AGIS Advanced Gamma-ray Imaging System Jim Buckley (for the AGIS - - PowerPoint PPT Presentation

AGIS

Advanced Gamma-ray Imaging System Jim Buckley (for the AGIS R&D group) Washington University Toward the Future of Very High Energy Gamma-Ray Astronomy SLAC, November 8, 2007

“Towards the Future” Meetings

“Ground-based Gamma-ray Astronomy: Towards the Future”, Oct. 20-21, 2005, Malibu, CA (UCLA) “Ground-based Gamma-ray Astronomy: Towards the Future”, May 11-12, 2006, Santa Fe, NM (LANL) Satellite meeting at GLAST Symposium, Feb 8, 2007, Palo Alto, CA “Future of Very High Energy Gamma-Ray Astronomy”, May 13-14, 2007, Chicago, IL (U. Chicago) - Formation of AGIS R&D group

Future Gamma-Ray Observatories APS White Paper Meeting

• Thurs. 8 Feb 2007 in McGaw Hall 1:30-5:00

Bring a 1-viewgraph idea to share or just come and listen. Everyone is welcome and encouraged to participate now or in the future. Organizing Committee: Brenda Dingus, Henric Krawczynski, Martin Pohl, Vladimir Vassiliev Additional Members of Editorial Board: Francis Halzen, Werner Hofmann, Steve Ritz, Trevor Weekes 8 Feb 2007 AGENDA: 1:30-1:45 Motivation & Organization 1:45-2:10 Extragalactic Working Group 2:10-2:35 Gamma Ray Burst Working Group 2:35-3:00 Dark Matter Working Group 3:00-3:15 Break 3:15-3:40 Galactic Compact Sources Working Group 3:40-4:05 Galactic Diffuse Working Group 4:05-4:30 Technology Working Group 4:30-5:00 General Discussion

U.S. Gamma-ray Community

VERITAS MILAGRO GLAST

Status of VHE Astronomy

~58 credible sources ~11 PWN ~16 AGN (15 blazars+M87) ~9 Shell-type SNR 4 X-ray binaries (HMXB, microquasars, Be-binaries) 18 unidentified sources

1ES1101-232 Mkn421 Mkn180 1ES1218+304 M87 H1426+428 PG1553+113 Mkn501 SgrA* 1ES1959+650 PKS2005-489 PKS2155-304 BL-Lac 1ES2344+514 H2356-309 1ES0229+20 1ES0347-121

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Science Drivers - White Paper

Science case for the future ground-based gamma-ray experiment is being developed by the APS whitepaper working group (earlier talk by Krawczynski)

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The charge from APS Editorial board Organizational meetings Meeting at the GLAST Symposium

WORKING GROUPS

Extragalactic Astrophysics Galactic compact objects SNR and cosmic rays Dark matter Gamma-ray bursts Technology

The future of ground-based gamma-ray astronomy

APS White Paper

The Status and Future of Ground Based Gamma- Ray Astronomy In the last two years ground-based gamma-ray

• bservatories have made a number of stunning

astrophysical discoveries which have attracted the attention of the wider scientific community. The high discovery rate is expected to increase during the forthcoming years, as the VERITAS observatory and the upgraded MAGIC and HESS observatories commence scientific observations and the space- based gamma-ray telescope, GLAST, is launched. The continuation of these achievements into the next decade will require a new generation of ground-based observatories. In view of the long lead time for developing and installing new instruments, the Division of Astrophysics of the American Physical Society has requested the preparation of a White Paper on the status and future of ground-based gamma-ray astronomy. Scientists from the entire spectrum of astrophysics are invited to contribute to the concepts and ideas presented in the White Paper. We wish to stress that international participation is encouraged.

