GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 1 GLAST - an Astro-Particle Mission to Explore the High Energy Gamma Ray Sky Alessandro Brez INFN - sez. Pisa VERTEX 2003 Low Wood Lake Windermere, Cumbria, UK, September

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 2 SUMMARY The GLAST mission, the detector and the science goals The tracker of GLAST Status of the tracker construction and Engineering Model results

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 3 Profound Connection between Astrophysics & HEP The fundamental theory of Cosmic Genesis and the quest for experimental evidence has led to new and potential partnerships between Astrophysics and HEP. Some Areas of Collaboration:  Origin of cosmic rays  Dark Matter Searches  CMBR  Quantum gravity  Structure Formation  Early Universe Physics  Understanding the HE Universe Typical signatures  Ultra HE cosmic rays  gamma-rays -> GLAST   antimatter  extensive use of high resolution and reliable particle detectors now possible after long and successful experience in particle physics

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 4 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) Calorimeter (energy measurement) Particle tracking detectors Conversion foils Charged particle anticoincidence shield  e+e- Pair production is the dominant photon interaction above 10MeV: E  -> m e + c 2 + m e - c 2 GLAST  detection technique – pair conversion telescope

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 5 GLAST Instrument: 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.

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 6 LAT Instrument Performance Including all Background & Track Quality Cuts

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 7 The GLAST Participating Institutions American Team Institutions SU - Stanford University, Physics Department and EGRET group, Hanson Experimental Physics Laboratory SU-SLACStanford Linear Accelerator Center, SLAC, Particle Astrophysics group GSFC-NASA Goddard Space Flight Center, Laboratory for High Energy Astrophysics NRL - U. S. Naval Research Laboratory, E. O. Hulburt Center for Space Research, X-ray and gamma-ray branches UCSC- University of California at Santa Cruz, Physics Department SSU- Sonoma State University, Department of Physics & Astronomy UW- University of Washington, TAMUK- Texas A&M University-Kingsville Italian Team Institutions INFN - Instituto Nazionale di Fisica Nucleare: Units of Bari, Perugia, Pisa, Rome 2, Tries ASI - Italian Space Agency IFC/CNR- Istituto di Fisica, Cosmica, CNR Japanese Team Institutions University of Tokyo ICRR - Institute for Cosmic-Ray Research ISAS- Institute for Space and Astronautical Science Hiroshima University French Team Institutions CEA/DAPNIA Commissariat à l'Energie Atomique, Département d'Astrophysique, de physique des Particules, de physique Nucliaire et de l'Instrumentation Associée, CEA, Saclay IN2P3 Institut National de Physique Nucléaire et de Physique des Particules, IN2P3 IN2P3/LPNHE-X Laboratoire de Physique Nucléaire des Hautes Energies de l'École Polytechnique IN2P3/PCC Laboratoire de Physique Corpusculaire et Cosmologie, Collège de France IN2P3/CENBG Centre d'études nucléaires de Bordeaux Gradignan Swedish Team InstitutionsKTHRoyal Institute of Technology Stockholms Universitet

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa GeV 0.1 GeV 1 GeV 10 GeV 100 GeV 1 TeV Gamma Ray Bursts Unidentified sources Cosmic ray acceleration Active Galactic Nuclei Dark matter GLAST science - the sky above 100 MeV Pulsars Solar flares

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 9 Covering the Gamma-Ray Spectrum Broad spectral coverage is crucial for studying and understanding most astrophysical sources. GLAST and ground-based experiments cover complimentary energy ranges. The improved sensitivity of GLAST is necessary for matching the sensitivity of the next generation of ground- based detectors. GLAST goes a long ways toward filling in the energy gap between space-based and ground-based detectors—there will be overlap for the brighter sources. Predicted sensitivities to a point source. EGRET, GLAST, and Milagro: 1-yr survey. Cherenkov telescopes: 50 hours on source. (Weekes et al., 1996, with GLAST added)

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 10 Identifying Sources GLAST high resolution and sensitivity will Counting stats not included. Cygnus region (15 0 x 15 0 ), Eg > 1 GeV GLAST 95% C.L. radius on a 5  source, compared with a similar EGRET observation of 3EG /271 3 rd EGRET catalog still unidentified resolve gamma-ray point sources at arc-minute level detect typical signatures (e.g. spectra, flares, pulsation) for identification with known source types

