1. miniHAWC Jordan Goodman Beijing – June 2006 Jordan Goodman University of Maryland mini- High Altitude Water Cherenkov experiment  miniHAWC

2. Jordan Goodman Beijing – June 2006 Lexicon Milagro – Existing water Cherenkov wide-field all-sky gamma-ray observatory near Los Alamos, NM. HAWC – A ambitious effort to construct an wide-field all-sky observatory with point source sensitivity of the Whipple 10m. miniHAWC – Demonstrate HAWC technology at low cost with Milagro PMTs and instrumentation, with potentially large scientific payoff.

3. miniHAWC Jordan Goodman Beijing – June 2006 Detector Layout Milagro: 450 PMT (25x18) shallow (1.4m) layer 273 PMT (19x13) deep (5.5m) layer 175 PMT outriggers Instrumented Area: ~40,000m 2 PMT spacing: 2.8m Shallow Area:3500m 2 Deep Area:2200m 2 HAWC: 5625 or 11250 PMTs (75x75x(1 or 2)) Single layer at 4m depth or 2 layers at Milagro depths Instrumented Area: 90,000m 2 PMT spacing: 4.0m Shallow Area:90,000m 2 Deep Area:90,000m 2 miniHAWC: 841 PMTs (29x29) 5.0m spacing Single layer with 4m depth Instrumented Area: 22,500m 2 PMT spacing: 5.0m Shallow Area:22,500m 2 Deep Area:22,500m 2

4. miniHAWC Jordan Goodman Beijing – June 2006 4300m 2600m Difference between 2600m (Milagro) and 4300m (Tibet): ~ 6x number of particles ~ 2x lower energy threshold Altitude

5. miniHAWC Jordan Goodman Beijing – June 2006 Detector Layout Milagro: 2 layers at depths 1.5m – “Air Shower” Layer 5.5m – “Muon” Layer miniHAWC: Single intermediate layer opaque curtains between cells 4m 5.5 m 5 m 2.8 m 1.5 m

6. miniHAWC Jordan Goodman Beijing – June 2006 Curtains A high altitude version of Milagro would trigger at >10kHz. Need to control spurious triggers due to single muons. Install curtains to optically isolate the PMTs. Intrinsic Gamma hadron separation

7. miniHAWC Jordan Goodman Beijing – June 2006 Milagro Instrumentation 899 8” Hamamatsu PMTs –Bases, encapsulation Single rg59 cable for data and HV. Custom front end boards –Signal shaping and threshold detection –Trigger primitive generation –Pulse height through TOT method. FastBus TDC’s –Capable of ~2000Hz or 6MB/s readout VME-FastBus interface for readout

8. miniHAWC Jordan Goodman Beijing – June 2006 Gamma/Hadron Separation Lateral distribution of EM energy and muons.

9. miniHAWC Jordan Goodman Beijing – June 2006 Simulation Strategy Use Milagro Simulation/Reconstruction software (without weighting). Use observed Milagro crab signal to anchor simulations to reality.  Shared systematics with Milagro. Use new  /hadron discrimination variable for HAWC/miniHAWC that excludes the core location. C Milagro = (nPMTs > 2 PE)/(Max “muon layer” hit) C miniHAWC =(nPMTs > 2 PE)/(Max “muon layer” hit >20m from core)

10. miniHAWC Jordan Goodman Beijing – June 2006 Triggering with Curtains Multiplicity trigger at ~70 PMTs gives same trigger rate as Milagro at 50 PMTs Much higher Gamma area. protons gammas

11. miniHAWC Jordan Goodman Beijing – June 2006 Energy (Crab Spectrum, nTop/cxPE>5.0.,  <30 O ) Significance from Crab Transit (~5 hr) 4  Crab signif/year 80  5  point source sensitivity reach ~60mCrab of 1 year survey Energy Resolution ~30% above median Angular Resolution 0.25 O -0.40 O S/B (hard cuts) ~ 1:1 for Crab Typical day 20 excess on 25 bkg miniHAWC Sensitivity Q (sig/√bg) ( miniHAWC/Milagro) = 15 Single layer doesn't limit sensitivity nTrig>50 Ethr~700 GeV nTrig>200 Ethr~2TeV