The charge from APS Editorial board Organizational meetings Meeting at the GLAST Symposium

Scientific Drivers

Wide Field

• f View

Effective Area Energy Resolution Energy Threshold Angular Resolution Slew Speed Instantaneous Sensitivity Integrated Sensitivity PWN ✔ ✔ ✔ ✔ ✔✔ ✔✔ SNR ✔✔ ✔ ✔ ✔✔ ✔✔ Pulsars ✔ ✔ ✔✔ ✔✔ XRBs ✔ ✔ ✔ ✔ ✔✔ ✔✔ UIDs ✔✔ ✔ ✔ ✔ ✔✔ ✔ ✔✔ AGN ✔✔ ✔ ✔ ✔ ✔✔ GRBs ✔✔ ✔✔ ✔ ✔✔ ✔✔ ✔✔ Dark Matter ✔✔ ✔ ✔✔ ✔✔ ✔ ✔✔ Galactic Diffuse ✔✔ ✔ ✔ ✔✔ Galaxy Clusters ✔ ✔ ✔ ✔ ✔✔ Galaxies ✔ ✔ ✔✔ ✔✔ IACTs

☺☺ ☺ ☺ ☺☺ ☺ ☺☺ ☺

EAS Detectors

☺☺ ☺

n/a

☺☺

Space Telescopes

☺☺ ☺☺ ☺☺ ☺

n/a

☺☺

(JB version of the “Krennrich Science Matrix”)

Time-resolved Spectra

Instantaneous point source sensitivity and energy resolution is of critical importance for studying AGN and GRB emission. Imaging atmospheric Cherenkov instruments are unmatched for such studies. Box shock acceleration with losses from escape, IC and synchrotron cooling,

• E. Schlafly (Stanford) and JB (left: electron spectrum, right: radiation spectrum)

AGIS Design Goal

Differential flux sensitivity of an ideal km2 telescope array sensitivity curve (courtesy S. Fegan)

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Note on Differential Sensitivity

Toy model calculation of number of particles reaching ground level as an energy estimator for showers at zenith, impact in center of EAS detector (courtesy Slava Bugaev). Difficult to compare EAS detectors for differential flux sensitivity since first spectral measurement is typically well above the quoted threshold

104 103 102 104 103 102 10 1 10-1 Energy, E (GeV) Number of particles log file; S=inf; e+- particle output; S=104 m; e+-

(from Bernloehr, S. Funk Thesis)

Future of Ground-based Gamma-Ray Astronomy

GLAST is coming! Even though GLAST will enjoy operation in vacuum, the ground-based community can not make judgements about the future of ground-based gamma-ray astronomy in a vacuum! Sensitivity estimate for future ACT and future space-based instrument using the largest launch vehicle fairing - cross-over moves down from 100 GeV to 30 GeV

Angular Resolution

(VERITAS angular resolution from Krawczynski et al. (2005), future ground-array from Bugaev et al. (2007), Ideal ground-array from W. Hofmann (2005?), Kinetic limit from

• S. Hunter.

Instrument budget $100M Target energy threshold <40 GeV Effective area 0.7-3 km2 Number of telescopes 25-100 Effective mirror area (diameter) 40m2 (7m)

• 250m2(18m)

Telescope spacing unform (graded) array 80-160m (20m-200m) Sensitivity at 200 GeV 10-13 erg cm2 s-1 Telescope FOV diameter 6, 8° Number of pixels per camera 5,000-10,000 Pixel diameter 0.15°-0.05° Camera+electronics cost per channel $50-$400 Mechanical+optics cost per telescope $0.5M-$2.0M

AGIS Specifications

Instrument budget $100M Target energy threshold <40 GeV Effective area 0.7-3 km2 Number of telescopes 25-100 Effective mirror area (diameter) 40m2 (7m)

• 250m2(18m)

Telescope spacing unform (graded) array 80-160m (20m-200m) Sensitivity at 200 GeV 10-13 erg cm2 s-1 Telescope FOV diameter 6, 8° Number of pixels per camera 5,000-10,000 Pixel diameter 0.15°-0.05° Camera+electronics cost per channel $50-$400 Mechanical+optics cost per telescope $0.5M-$2.0M Small/dense/high-res Large/sparse/low-res Both approaches Technological challenges come with pushing the angular resolution and field of view, requiring a new optical design and very low cost photodetectors and electronics The AGIS R&D proposal will address the most challenging corners of this specification phase space.

