1. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 1 Gamma-ray Large Area Space Telescope GLAST Large Area Telescope ISOC Peer Review Section 7.1 Pre Launch Operations and Calibrations Eduardo do Couto e Silva Manager of the Science Verification Analysis and Calibration Department of I&T Subsystem

2. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 2 Outline Connection between I&T/SVAC and ISOC/SOG I&T/SVAC Requirements Examples of I&T/SVAC activities –Lessons Learned from I&T/SVAC –Examples of preliminary data analysis Summary

3. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 3 Connection between SVAC/I&T and SOG/ISOC The Science Verification Analysis and Calibration (SVAC) Department of the I&T subsystem will gradually transition into the Science Operations Group of the ISOC. The main responsibilities of the SVAC Department are Coordinate Data Analysis for Science Verification Perform final pre launch calibrations Perform first in-flight calibrations prior to hand off to ISOC/SOG (see talk in section 7.2) Deliver calibration products to ISOC/SOG

4. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 4 I&T Pre Launch Experience with EM The Science Operations Group (SOG) has been recently created and does not yet have all of its documentation in place In this talk we will present an overview of the I&T/SVAC experience using the Engineering Model (EM) test as an example of the activities that will be performed by the SOG during mission operations The lessons learned on following items will be discussed –Documentation –Data Processing –Operations –Calibrations –Data Analysis

5. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 5 LAT Performance Specifications Science Verification, Analysis and Calibration (SVAC) Plan CalibrationData AnalysisScience Verification GLAST LAT SVAC Plan LAT-MD-00446 LAT-SS-00010 Science Requirement Document 443-SRD-00010 ACD, CAL, TKR Specifications LAT-SS-00016, LAT-SS-00017 LAT-SS-00018, LAT-SS-00152, LAT-SS-00210 Level II Levels III and IV Level III Science and Calibration requirements from Subsystems Plans were captured in LAT-MD-00446

6. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 6 SVAC Plans and Technical Documents SVAC Plans and Technical Documents Engineering Model EM LAT LAT-MD-00573 LAT-TD-01588 LAT-TD-00582 LAT-TD-00578 LAT-TD-00571 LAT-MD-00576 LAT-MD-00581 LAT-MD-00577 Hardware Test Plan/Results Calibrations Simulations Databases Interfaces LAT-MD-00575 LAT-TD-01590 SAS responsibility LAT-TD-00580 LAT-TD-00573 LAT-MD-00446LAT-MD-01587LAT-MD-00613 Co-owned with Systems Engineering Co-owned with Project Scientist LEVEL III LEVEL IV LAT-TD-01593 LAT-TD-01340 LAT-TD-01595 Co owned with Instrument Operations Center Contributed Manpower Plan Existing docs are shown in red boldface At this time we are reviewing the EM documents and lessons learned to produce the necessary documentation for the LAT Integration

7. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 7 Level III Documents - Contents LAT-MD-00446 - SVAC Plan –Instrument Calibrations –SVAC Compliance –Pre Launch Test Matrix –Post Launch Test Matrix LAT-MD-01587 – SVAC Test Requirements Plan –Hardware Required –Flight Software Required –Test Configuration –EGSE Required –MGSE Required –Test Software –Support Instrumentation –Test Data Record –Data Format –Test Products –Analysis Activities –Environmental Conditions –Test performance Procedures –Facility Requirements –Quality Program Performance Requirements –System Assurance Requirements –Test Equipment Calibration Co owned with Systems EngineeringCo owned with Project Scientist LAT-MD-00613 - SVAC Plan –Engineering Model TKR,CAL,SAS –Calibration Unit ACD,TKR,CAL,SAS,IOC –LAT ACD,TKR,CAL,SAS,IOC Contributed Manpower Plan

8. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 8 Level IV Technical Documents – Contents Test Plan/Results –LAT-MD-00573 – SVAC EM Plan Describes the hardware data taking configurations, infrastructure needed for calibrations, calibration types, data analysis requirements. Run time estimation using MC simulation –LAT-MD-01593 – SVAC Results from the Engineering Model Test Describes the results and how requirements were met Calibrations – LAT-TD-01588 – Calibration Algorithms for the Engineering Model Describes the calibration algorithms developed in conjunction with SAS and subsystems Simulations – LAT-TD-00582 – EM Geometry for the Monte Carlo Simulation Describes the geometry used in the simulation, includes table to translate nomenclature from software developers to engineers and also contains traceability Database – LAT-TD-00578 – SVAC Database for the Engineering Model Describes the table schema and how a web based engine will allow access to a subset of calibration data for the purpose of tracking changes in time. Interfaces –LAT-TD-00571 – SVAC/SAS Interface Control Document Describes the responsibilities between SAS and SVAC for data analysis (Statement of work) –LAT-TD-01340 – SAS Calibration Infrastructure Describes SAS calibration infrastructure that holds the primary calibration data Using Engineering Model as an example

9. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 9 Documentation – Lessons Learned EM Lessons Learned –Lots of documents and not enough time for people to read them (i.e., less than optimal feedback from subsystems) –In some cases ideas were discussed in details but were not mature enough to be implemented (e.g. EM database) –Difficult to keep up with update needs given the manpower limitations within I&T For SOG –Documentation shall be kept at a level that is adequate to guide planning while allowing for technical reviews –Interfaces need more attention and shall be more detail oriented

10. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 10 Data Analysis Chain ROOT tree Files (digi) SAS/ONLINE Converter ROOT tree Files (recon) SAS Recon “GENERAL” USER Online Analysis tools online scripts Calibration Constants Calibration scripts ROOT ntuple files IDL Structures SAS Converter SAS User Interface EBF EM In the future the FSW Filter will go in here

11. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 11 Data Processing – Lessons Learned EM Lessons Learned –Data transfer was tedious and was partially automated –Reprocessing of data occurred more often than expected –The Information about datasets necessary for data analysis was not available through a user friendly interface (despite our planning!) For SOG –Fix communication problems between interfaces and devise system tests to minimize needs to reprocess data –Investigate with SAS how to automate Data Processing –Create better requirements to implement database queries

12. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 12 Calibrations – Lessons Learned EM Lessons Learned –In some cases procedures were developed on the fly (not a serious impact since we did not have to deal with many software versions) –I&T was not directly involved in all calibrations For SOG –Implement better configuration control of data and procedures to produce data –Develop sufficient expertise within SOG to handle all possible calibrations –Understand better requirements for interfaces with FSW

13. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 13 Operations – Lessons Learned EM Lessons Learned –In some cases it was difficult to determine the data taking configuration –Not all information was available during data taking –New configurations were added during the data taking period without adequate planning For SOG –Implement better user guides and operator training –Develop a process to critically review operational procedures and to address unscheduled configuration changes –Understand interface with FSW

14. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 14 EM Ground Calibration Set-up CALTKR Gammas:66% 17.6 MeV 34% 14.6 MeV, FWHM = 1.5 MeV + lots of electrons Cosmic Background Electrons are produced by gamma conversions in the iron shield in front of the accelerator Beam pipe Not a monochromatic beam!

15. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 15 CAL Energy Spectrum CAL Energy Spectrum 1 10 100 1000 400 300 200 100 0 1 10 100 1000 2500 2000 1500 1000 500 0 Photon Source OFF Photon Source ON Energy (MeV) Mostly photons From Gary Godfrey Preliminary

16. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 16 Source Calibration From Gary Godfrey Expect two energy lines Preliminary

17. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 17 Flux Measurement Top TKR face Extrapolation to Photon Source EM Rec Direction cosine In 0.02 bins 10% error is dominated by the knowledge on the BGO position 9% of the of photons produced by the source are measured by the EM From Gary Godfrey Preliminary

18. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 18 Energy Measurement ROOT tree Files (digi) Raw spectrum of individual crystals Calibration Constants Perform Calibrations C14,C15,C16,C18 on each crystal Operational Settings Perform C18,C19,C20,C22,C23,C24 to establish baseline for data taking ROOT tree Files (recon) Produce Energy Calibrated Spectrum using all crystals ROOT ntuple files Use Data Analysis Cuts and VDG Flux Calibration to obtain final spectrum Data Analysis Calibrations IDs are described in LAT-MD-00446

19. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 19 EM Energy Spectrum (VDG DATA) Event selection: nTkrTracks>=1 && zDir 4MeV Expected  Spectrum Delta function (17.6 MeV) Breit-Wigner (mean 14.5, width=1.5MeV ) Energy (MeV) From Xin Chen Preliminary

20. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 20 Energy Spectrum (VDG MC) Events converted in top layer of Tracker only From Xin Chen Event selection: nTkrTracks>=1 && zDir 4MeV Expected  Spectrum Delta function (17.6 MeV) Breit-Wigner (mean 14.5, width=1.5MeV ) Energy (MeV) Preliminary

21. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 21 Data Analysis – Lessons Learned EM Lessons Learned –Expected experimental backgrounds were not thoroughly studied prior to the test –Some algorithms and pieces of the offline software were not validated prior to the data taking period –Calibrations took longer than expected For SOG –Develop with SAS, I&T and LAT Collaboration tools for instrument and sky simulations to address needs of first- year operations –Develop better communications across interfaces and sharpen calibration requirements

22. GLAST LAT Project ISOC Peer Review - March 2, 2004 Document: LAT-PR-03213-01 Section 7.1 Pre-launch Operation and Calibration 22 Summary Lessons Learned –The I&T/SVAC group will revisit all EM technical issues to ensure a successful LAT integration. I&T/SVAC will participate in the planning process to build the infrastructure required for the SOG during the I&T integration Concerns –More discussions and planning are needed to address how the operational procedures and calibrations exercised during Integration will be adapted to the Flight Software environment (not present during EM)