GLAST:Gamma Ray Large Area Telescope GLAST-Italia: Partecipation to the LAT and construction commitments R.Bellazzini Italian Project Manager 1 Milano - 16/03/01

Pair-Conversion Telescope Photons materialize into matter-antimatter pairs: E -> me+c2 + me-c2  e+ e- Calorimeter (energy measurement) Particle tracking detectors Conversion foils Charged particle anticoincidence shield GLAST Concept Low profile for wide f.o.v. Segmented anti-shield to minimize self-veto at high E. Finely segment calorimeter for enhanced background rejection and shower leakage correction. High-efficiency, precise track detectors located close to the conversions foils to minimize multiple-scattering errors. Modular, redundant design. No consumables. Low power consumption (580 W) 2 Milano - 16/03/01

The Large Area Telescope (LAT) DAQ Electronics Grid Tracker Calorimeter ACD Thermal Blanket Array of 16 identical “Tower” Modules, each with a tracker (Si strips) and a calorimeter (CsI with PIN diode readout) and DAQ module. Surrounded by finely segmented ACD (plastic scintillator with PMT readout). Aluminum strong-back “Grid,” with heat pipes for transport of heat to the instrument sides. 3 Milano - 16/03/01

The LAT Hardware 4 Milano - 16/03/01

GLAST Tracker Design Overview 16 “tower” modules, each with 37cm  37cm of active cross section 83m2 of Si in all, like ATLAS 11500 SSD, ~ 1M channels 18 x,y planes per tower 19 “tray” structures 12 with 3% Pb or W on bottom (“Front”) 4 with 18% Pb or W on bottom (“Back”) 2 with no converter foils Every other tray is rotated by 90°, so each Pb foil is followed immediately by an x,y plane of detectors 2mm gap between x and y oriented detectors Trays stack and align at their corners The bottom tray has a flange to mount on the grid. 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 5 Milano - 16/03/01

Tray assembling Carbon-carbon closeout Trays are C-composite panels (Al hexcel core) Carbon-fiber walls provide stiffness and the thermal pathway from electronics to the grid. 6 Milano - 16/03/01

Prototyping of the GLAST SSD Preserie HPK detector on 6’’ wafer Gained experience with a large number of SSD (~5% of GLAST needs) Additional Prototypes: Micron (UK), STM (Italy), CSEM (Switzerland) 7 Milano - 16/03/01

Project schedule Calendar Years Formulation Implementation SRR NAR 2000 2001 2002 2003 2004 2005 2010 Formulation Implementation SRR NAR M-PDR M-CDR I-PDR I-CDR Inst. Delivery Launch Build & Test Engineering Models Flight Units Inst. I&T Schedule Reserve Inst.-S/C Ops. Calendar Years SSD Procurement Ladder Production Tray Assembly 8 Milano - 16/03/01

INFN Collaboration Sezioni INFN Bari Perugia Pisa Roma 2 Trieste Udine 30 FTE physicists Collaborations Dipartimento di Ingegneria Aerospaziale (Univ. Pisa) Dipartimento di Ingegneria dei Materiali (Univ. Perugia) 9 Milano - 16/03/01

Construction money ceiling (INFN+ASI) of 20 GL Status of INFN approval process Construction money ceiling (INFN+ASI) of 20 GL ˜ 9.5 M$ INFN is willing to approve 10 Milano - 16/03/01

GLAST: MoA …... and ASI and ASI …... 11 Milano - 16/03/01

Construction commitment and ASI 12 Milano - 16/03/01

Construction commitment and ASI 13 Milano - 16/03/01

Construction commitment 14 Milano - 16/03/01

Construction commitment 15 Milano - 16/03/01

Construction commitment 16 Milano - 16/03/01

Mechanics: on-going activities Ladders: Design and production of jiigs and tools for ladders assembly Definition of alignment and glueing procedure of ladders on trays Ladders prototyping in collaboration with industries (G&A, MIPOT, LABEN) Trays: Super-GLAST payload definition and prototyping (PLYFORM) Definition of trays acceptance mechanical tests Construction of 4 trays fully equipped with final sensors and electronics Towers: Construction of a tower Engineering Model (19 trays) for qualification of procedures and industrial partners 17 Milano - 16/03/01

Sensors: on-going activities Qualification of sensor Suppliers: Complete set of measurements on pre-serie prototypes from various suppliers ( HPK-Japan, Micron-UK, ST-Italy ): inter-strip capacitance, bulk capacitance, depletion voltage, dark current, decoupling capacitance and resistance, ... Definition of automatic test procedures for mass production 18 Milano - 16/03/01

Tests on preserie of final HPK SSD Comparison between HPK and GLAST results Measurements at Hiroshima U. (20), INFN-Pisa (10), SLAC (5) 19 Milano - 16/03/01

Tests on preserie of final HPK SSD Mechanics and dimension measurements Average tilt Planarity Thickness Strip size = 64 ± 1 mm Pitch = 228.01 ± 0.01 mm Active width = 87557 ± 5 mm 20 Milano - 16/03/01

Software: on-going activities Simulation - development in G4 of the GLAST-LAT - XML description of LAT geometry - digitization (charge sharing, FE simulation, TOT) - MC validation Track reconstruction - study of TOT to improve vertexing - angular accuracy study - energy measurement from angular dispersion - development of a reduced version of reconstruction package lab-tests of stack of trays or a tower with cosmic rays Interactive event display (evaluating WIRED2) 21 Milano - 16/03/01

XML C++ generic model We have done the C++ hierarchy of classes for accessing the XML geometry description of GLAST 22 Milano - 16/03/01

Gamma Ray Telescope G4 example Official advanced example in release 3.0 of G4... 23 Milano - 16/03/01

Conclusions Activity of GLAST-Italy started full steam on both hardware and software The Italian Collaboration is providing critical contributions to the LAT design and to the preparation for construction Strong need of fast signature of MoA between STANFORD /SLAC and ASI/INFN Strong need of formal approval from INFN and ASI of the spending profile to start soon tenders for SSD procurement on tracker construction 24 Milano - 16/03/01