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 11 Halo WIMP annihilations If SUSY uncovered at accelerators, GLAST may be able to determine its cosmological significance quickly. If true, there may well be observable halo annihilations q q  or Z  lines X X Good particle physics candidate for galactic halo dark matter is the LSP in R-parity conserving SUSY Example: X is  0 from Standard SUSY, annihilations to jets, producing an extra component of multi-GeV  flux that follows halo density (not isotropic) peaking at ~ 0.1 M   0 or lines at M  0. Background is galactic  ray diffuse. ~ ~ ~

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 12 Supersymmetric Cold Dark Matter searches with GLAST  lines 50 GeV 300 GeV Bergstrom et al. infinite energy resolution finite energy resolution 2-year scanning mode Total photon spectrum from galactic centre with  annihilation contribution

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 13 Gamma-Ray Bursts GLAST LAT will be best suited to studying the GeV tail of the gamma-ray burst spectrum. A separate instrument (GBM) on the spacecraft will cover the energy range 10 KeV – 25 MeV and will provide a hard X-ray trigger for GRB. GLAST should detect  200 GRB per year with E>100 MeV, with a third of them localized to better than 10, in real time. Excellent wide field monitor for GRB. Nearly real-time trigger for other wavelength bands, often with sufficient localization for optical follow-up. With a  10  s dead time, GLAST will see nearly all of the high-E photons. 1-  localization accuracy (arc min.) Simulated one-year GLAST scan, assuming a various spectral indexes. Energy dependent lags and the physics behind GRB temporal properties will be better studied by the broad energy coverage (10 KeV – 100 GeV) provided by GBM and LAT. GBM LAT

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 14 Gamma-Ray Bursts The origin of ultra-energy cosmic rays suggested to be GRBs (Waxman 1995) Burst of high energy  as signature of the evaporation of primordial black holes. transient signal, ~ 100 µs time scale light curves vs energy  fast response/ short dead time spectral studies for non-thermal emission model (synchrotron, ICS) fireball baryon fraction  high energy resolution Simulated time profile of a GRB detected by the LAT and the GBM. The pulses are narrower at LAT energies.

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 15 GLAST Tracker Design Overview Readout Cable Multi-Chip Electronics Module (MCM) 2 mm gap 19 Carbon-Fiber Tray Panels Titanium Flexure Mounts Carbon-Fiber Sidewalls (Aluminum covered) 16 “tower” modules, each with 37cm  37cm of active cross section 83m 2 of Si in all, like ATLAS SSD, ~ 1M channels 18 x,y planes per tower –19 “tray” structures 12 with 3% W on bottom (“Front”) 4 with 18% W on bottom (“Back”) – 3 with no converter foils –Every other tray is rotated by 90°, so each W 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

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 16 Tracker Production Overview Readout Cables UCSC, SLAC (Parlex) SSD Procurement, Testing SLAC,Japan, Italy (HPK) Electronics Fabrication, burn-in, & Test UCSC, SLAC (Teledyne) Tracker Module Assembly and Test Italy (Alenia Spazio) Tray Assembly and Test Italy (G&A) SSD Ladder Assembly Italy (G&A, Mipot) Composite Panel, Converters, and Bias Circuits Italy (Plyform): fabrication SLAC: CC, bias circuits, thick W, Al cores , Module Structure Components SLAC: Ti parts, thermal straps, fasteners. Italy (Plyform): Sidewalls 342

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 17 SSD Electrical Test Rate SSD in Italy9452 (82% of total, enough for 16 towers) SSD tested7373 (64% of total) SSD to review201 SSD rejected44 Cumulative test rate

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 18 SSD Electrical Properties Specification: leakage current <500 nA at 25  C and 150 V

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 19 Ladder Assembly Manual fast AND precise method 24 ladder assembly tools used in parallel Very good ladder alignment obtained Encapsulated bondings Ladder assembly tool

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 20 Ladders Electrical Tests Electrical test results: 1.Ladder tested513 2.Accepted501(98%) 3.Broken edge 6 4.High current 6 (>2  The cause of problem 3 has been corrected.

