in Sweden. – First 24 crystals from Amcrys-H have been received and tested in Sweden. • The crystals were generally as expected although several crystals were slightly out of specification. These out of spec conditions were generally either over sized or incorrect light tapering along the crystal. 13 Cs. I Crystals from Amcrys-H BTEM PIN diode and flex cable q PIN Photodiode – 1 st photodiode delivery expected Aug 15 th. – Flex cable design for connection of PIN to readout electronics has been iterated with mechanical and electrical engineering. W Neil Johnson 5

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Technical Progress (2) q Crystal Detector Elements (CDE) – New baseline for CDE includes optical wrapping (VM 2000) attached to Cs. I crystal rather than applied to structure walls. – Mylar tape on corner bevels holds 4 VM 2000 strips. Mylar tape Cs. I Crystal Glue Dual PIN diode VM 2000 film strip Flex cable W Neil Johnson 6

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Technical Progress (3) q PIN Photodiode – Cs. I Crystal Bonding – Studies of potential bonding material continue at IN 2 P 3 and NRL. – IN 2 P 3 contract with CETIM to model the bonding problem • Rejects hard epoxies • Soft epoxy and silicone are OK. – Bonding Plan • Test soft epoxy & silicone elastomer with primer • A vacuum gap is the backup solution. • Thermal (-30°C to +50°C) cycling in vacuum environment tests between glass and Cs. I with surface preparation. • The type of bonding for the EM will be chosen after 12 thermalvac cycles. A set of photodiodes that are larger than CAL diode will be bonded on Cs. I and ultimately tested for 100 cycles. • Aging tests ( thermal cycling and irradiation) are performed on these glues with particular attention to transparencies • Bonding for FM will be reviewed after completion of test program and experience with EM fabrication. W Neil Johnson 7

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Technical Progress (4) q Pre Electronics Module (PEM) – Verification Model 2 (VM 2) tooling has been designed and is being fabricated – Baseplate design has been modified to meet LAT Grid stiffness requirements. – Preliminary thermal and structural analysis have been completed. – VM 2 will contain 12 CDE and 84 mass dummies – Science performance evaluation before LAT PDR W Neil Johnson 8

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Technical Progress (5) q First prototype GCFE 1 ASIC received at SLAC in June 01 – Contains all functionality • Analog: Multi-gain amplification, shaping, auto-range gain selection, trigger discriminators, five 7 -bit DAC’s • Digital: VHDL synthesized and auto place&routed digital circuits (~10, 000 gates) for configuration/mode registers, write&read state-machine, dataacquisition state-machine & logic, etc. – Digital circuits are fully functional, tested up to limit of test-box, 40 MHz, (f=20 MHz is nominal) – Found capacitor-to-capacitor short of calibration-circuit to gain-selection circuit. Bug discovered in linear capacitor extract software – Analog amplifier and shaper are functional after cut of trace on chip – Single range calibration, charge-amplifier with external gain select, shaping, post-amplification, auto-ranging, acquisition sequence, rail-amplifiers, trigger discriminators are fully operational. Performance tests are in progress. q 2 nd Version GCFE 2 received last week, has Single-Event Upset hardened registers incorporated q 3 rd version GCFE 3 with short fixed to be submitted July 28. W Neil Johnson 9

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Assembly & Test in Europe q Cs. I crystals delivered to Sweden at rate of 200 per month. – Starts early. Last crystals delivered ~ 5 months before needed. q PIN photodiodes delivered to France at rate of 600 per 5 weeks. – Delivery rate not a problem for Hamamatsu. q CDE Assembly and Test at rate of ~ 200 per month (~ 6 days per crystal) q PEM Assembly in France requires 7 weeks per module – – Assembly, Metrology Cosmic muons Environmental: Thermal vac & vibration (TBR) Final test (cosmic muons) Total Processing Time ~ 9 weeks per module W Neil Johnson 10

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Module Assembly and Test Schedule • Duration of assembly and test phases (working days for each Module) Phase Module EM QM, 1 -2 3 -6 7 -16 PEM Acceptance 14 9 8 5 Elect Integration 25 14 10 9 Calibration 12 6 5 4 Environmental 28 17 11 11 Pre-ship Verification 10 7 6 6 Margin 5 5 8 8 Total per Module 94 58 48 43 q The challenge – sustained receipt, assembly, test and delivery of a module every two weeks. – One PEM arrives at NRL every two weeks. – Five Modules in process at once. – One Module ships to LAT Integration Site (SLAC) every two weeks. • (but last Module arrives at SLAC five weeks before required date. ) W Neil Johnson 11

