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					              miniHAWC
                             mini-
                g



                             High
                             Altitude
                             Water
                             Cherenkov
                             experiment
              Jordan Goodman
           University of Maryland
miniHAWC                         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.

   miniHAWC                         Jordan Goodman
                                   Beijing – June 2006
                              Detector Layout




Milagro:                               HAWC:                                     miniHAWC:
450 PMT (25x18) shallow (1.4m) layer   5625 or 11250 PMTs (75x75x(1 or 2))       841 PMTs (29x29)
273 PMT (19x13) deep (5.5m) layer      Single layer at 4m depth or 2 layers at   5.0m spacing
175 PMT outriggers                     Milagro depths                            Single layer with 4m depth

Instrumented Area:       ~40,000m2     Instrumented Area:        90,000m2        Instrumented Area:      22,500m2
PMT spacing:             2.8m          PMT spacing:              4.0m            PMT spacing:            5.0m
Shallow Area:            3500m2        Shallow Area:             90,000m2        Shallow Area:           22,500m2
Deep Area:               2200m2        Deep Area:                90,000m2        Deep Area:              22,500m2
              miniHAWC                                                            Jordan Goodman
                                                                                 Beijing – June 2006
                          Altitude



                  4300m

                 2600m




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




                                      1.5 m
Milagro: 2 layers at depths




                                                                     5.5 m
         1.5m – “Air Shower” Layer
         5.5m – “Muon” Layer
                                                   2.8 m

miniHAWC: Single intermediate layer
opaque curtains between cells




                                              5m
                          4m




         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




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




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 g/hadron discrimination variable for
  HAWC/miniHAWC that excludes the core location.

  CMilagro = (nPMTs > 2 PE)/(Max “muon layer” hit)

  CminiHAWC =(nPMTs > 2 PE)/(Max “muon layer” hit >20m from
    core)


      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




     miniHAWC                                    Jordan Goodman
                                                Beijing – June 2006
                    miniHAWC Sensitivity
Significance from                         Energy (Crab Spectrum, nTop/cxPE>5.0., q<30O)
Crab Transit (~5 hr) 4s
                                               nTrig>50
Crab signif/year          80s                  Ethr~700 GeV

5s point source
sensitivity reach       ~60mCrab                                 nTrig>200
of 1 year survey                                                 Ethr~2TeV



Energy Resolution ~30% above median
                                                S/B (hard cuts) ~ 1:1 for Crab
Angular Resolution 0.25O-0.40O                  Typical day 20 excess on 25 bkg
                    Q (sig/√bg) ( miniHAWC/Milagro) = 15
                                 Single layer doesn't limit sensitivity
         miniHAWC                                                  Jordan Goodman
                                                                  Beijing – June 2006
               Angular Resolution

             s = ~0.4o         s = ~0.25o




n Trigger = 50           n Trigger = 200


  miniHAWC                        Jordan Goodman
                                 Beijing – June 2006
                     g/ hadron Separation
           Cut: nTop/cxPE>5.0          Cut: nTop/cxPE>5.0
           Eff g = 34%                 Eff g = 56%
           Eff CR= 3%                  Eff CR= 1.5%




 Hess                               Q Factor (sig/√bg)
                                    Cuts      soft hard
               eg = 56% -> 28%
               eCR= 3% -> 0.4%      miniHawc 2          4.5
                     (shape only)
                                    Hess       3.2 4.4

miniHAWC                                       Jordan Goodman
                                              Beijing – June 2006
        Gamma/Hadron Separation
                               30 GeV   70 GeV                230 GeV
                     Gammas




Size of miniHAWC
                               20 GeV   70 GeV                 270 GeV
                     Protons




Size of Milagro
  deep layer

          miniHAWC                                Jordan Goodman
                                                 Beijing – June 2006
               Effective Area
           Gamma Area: q<30o   nTop/cxPE>5.0    Dq<1.0O

           200 PMT Trigger
           80 PMT Trigger
           20 PMT Trigger                      Pond Area




miniHAWC                                          Jordan Goodman
                                                 Beijing – June 2006
 Comparison of Effective Areas




                  50 Tube
                  Trigger




miniHAWC                     Jordan Goodman
                            Beijing – June 2006
  Sensitivity Increase from
    Milagro to MiniHawc

• 15x Sensitivity increase over Milagro
  ~3x from Altitude, Area
  ~3x from g/hadron separation
  ~1.5x from Angular resolution

• ~60mCrab sensitivity (5s in 1year)




   miniHAWC                          Jordan Goodman
                                    Beijing – June 2006
                   GRB Sensitivity
   Milagro
                                             miniHAWC




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)

       miniHAWC                                           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.

        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

                               4.5-5.0 m                     6m


                       150m

     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$
                                     170m             170m
Total facility cost ~2.5-3.0M$




            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.


    miniHAWC            Jordan Goodman
                       Beijing – June 2006
             Sierra Negra, Mexico




Elevation = 4030m
Latitude = 19O 00’N
Longitude = 97O 17’ W

  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




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




miniHAWC                       Jordan Goodman
                              Beijing – June 2006
    Potential
     Sites                                    Mt. Chacaltaya
                                              Cosmic Ray
                                              Laboratory
4806 meters +- 13 meters
    – South 16 deg 22.381’
    – West 68 deg 08.758’

                                             Grid on Map
                                             is 1 km x 1km
4443 meters +- 10 meter
    – South 16 deg 24.837’
    – West 68 deg 08.979’


 Water is plentiful, maybe
 too much so.                                 La Paz
 Latitude: 16O 30’ S
 Longitude: 68O 11’ W
                      El Alto

           miniHAWC              Jordan Goodman
                                Beijing – June 2006
  YBJ Laboratory – Tibet, China
Elevation: 4300m
Latitude: 30O 13’ N    Tibet Air Shower Array
Longitude: 90O 28’ E

Lots of space.
Available power.
Available water.




       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.




         miniHAWC         Jordan Goodman
                         Beijing – June 2006
            Geomagnetic Cutoff
                      Milagro:3.5 GV       Sierra Negra: 7.7 GV




            Tibet- 13.1 GV
                              La Paz: 12.0 GV


Singles rates at sites under consideration are reduced by ~20-30%
due to improved geomagnetic cutoff.
 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.
   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$




     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)
   miniHAWC                                Jordan Goodman
                                          Beijing – June 2006
                 Summary

• 15x Sensitivity increase over Milagro


• ~60mCrab sensitivity (5s in 1year)

• Mostly proven technology
  – Leverage $1.5M investment in Milagro equipment
  – Could construct rapidly if site available.

• Next Logical Step toward HAWC

    miniHAWC                              Jordan Goodman
                                         Beijing – June 2006
                   Conclusion




      DC2 Catalog (from J McEnery)



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




miniHAWC            Jordan Goodman
                   Beijing – June 2006
             Survey Sensitivity




                                      7 min/fov
                          4 min/fov



           1500 hrs/fov                           1500 hrs/fov




miniHAWC                                                    Jordan Goodman
                                                           Beijing – June 2006
Detector Sensitivity (Single
         Location)


           EGRET




                   GLAST




miniHAWC                    Jordan Goodman
                           Beijing – June 2006

				
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