1. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 1 Gamma-ray Large Area Space Telescope High Energy Gamma Physics with GLAST Monica Pepe INFN Perugia on behalf of the GLAST-LAT Collaboration 32nd International Conference on High Energy Physics August 16-22, 2004, Beijing, China

2. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 2 Use of high resolution and reliable particle detectors is now possible in space after long and successful experience in particle physics Study of the origin of the Universe and its evolution : strong connection between Astrophysics and HEP with many areas of collaboration GLAST : Motivations and Goals GLAST is a partnership of HEP and Astrophysics communities sharing scientific objectives and technology expertise:  Designed to use very performant particle detectors order of magnitude inprovement in sensitivity and resolution wrt previous missions  Sky survey in the 10 keV – 300 GeV energy range ( poorly observed region of the electromagnetic spectrum )

3. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 3 The GLAST Mission Spacecraft GLAST Burst Monitor ( GBM ) 10 keV - 25 MeV (correlative transient observations) Large Area Telescope ( LAT ) 20 MeV - >300 GeV High Energy Gamma Ray observatory: 2 instruments  Observe, with unprecedented detail, sites of particle acceleration in the Universe  Explore nature highest energy processes (10 keV – >300 GeV)  Answer to important outstanding questions in high energy astrophysics raised by results from EGRET

4. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 4 GLAST science capabilities 0.01 GeV 0.1 GeV 1 GeV 10 GeV 100 GeV 1 TeV Cosmic ray acceleration Active Galactic Nuclei Unidentified sources Pulsars Gamma Ray Bursts Dark matter (A. Morselli talk) Solar flares

5. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 5 Predicted sensitivities to a point source: EGRET, GLAST, ARGO, AGILE, Milagro : 1yr survey Cherenkov telescopes: 50 hours on source Covering the Gamma-Ray Spectrum  Broad spectral coverage is crucial for studying and understanding most astrophysical sources  GLAST and ground-based experiments cover complementary energy ranges  Performance: wide FOV and alert capabilities for GLAST / large effective area and energy reach for ground-based  Overlap: between GLAST and Cherenkov allows energy and sensitivity calibrations for ground-based instruments in the 50-500 GeV energy range GLAST goes a long way toward filling in the energy gap between space-based and ground-based detectors. There will be overlap for the brightest sources. AGILE

6. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 6 GLAST Survey: ~10000 sources in 2 years 3 rd EGRET Catalog (1991-2000) (~ 300 sources) Sky Map

7. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 7 Counting stats not included. Cygnus region (15 0 x 15 0 ), E  > 1 GeV GLAST 95% C.L. radius on a 5  source, compared to a similar EGRET observation of 3EG 1911-2000 170/271 3 rd EGRET Catalog sources still unidentified  provide source localization at the level of arc-minute  determine Energy spectra over a broad range and Time variability on many scales correlate  -ray detections with sources in other wavebands and discriminate between source models Identifying Sources GLAST high angular resolution and sensitivity:

8. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 8 AGN signature vast amounts of luminosity (10 49 erg/s) and energy (spectra extending to GeV and TeV regions) from a very compact central volume high variability on a time scale <1 day highly-collimated relativistic particle jets Active Galactic Nuclei EGRET discovery: AGN are bright and variable sources of high energy  -rays Hypotesis: relativistic plasma ejected from accreting super-massive black holes (10 6 - 10 10 solar masses)

9. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 9 AGN Physics with GLAST  Increase the number of known AGN from ~80 to ~5000  Distinguish leptonic (SSC/ECS) and hadronic (pp / p  ) models of jets by detailed spectra studies of emitted gammas  Multiwavelenght analysis combining timing and spectral information to determine acceleration and emission sites in the jet Study the redshift dependence of cutoff in the  -ray spectra at large z to probe interaction with extragalactic background light (EBL) Determination of EBL may help to distinguish models of galaxy formation Integral Flux (E>100 MeV) cm -2 s -1

10. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 10 most distant and intense sources of high energy  -rays cosmological distances (afterglow redshift up to z=5) isotropic distribution in the sky transient signal ~ 100  s time scale EGRET: few statistics @ E>50 MeV, no temporal studies at high energies (large dead time) Gamma-Ray Bursts LAT suited to study the GeV tail of the GRB spectrum GBM will cover the range 10 keV-25 MeV and will provide a hard X-ray trigger for GRB GBM LAT GLAST: > spectral studies over full range to discriminate emission models (Synchroton, ICS) > Detection of  rays during brief intense pulses (~10  s dead time) GLAST will detect  200 GRB’s/yr with E >100 MeV

11. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 11 known gamma-ray pulsars LAT large effective area High photon statistics, detailed spectra  Discriminate between polar cap and outer gap emission models of  -ray production  -ray beams broader than their radio beams many radio quiet pulsars to be discovered Pulsar Physics with GLAST VELA Pulsar LAT high time resolution and detection efficiency Direct pulsation search in the  -ray band in all EGRET unidentifyed sources  Detect ~250 new gamma-ray pulsars

12. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 12 Systems work together to identify and measure the flux of cosmic gamma rays with energy 20 MeV - >300 GeV e+e+ e–e–  Calorimeter Tracker ACD [surrounds 4x4 array of TKR towers] Overview of LAT Precision Si-strip Tracker (TKR) - 18 XY tracking planes - Single-sided silicon strip detectors - (228  m pitch), 8.8 ·10 5 channels - Measure photon direction – Gamma ID Hodoscopic CsI Calorimeter (CAL) - Array of 1536 CsI(TI) crystals in 8 layers - 6.1 · 10 5 channels - Measure photon energy. Image the shower Anticoincidence Detector (ACD) - 89 plastic scintillator tiles surrounding towers - Reject background of charged cosmic rays - Segmentation removes self-veto effects at high energy Electronics and Flying Software DAQ Includes flexible and robust Hardware trigger and Software filters 4x4 modular array 3000 kg – 650 W Electronics and DAQ

13. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 13 16 “tower” modules, 37cm  37cm of active cross section 83m 2 of Si, 11500 SSD, ~ 1M channels 18 x,y planes per tower, 19 “tray” structures: - 12 with 3% X 0 on top (“Front”) - 4 with 18% X 0 on bottom (“Back”) – SuperGlast - 3 with no converter Every other tray is rotated by 90°, so each converter foil is immediately followed by an x,y plane of detectors Electronics on sides of trays: Minimize gap between towers 9 readout modules on each of 4 sides Electronics flex cables Carbon thermal panel One Tracker Tower Module  e+e+ e–e– particle tracking detectors conversion foil Anticoincidence shield Pair-Conversion Telescope calorimeter GLAST Tracker Design Overview GLAST LAT Tracker is the largest Si-tracker ever built for space applications

14. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 14 Gravity Probe B Launch on Delta II August 2004 Assembling of first tower completed July 2005 Completion of the LAT – Environmental testing December 2005 Delivery to Observatory Integration – Mate with Spacecraft and GBM and test February 2007 Kennedy Space Flight Center LAUNCH GLAST Master Schedule May 2007 Science operation begins!

15. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 15 E (MeV) resolve SNR sources distinguish shell emission from compact  -ray sources measure SNR spectra (  0 decay) SNR could be the source of CR nuclei interaction of accelerated nucleons with interstellar medium would produce  0 bump in the galactic spectrum (detected by EGRET) Cosmic-Ray production and acceleration in SNR A clear  0 decay signature from the shell would indicate SNR as a source of proton CR GLAST simulation showing SNR  -Cygni spatially and spectrally resolved from the compact inner gamma-ray pulsar GLAST 

16. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 16 2 Bismuth Germanate (BGO) Scintillation Detectors 12 Sodium Iodide (NaI) Scintillation Detectors LAT Major Purpose Provide low-energy spectral coverage (10 keV – 1 MeV) in the typical GRB energy regime over a wide FoV Provide rough burst triggers and locations Major Purpose Provide high-energy spectral coverage ( 150 keV – 25 MeV ) to overlap NaI at lower and LAT at high range The GBM Detector

17. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 17 - tray assembly started at the rate of 10/week - vibrational test - termo-vacuum test - thermal cycle SSD Procurement, Testing (Japan, Italy, SLAC) ­ 11500 flight SSD delivered (HPK) - full IV and CV tests at INFN - ~0.5% failure rate 342 Tray Assembly and Test (Italy) Status of Tracker construction SSD Ladder Assembly (Italy) - 1200 ladders completed (650 under construction) - 1000 electrical test (failure <~ 2%) 10pF ~2  m 1800pF C bulk ~2  mWafer cut 20V70VV dep 50nA100nAI leak  - 0.016% bad chans caused by bonding or probing - alignment precision of the order of few  m  First tower completed August 2004

18. ICHEP 04 - August 16-22, 2004, Beijing Monica Pepe – INFN Perugia 18 EGRET / LAT Properties EGRET LAT Energy range20 Mev – 30 GeV20 Mev – 300 GeV Energy resolution10 %9 % Effective Area1500 cm 2 10000 cm 2 Angular resolution 5.8 0 - 0.3 0 3.4 0 - 0.09 0 Field of View0.5 sr2.4 sr Flux sensitivity (E>100 MeV) 10 -7 cm -2 s -1 2 · 10 -9 cm -2 s -1 Dead Time 100 ms 10  s