12. miniHAWC Jordan Goodman Beijing – June 2006  = ~0.4 o  = ~0.25 o Angular Resolution n Trigger = 50 n Trigger = 200

13. miniHAWC Jordan Goodman Beijing – June 2006  / hadron Separation Cut: nTop/cxPE>5.0 Eff  = 34% Eff CR= 3% Cut: nTop/cxPE>5.0 Eff  = 56% Eff CR= 1.5%   = 56% -> 28%  CR = 3% -> 0.4% (shape only) Hess Q Factor (sig/√bg) Cuts soft hard miniHawc 2 4.5 Hess 3.2 4.4

14. miniHAWC Jordan Goodman Beijing – June 2006 Gamma/Hadron Separation Gammas Protons 30 GeV70 GeV230 GeV 20 GeV70 GeV 270 GeV Size of miniHAWC Size of Milagro deep layer

15. miniHAWC Jordan Goodman Beijing – June 2006 Effective Area Gamma Area:  5.0  <1.0 O 200 PMT Trigger 80 PMT Trigger 20 PMT Trigger Pond Area

16. miniHAWC Jordan Goodman Beijing – June 2006 Comparison of Effective Areas 50 Tube Trigger

17. miniHAWC Jordan Goodman Beijing – June 2006 Sensitivity Increase from Milagro to MiniHawc 15x Sensitivity increase over Milagro ~3x from Altitude, Area ~3x from  /hadron separation ~1.5x from Angular resolution ~60mCrab sensitivity (5  in 1year)

18. miniHAWC Jordan Goodman Beijing – June 2006 Point Source – Weighting (in Milagro) Hard Cuts: NFIT>=200,C>6.0 Std Cuts: NFIT>=20,C>2.5 Excess = 60, Off = 140, S:B = 1:2.3  hadron background =~ 1x10 -5 Excess = 5410, Off = 1218288, S:B = 1:225  hadron background =~ 0.1 No weighting applied to estimates of miniHAWC sensitivity. Large improvements in sensitivity likely.

19. miniHAWC Jordan Goodman Beijing – June 2006 GRB Sensitivity Fluence Sensitivity to 100s GRB. Both Milagro and miniHAWC can “self trigger” and generate alerts in real time. GRB rate in FOV ~100 GRB/year (BATSE rate) Milagro miniHAWC

20. Jordan Goodman Beijing – June 2006 The Diffuse Galactic Plane in miniHAWC and HAWC Use Neutral H map to trace out VHE Gamma-Ray flux. Normalize to Milagro observed TeV diffuse emission from the Galactic plane.

21. miniHAWC Jordan Goodman Beijing – June 2006 Pond Design Fiducial volume: 150m x 150m x 4m Actual size: 170m x 170m x 5m 1:1 slope at perimeter Min 4½m depth to allow for 4m over PMTs. Total volume: 115 Ml 170m 150m 4.5-5.0 m 6m

22. miniHAWC Jordan Goodman Beijing – June 2006 Building Construction Prefabricated steel building –Components manufactured at factory. –Shipped to site (~9 trucks) –Beams bolted not welded. –Cost ~1M$ (not installed) Building installation ~400 k$ Pond excavation ~300 k$ Liner cost ~600 k$ Total facility cost ~2.5-3.0M$ 170m

23. miniHAWC Jordan Goodman Beijing – June 2006 Sierra Negra, Mexico ~1 ½ hr drive from Puebla ~4hr drive from Mexico City Saddle between Sierra Negra (z=4500m) and Orizaba (z=5600m) Site under development as a multiuse scientific facility.