AGIS R&D Proposal

Adler Planetarium Lucy Fortson, Daniel Steele Argonne National Lab K.Byrum, G. Drake, V. Guarino, D. Horan, R. Wagner Barnard/Columbia Reshmi Mukherjee U.C. Santa Cruz David Williams, Michael Schneider University of Chicago Simon Swordy, Scott Wakely University of Delaware Jamie Holder Harvard-Smithsonian CfA Trevor Weekes University of Iowa Phil Kaaret Iowa State University Frank Krennrich McGill University David Hanna Penn State Abe Falcone Stanford U./SLAC Stefan Funk, Roger Romani, Hiro Tajima UCLA Stephen Fegan, Rene Ong, Vladimir Vassiliev

• U. Utah

Stephan LeBohec, David Kieda Washington University

• J. Buckley, Y. Bugaev, P. Dowkontt, H. Krawczynski

International advisors/participants: German Herman, Razmik Mirzoyan NSF Proposal: (Swordy, PI) $1M/yr, 3 years; DOE Proposal: (Byrum, PI) $1M/yr, 3 yrs

AGIS Work Plan

Simulation studies of optimum array parameters Trade studies of different mechanical/optical designs Detailed design and construction of 2-mirror (Schwarschild-Coulder) prototype telescope Investigation of mirror fabrication techniques + metrology of optics and development of active alignment system Parallel developments of low-cost camera electronics and trigger electronics Evaluation of different photodetectors and light concentrator designs Development of a design concept for a low-cost, fast-slewing alt-az mount Demonstration of vertical integration of the modular camera through construction of two small-FOV camera modules

Management Plan

Coordinators for major activities: Project Coordinator: James Buckley (Wash. U.) Photodetectors: Robert Wagner (ANL) Electronics: Paul Dowkontt (Wash. U.) Telescope and Mirrors: Vladimir Vassiliev (UCLA) Telescope Mechanical: Victor Guarino (ANL) Conduct parallel design studies Preliminary design review will result in down- selection for prototype construction Final design reviews (with external reviewers) will result in recommendations for the technology roadmap for AGIS

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Simulation Studies

Dense-packed array can achieve a lower threshold (Cell Effect, Vassiliev and Fegan) Uniform array with relatively large spacing may provide best area/telescope (Bugaev talk, tomorrow) A dense array may provide better angular resolution (Hofmann) and may serve a dual use, e.g. multiple arrays pointed at different sources for wider FOV (ELFF concept Either Large-FOV or Full-array - Krawczynski and JB)

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Energy [GeV] Effective collecting area per cell [m2] 80m 91m 106m 128m 160m 213m

(from S. Fegan and V. Vassiliev, AGIS proposal) (from H. Krawczynski, AGIS proposal)

Optical Design

We will build prototype telescope based on Schwarzschild-Coulder optical design (Vassiliev, Fegan and Brousseau, 2007,

• Astropart. Phys., 28, 10-27).

9m diameter primary Camera framework for testing modules Low-cost, fast alt-az mount SC design has excellent angular resolution, fast

• ptics with a very small plate scale (f/0.6),

allowing low cost/pixel MAPMTs However, large secondary obscuration, highly

• blique light rays at the camera, tight

tolerances and aspheric optics - R&D is needed before we can proceed with large-scale production. Will also conduct cost trade studies for other approaches (e.g., large f/# Davies-Cotton design) Camera

Modular Camera

2.8° x 2.8° subfield with 1600 0.07° pixels (~ Whipple FoV). Each subfield has a monolithic backplane and integral pattern trigger, HV control, Gbps outputs to DACQ system. One 64 channel module, shown with 2” MAPMT (4 16 channel MAPMTs are baseline

• ption). Front end electronics, and possibly

ADCs are located on boards. Flex circuits allow adjustment for a curved focal plane. Ultrabialkali MAPMTs and SiPMs will also be considered.

