1. WP-Technology Working Group Future of Ground Based Gamma-ray Astronomy Feb 8, 2007 1 Technology & Cost WP Working Group GOALS With the Current Generation of IACTs, Ground-based gamma-ray astronomy has entered a new era! Technology detector R&D: –Identify technology and collaborate in the detector R&D required to design a future ground based gamma-ray observatory Simulations: –To perform simulations needed to test different designs for science goals and cost/sensitivity Who we are: Jim Buckley, Karen Byrum, Brenda Dingus, Gary Drake, Steve Fegan, John Finley, Liz Hays, Jamie Holder, Deirdre Horan, Alexander Konopelko, Frank Krennrich, Stephen Lebohec, Andy Smith, Vladimir Vassiliev, Scott Wakely PLEASE JOIN THE FUN

2. WP-Technology Working Group Future of Ground Based Gamma-ray Astronomy Feb 8, 2007 2 Gamma ray ( or Cosmic ray) interacts in the upper atmosphere (big calorimeter) and initiates a shower of charged particles (mainly e +/- ) The shower develops along the direction of the primary gamma. High energy electrons with v> c/n emit Cherenkov light. Cherenkov Light Flashes (~ a few ns) are briefly brighter than fluctuations in night sky light. IACTs (Imaging Atmospheric Cherenkov Telescopes) record this Cherenkov flash. EAS detectors look for the particles directly. About 25% of primary gamma ray energy makes it to the ground in the form of particles. Background is cosmic ray showers -isotropic Extensive Air Showers

3. WP-Technology Working Group Future of Ground Based Gamma-ray Astronomy Feb 8, 2007 3 Ground Based vs Satellite Differences  Satellite (Glast 30MeV – 300GeV):  Primary detection  Small effective area ~1m 2  lower sensitivity  Large angular opening  Large duty-cycle  Large cost  Lower energy  Low bkg  IACT (100GeV – 1TeV) / EAS (500GeV – 100TeV):  Secondary detection (Cherenkov/ Tail catcher)  Large effective area ~10 4 m 2 /Moderate-Large  higher sensitivity  Small/ Large angular opening  Small/ Large duty-cycle  Low cost  High energy  High bkg

4. WP-Technology Working Group Future of Ground Based Gamma-ray Astronomy Feb 8, 2007 4 Technology WP Working Group Goals for The Next Ground Based Generation: Needs lower energy threshold. Present generation at ~100GeV -> can this be made 10GeV? –higher source count rate –more cosmological reach Needs higher intrinsic source sensitivity, down to 10 -12 ergs/cm 2 s in a few hours (x10-100 present arrays) –discover more objects –see more distant objects Needs wider field of view –survey the sky –find diffuse emissions Higher duty factor –Serendipitous discovery –All sky monitor Robotics/Lightweight mirrors Altitude, bigger dishes, higher QE, high speed trigger, ASICs, FPGAs Higher QE, triggering, better bkgd rejection, smaller pixels Hybrids, new optical designs Bkgd rejection, triggering

5. WP-Technology Working Group Future of Ground Based Gamma-ray Astronomy Feb 8, 2007 5 http://future-tev.uchicago.edu/