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Assembly and Test Schedule – Plan: FMs arrive at LAT Integration Site 5 to 18 weeks earlier than required. • Some margin for slippage. W Neil Johnson LAT Schedule Integration Date Weeks delivery is early Qual Model (FM A) 13 May 03 15 Aug 03 13 Flight Spare (FM B) 03 Jun 03 15 Aug 03 10 Flight Model 1 29 Jul 03 03 Nov 03 14 Flight Model 2 19 Aug 03 03 Nov 03 11 Flight Model 3 27 Aug 03 02 Jan 04 18 Flight Model 4 10 Sep 03 02 Jan 04 16 Flight Model 5 24 Sep 03 15 Jan 04 17 Flight Model 6 08 Oct 03 15 Jan 04 14 Flight Model 7 15 Oct 03 29 Jan 04 15 Flight Model 8 29 Oct 03 29 Jan 04 13 Flight Model 9 12 Nov 03 12 Feb 04 13 26 Nov 03 12 Feb 04 11 Flight Model 11 10 Dec 03 26 Feb 04 11 Flight Model 12 24 Dec 03 26 Feb 04 9 Flight Model 13 07 Jan 04 10 Mar 04 9 Flight Model 14 21 Jan 04 10 Mar 04 7 Flight Model 15 04 Feb 04 24 Mar 04 7 Flight Model 16 – Instrument integration schedule specifies required Ready For Integration (RFI) dates. – RFI rate: Two Modules every two weeks. • Too much work in parallel, so we’ll start earlier and stretch deliveries. q Typical delivery rate: One Module every two weeks. Planned Module Delivery Date Flight Model 10 Delivery for integration into LAT Module 18 Feb 04 24 Mar 04 5 12

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Resources - Mass Estimate Mass Reserve Analysis 90% of reserve held at LAT level W Neil Johnson 13

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Resources - Power Estimate Conditioned Power at 3. 3 & 70 V For each AFEE board (4 / Module) Power Reserve Analysis 75% of reserve held at LAT level W Neil Johnson 14

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Resources - Cost Estimate W Neil Johnson 15

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Cost Comparison w/ Proposal W Neil Johnson 16

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Issues / Concerns q CAL project is working hard to make up for lost time. Additional personnel are being added in US and France to support engineering development. q Near term schedule to CDR will be a challenge. Critical near term milestones include – Determination of the PIN diode bonding solution and verifying its ability to meet the performance and environmental requirements. – Completion of VM 2 prototype, demonstrating science performance (before PDR) as well as mechanical design verification (post PDR). – Completion of GCFE analog ASIC performance testing and obtaining completely functional parts for EM fabrication. – Completion of EM fabrication and test program prior to CDR. q Revised CAL cost and schedule have just recently (7/20) been submitted to SLAC. – CAL funding is insufficient and profile is not optimal. Resources lost in FY ’ 02 reappear too late (FY ’ 04) to be of much use. – More iterations are required – Environmental test plan needs more consideration. • Cost issues • Over-testing issues W Neil Johnson 17

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Backup Material W Neil Johnson

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Test Matrix W Neil Johnson 19

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Thermal Simulation of Bonding to Cs. I • Thermal (-30°, 20°) simulation of constraints on different glues curing at 20°C by CETIM W Neil Johnson 20

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Development Program q PEM VM 2 Prototype – Mechanical Model w/ 12 CDE and 84 dummy crystals – CDE Performance testing before LAT PDR – Environmental testing completed by Dec ‘ 01 q Front End Electronics – GCFE Test Board – Radiation Testing - Nov ‘ 01 – VM Board, GCFE + GCRC FPGA – Functional testing with CDE – Radiation testing – Jan ‘ 02 q Engineering Model (EM) – Form and function of flight units, commercial grade parts where required, fully populated PEM – Functional testing – Environmental testing – Beam tests – Delivered to SLAC for T&DF, software development W Neil Johnson 21

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 VM 2 & EM Development W Neil Johnson 22

GLAST LAT Project DOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 Current Estimate vs Funding W Neil Johnson 23