GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 1 Gamma-ray Large Area Space Telescope GLAST Large Area Telescope: GLAST Large Area Telescope: Calorimeter (WBS 4.1.5) W. Neil Johnson Naval Research Lab Calorimeter Subsystem Manager

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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 3 Programmatic Status  In France the CNES Scientific Program committee issued positive recommendation and re-confirmed the French participation in GLAST.  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.  Management activities have focused on creating CAL WBS, revised plans, schedules, and costs for the development and fabrication of the calorimeter  Interim Design Review held in Paris, June 11 – 13, focused on detailed review of the Swedish and French responsibilities, interfaces, work flow and schedules.  Financial problems in France for this FY have been resolved and, as a result, the PIN photodiode procurement (US) for EM diodes was released.  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.  Completed CAL Subsystem Peer Design Review on July 27.

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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 5 Technical Progress  CsI 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.  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. 13 CsI Crystals from Amcrys-H BTEM PIN diode and flex cable

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 6 Technical Progress (2)  Crystal Detector Elements (CDE) –New baseline for CDE includes optical wrapping (VM2000) attached to CsI crystal rather than applied to structure walls. –Mylar tape on corner bevels holds 4 VM2000 strips. Mylar tape VM 2000 film strip Dual PIN diode Flex cable CsI Crystal Glue

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 7 Technical Progress (3)  PIN Photodiode – CsI Crystal Bonding –Studies of potential bonding material continue at IN2P3 and NRL. –IN2P3 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 CsI with surface preparation. The type of bonding for the EM will be chosen after 12 thermal- vac cycles. A set of photodiodes that are larger than CAL diode will be bonded on CsI 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.

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 8 Technical Progress (4)  Pre Electronics Module (PEM) –Verification Model 2 (VM2) 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. –VM2 will contain 12 CDE and 84 mass dummies –Science performance evaluation before LAT PDR

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 9 Technical Progress (5)  First prototype GCFE1 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, data- acquisition 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.  2 nd Version GCFE2 received last week, has Single-Event Upset hardened registers incorporated  3 rd version GCFE3 with short fixed to be submitted July 28.

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 10 Assembly & Test in Europe  CsI crystals delivered to Sweden at rate of 200 per month. –Starts early. Last crystals delivered ~ 5 months before needed.  PIN photodiodes delivered to France at rate of 600 per 5 weeks. –Delivery rate not a problem for Hamamatsu.  CDE Assembly and Test at rate of ~ 200 per month (~ 6 days per crystal)  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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 11 Module Assembly and Test Schedule Phase Module EMQM, PEM Acceptance14985 Elect Integration Calibration12654 Environmental Pre-ship Verification Margin5588 Total per Module  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.) Duration of assembly and test phases (working days for each Module)

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 12 Assembly and Test Schedule ModulePlanned Module Delivery Date LAT Schedule Integration Date Weeks delivery is early Qual Model (FM A)13 May 0315 Aug 0313 Flight Spare (FM B)03 Jun 0315 Aug 0310 Flight Model 129 Jul 0303 Nov 0314 Flight Model 219 Aug 0303 Nov 0311 Flight Model 327 Aug 0302 Jan 0418 Flight Model 410 Sep 0302 Jan 0416 Flight Model 524 Sep 0315 Jan 0417 Flight Model 608 Oct 0315 Jan 0414 Flight Model 715 Oct 0329 Jan 0415 Flight Model 829 Oct 0329 Jan 0413 Flight Model 912 Nov 0312 Feb 0413 Flight Model 1026 Nov 0312 Feb 0411 Flight Model 1110 Dec 0326 Feb 0411 Flight Model 1224 Dec 0326 Feb 049 Flight Model 1307 Jan 0410 Mar 049 Flight Model 1421 Jan 0410 Mar 047 Flight Model 1504 Feb 0424 Mar 047 Flight Model 1618 Feb 0424 Mar 045 Delivery for integration into LAT –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.  Typical delivery rate: One Module every two weeks. –Plan: FMs arrive at LAT Integration Site 5 to 18 weeks earlier than required. Some margin for slippage.

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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 14 Resources - Power Estimate Power Reserve Analysis 75% of reserve held at LAT level Conditioned Power at 3.3 & 70 V For each AFEE board (4 / Module)

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

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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 17 Issues / Concerns  CAL project is working hard to make up for lost time. Additional personnel are being added in US and France to support engineering development.  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 VM2 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.  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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 18 Backup Material

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

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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 21 Development Program  PEM VM2 Prototype –Mechanical Model w/ 12 CDE and 84 dummy crystals –CDE Performance testing before LAT PDR –Environmental testing completed by Dec ‘01  Front End Electronics –GCFE Test Board – Radiation Testing - Nov ‘01 –VM Board, GCFE + GCRC FPGA –Functional testing with CDE –Radiation testing – Jan ‘02  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

GLAST LAT ProjectDOE/NASA Review of the GLAST/LAT Project, Aug. 14, 2001 W Neil Johnson 22 VM2 & EM Development

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