Pixel Size / Angular Resolution

The optimum pixel size is still to be determined. Simulation of 200 GeV gamma (using GrISU) with f/3 DC telescope, 8000 pixels, no noise, Eventdisplay analysis Potential increase in angular resolution (if not SNR) for high resolution camera (Bugaev et al., 2007) could have important science return. Alternative approach of dense- packed array of telescopes should be evaluated. More detailed simulation studies are required to determine the

• ptimum pixel size and field of

view. (Simulation by C. Weaver, WU)

Camera Testbed

Prototype camera modules and trigger electronics will be tested on two 3.5m telescope array (TA) scopes. Since the scopes have a similar plate- scale to the 9m-SC prototype we will get similar angular resolution (0.1deg pixels) 2 TA scopes will be operated at the Utah Test Observatory (40 38.8’N, 112 31.5W) near Grantsville at 1.3km. Kieda and LeBohec (U. Utah) will manage the site.

Trigger Electronics

Trigger electronics will include pattern triggers with position information

• f triggering pixels sent over high-speed fiber-optic link, real time parallax

correcton (parallel development efforts are ongoing at Wash. U and ISU/ ANL)

(Prototype trigger board with Paroli style fiber-optic transcievers developed at

• Wash. U. by Buckley, Bose and Tyson). Working 500 channel pattern trigger, and

fiber-optic interface have been fully tested.

MUX/FADC approach

• Wash. U. will develop multiplexed FADC approach. With 10:1 multiplexing, cost per

channel is estimated to be $25 (for 10:1 multiplexing) to $50 (for 4:1 multiplexing) including both the ADC and full DACQ system. Cost and power are high compared with ASICs, but pipelined FPGA processing adds numerous digital signal processing capabilities for triggering and data compression.

Pixel #n RAM FADC Main Pattern Trig (L2) Array (L3) L2 triggers from

• ther Telescopes

FADC chans. from other Pattern Delay Delay stop Digital CFD 400 FADCs for 1600 MAPMTs Subfield 3 Subfield 4 Subfield 1 Subfield 2 MAPMT Camera Trig ! DAC DAC Trig Subfield 1 Subfield 4 Pixel #n CFD outputs Trig. 400 Chan. Pattern FPGA buffer

Switched Cap. Array

Hiro Tajima (SLAC) working with Gary Varner (Hawaii) will develop an ASIC approach incorporating a 16-channel SCA device with 4k-memory depth and built in ADCs based on the LABRADOR ASIC Swordy and Wakely (U. Chicago) will develop an approach based on existing DRS (Domino Ring Sampler) ASICs manufacured by PSI, unsing an external 50Msps FADC readout.

Write Pointer Read Pointer Outputs from

• ther Channels

L2 Triggers from

• ther

Telescopes stop ADCs Camera Subfield Pattern Trigger (L2) Timing and Read/Write Control Switched Capacitor Array Discriminator Discriminator Preamp Photodetector Signal Array Trigger (L3)

BLAB1 ASIC will be the basis of the new 16-cahnnel design (courtesy G. Varner)

Summary

Very good work on building the science case is underway through the whitepaper group and meetings like this. For AGIS, the first major R&D proposal has been submitted and a core technical group has been formed. Very good contributions have been made by a large number of people, we are on a positive trajectory towards resolving most of the technology challenges. We welcome new members of AGIS - it is still very early, and a good time to joint the collaboration. We need to begin a serious international site survey effort in parallel with the technology R&D proposal - this should be coordinated with work by the CTA group. We will continue to maintain a very close working relationship with the CTA group and Japanese groups, and will openly exchange ideas, perhaps working towards a true international collaboration.