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 21 Ladders Electrical Tests Depletion voltage Leakage current at 150 V

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 22 Tray Panel Fabrication Machining of the Carbon-Carbon closeout material is just starting. Face sheets, cores, inserts, and tungsten are in hand. Bias circuits are out for quote. PRR actions are being closed. Gr/CE Face Sheet C-C MCM Closeout Wall Thermal Boss 1 lb/ft 3 Aluminum Honeycomb Core C-C Structural Closeout Wall

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 23 Tracker Tray with Payload The tray “payload” is bonded to the sandwich structure using epoxy, with the exception of the SSD bonding, which is done with silicone. –Silicone decouples the thermal/mechanical effects from the tray Tray TypeHoneycomb Core Face sheet Plies W Converter MID1 lb/ft 3 43% Xo LIGHT1 lb/ft 3 4NO HEAVY3 lb/ft 3 618% Xo TOP1 lb/ft 3 43% Xo BOTTOM3 lb/ft 3 6NO

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 24 E.M. Results: DIMENSIONS

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 25 Vibrational test Sine sweep before/after randomRandom vibration + White noise Resonance search: 0 = 815 Hz, Q  51 Resonance check: 0 = 809 Hz, Q  49 Z accelerometer response X accelerometer response Y accelerometer response All the EM trays have been successfully tested at qualification level. No damages or relevant frequency shifts have been observed TG07

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 26 Bare Panel: N.D.I. Test Honeycomb – Skin debonding ESPI: Thermal Loads very effective to detect bare panel defects Honeycomb crash Skin-closeout debonding

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 27 TG07: Bare Panel + W + Bias Plane ESPI: Vibration TEST 817Hz first resonance mode 1860Hz second resonance mode

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 28 Assembly phases Tray positioning Ladder positioning Microbonding Ladder assembly on the trays

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 29 Ladder alignment results  =46  m  =32  m  =28  m x y measurement points 0.2mm MCM side

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 30 Tray box Connector saver Fixation points Handle N2 inlet The tray box allows safe shipping and storage. Through the connector savers the tray can be fully tested in the closed box.

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 31 Qualification-like test: temperature range: -30°C  +50°C T 0 = 24°C number of cycles: °C, +50 °C (dT/dt) = 0.5 °C/min Temperature (°C)  L/L (m  )  T=25 °C:  L/L  100   T=-55 °C:  L/L   Trays Thermal qualification cycles Thermal test lot ≥ 4 trays/cycle in 4 climatic chambers (2 ready by Pg in Terni, 1 foreseen in Pi, 1 foreseen in Ba) Test rate/climatic chamber ∼ 1 tower/month

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 32 Assembly of EM Tower in G&A Trays alignment on assembly jig Geometrical tolerances well within limits (0.3 mm). Cabling

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 33 Mini-Tower Assembly & Test (Aluminum grid fixture is removed) Mini-tower concept: 3 XY working planes for detection capability test

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 34 Cosmic Rays – Online DATA The trigger occurs when particles traverse the 6 consecutive layers of the MiniTower.

Detection efficiency 60% 1MIP Full efficiency plateau up to  ½ MIP beginning of efficiency plateau is already as low as 10 –7 (mainly cosmics) DAC Threshold = 10

layer Exp STDEV (um)Meas STDEV (um)Meas AVG (um) X X X Y Y Y RatioExpected valueMeasured value mean(X2)/mean(X1)0.46 mean(X2)/mean(X3) mean(Y2)/mean(Y1) mean(Y2)/mean(Y3) Alignment Spatial resolution

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 37 Integration of MiniTKR and CAL at SLAC Courtesy of I&T team

GLASTGLAST Vertex 2003 September 15-19, 2003 Alessandro Brez – INFN Pisa 38 conclusions GLAST construction is going on with very good results. The close combined effort of HEP Institutes with high tech companies lead to a fast, precise, high yield production. The HEP Institutes have defined the project and will conduct the test activity. The industrial counterpart is essential in defining the more technological details, provides the specialized manpower, assure the Quality certification of the production.