24. miniHAWC Jordan Goodman Beijing – June 2006 Sierra Negra, Mexico Elevation = 4030m Latitude = 19 O 00’N Longitude = 97 O 17’ W

25. miniHAWC Jordan Goodman Beijing – June 2006 Sierra Negra, Mexico Elevation = 4030m Latitude = 19 O 00’N Longitude = 97 O 17’ Wc LMT – 50m dish

26. miniHAWC Jordan Goodman Beijing – June 2006 La Paz, Bolivia Population: 1 Million Elevation: 3900-2900 meters Airport in El Alto –< 30 min from downtown –Elevation 4100 m –El Alto pop. 0.5 Million

27. miniHAWC Jordan Goodman Beijing – June 2006 El Alto viewed from Mt. Chacaltaya

28. miniHAWC Jordan Goodman Beijing – June 2006 4806 meters +- 13 meters –South 16 deg 22.381’ –West 68 deg 08.758’ 4443 meters +- 10 meter –South 16 deg 24.837’ –West 68 deg 08.979’ Mt. Chacaltaya Cosmic Ray Laboratory La Paz El Alto Grid on Map is 1 km x 1km Potential Sites Water is plentiful, maybe too much so. Latitude: 16 O 30’ S Longitude: 68 O 11’ W

29. miniHAWC Jordan Goodman Beijing – June 2006 YBJ Laboratory – Tibet, China Elevation: 4300m Latitude: 30 O 13’ N Longitude: 90 O 28’ E Lots of space. Available power. Available water. Tibet Air Shower Array

30. miniHAWC Jordan Goodman Beijing – June 2006 YBJ Laboratory – Tibet, China Also home of ARGO observatory. ARGO utilizes RPC’s for EM particle detection. No Calorimetry.

31. miniHAWC Jordan Goodman Beijing – June 2006 Geomagnetic Cutoff Milagro:3.5 GV Tibet- 13.1 GV La Paz: 12.0 GV Sierra Negra: 7.7 GV Singles rates at sites under consideration are reduced by ~20-30% due to improved geomagnetic cutoff.

32. miniHAWC Jordan Goodman Beijing – June 2006 Triggering and DAQ Milagro DAQ in its current form should be capable of triggering to multiplicities as low as ~80 PMTs. (~1800 Hz) Simulation indicates that we can reconstruct gamma-ray events as small as ~20 PMTs. Potentially huge sensitivity increase to GRBs if DAQ can be easily upgraded.

33. miniHAWC Jordan Goodman Beijing – June 2006 DAQ Upgrade Move to VME TDC bases DAQ. CAEN 1190 Capable of >40MB/s 10-20kHz Readout. Cost ~100k$

34. miniHAWC Jordan Goodman Beijing – June 2006 Costs Facility ~$3M –Excavation, Liner, Building, Roads etc. Water Recirculation System ~$50k Cabling DAQ Upgrade ~$200k Other costs: ~$600k? –Computing, Archiving, Monitoring, Cooling, Shipping… Getting the Water (site dependent) Electrical (site dependent) Communications (site dependent)

35. miniHAWC Jordan Goodman Beijing – June 2006 Summary 15x Sensitivity increase over Milagro ~60mCrab sensitivity (5  in 1year) Mostly proven technology –Leverage $1.5M investment in Milagro equipment –Could construct rapidly if site available. Next Logical Step toward HAWC

36. miniHAWC Jordan Goodman Beijing – June 2006 Conclusion DC2 Catalog (from J McEnery)

37. miniHAWC Jordan Goodman Beijing – June 2006 HAWC: Simulated Sky Map  C&G AGN  Hartmann IR model  known TeV sources  Milagro extended sources  1-year observation

38. miniHAWC Jordan Goodman Beijing – June 2006 Survey Sensitivity 4 min/fov 7 min/fov 1500 hrs/fov

39. miniHAWC Jordan Goodman Beijing – June 2006 Detector Sensitivity (Single Location) miniHAWC HAWC GLAST EGRET Crab Nebula Whipple VERITAS/HESS Current synoptic instruments