minihawc jordan goodman beijing – june 2006 jordan goodman university of maryland mini- high...
TRANSCRIPT
Jordan GoodmanBeijing – June 2006
miniHAWC
Jordan GoodmanUniversity of Maryland
mini-High Altitude Water Cherenkov experiment
miniHAWC
Jordan GoodmanBeijing – June 2006
miniHAWC
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.
Jordan GoodmanBeijing – June 2006
miniHAWC
Detector Layout
Milagro:450 PMT (25x18) shallow (1.4m) layer273 PMT (19x13) deep (5.5m) layer175 PMT outriggers
Instrumented Area: ~40,000m2
PMT spacing: 2.8mShallow Area: 3500m2
Deep Area: 2200m2
HAWC:5625 or 11250 PMTs (75x75x(1 or 2))Single layer at 4m depth or 2 layers atMilagro depths
Instrumented Area: 90,000m2
PMT spacing: 4.0mShallow Area: 90,000m2
Deep Area: 90,000m2
miniHAWC:841 PMTs (29x29)5.0m spacingSingle layer with 4m depth
Instrumented Area: 22,500m2
PMT spacing: 5.0mShallow Area: 22,500m2
Deep Area: 22,500m2
Jordan GoodmanBeijing – June 2006
miniHAWC
4300m
2600m
Difference between 2600m (Milagro) and 4300m (Tibet):~ 6x number of particles~ 2x lower energy threshold
Altitude
Jordan GoodmanBeijing – June 2006
miniHAWC
Detector Layout
Milagro: 2 layers at depths1.5m – “Air Shower” Layer5.5m – “Muon” Layer
miniHAWC: Single intermediate layeropaque curtains between cells
4m
5.5
m
5 m
2.8 m
1.5
m
Jordan GoodmanBeijing – June 2006
miniHAWC
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
Jordan GoodmanBeijing – June 2006
miniHAWC
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
Jordan GoodmanBeijing – June 2006
miniHAWC
Gamma/Hadron Separation
Lateral distribution of EM energy and muons.
Jordan GoodmanBeijing – June 2006
miniHAWC
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.
CMilagro = (nPMTs > 2 PE)/(Max “muon layer” hit)
CminiHAWC =(nPMTs > 2 PE)/(Max “muon layer” hit >20m from core)
Jordan GoodmanBeijing – June 2006
miniHAWC
Triggering with Curtains
• Multiplicity trigger at ~70 PMTs gives same trigger rate as Milagro at 50 PMTs• Much higher Gamma area.
protonsgammas
Jordan GoodmanBeijing – June 2006
miniHAWC
Energy (Crab Spectrum, nTop/cxPE>5.0., <30O)Significance fromCrab Transit (~5 hr) 4
Crab signif/year 80
5 point source sensitivity reach ~60mCrabof 1 year survey
Energy Resolution ~30% above median
Angular Resolution 0.25O-0.40O
S/B (hard cuts) ~ 1:1 for CrabTypical day 20 excess on 25 bkg
miniHAWC Sensitivity
Q (sig/√bg) ( miniHAWC/Milagro) = 15Single layer doesn't limit sensitivity
nTrig>50
Ethr~700 GeV
nTrig>200
Ethr~2TeV
Jordan GoodmanBeijing – June 2006
miniHAWC
= ~0.4o = ~0.25o
Angular Resolution
n Trigger = 50 n Trigger = 200
Jordan GoodmanBeijing – June 2006
miniHAWC
/ hadron Separation
Cut: nTop/cxPE>5.0Eff = 34%Eff CR= 3%
Cut: nTop/cxPE>5.0Eff = 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
Jordan GoodmanBeijing – June 2006
miniHAWC
Gamma/Hadron Separation
Gammas
Protons
30 GeV 70 GeV 230 GeV
20 GeV 70 GeV 270 GeVSize of miniHAWC
Size of Milagro deep
layer
Jordan GoodmanBeijing – June 2006
miniHAWC
Effective AreaGamma Area: <30o nTop/cxPE>5.0 <1.0O
200 PMT Trigger80 PMT Trigger20 PMT Trigger Pond Area
Jordan GoodmanBeijing – June 2006
miniHAWC
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)
Jordan GoodmanBeijing – June 2006
miniHAWC
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)
MilagrominiHAWC
Jordan GoodmanBeijing – June 2006
miniHAWC
The Diffuse Galactic Plane in miniHAWC and HAWC
Use Neutral H map to trace out VHE Gamma-Ray flux. Normalize to Milagroobserved TeV diffuse emission from the Galactic plane.
Jordan GoodmanBeijing – June 2006
miniHAWC
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
Jordan GoodmanBeijing – June 2006
miniHAWC
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 170m
Jordan GoodmanBeijing – June 2006
miniHAWC
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.
Jordan GoodmanBeijing – June 2006
miniHAWC
Sierra Negra, Mexico
Elevation = 4030mLatitude = 19O 00’NLongitude = 97O 17’ W
Jordan GoodmanBeijing – June 2006
miniHAWC
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
Jordan GoodmanBeijing – June 2006
miniHAWC
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. ChacaltayaCosmic Ray Laboratory
La Paz
El Alto
Grid on Mapis 1 km x 1km
Potential Sites
Water is plentiful, maybe too much so.
Latitude: 16O 30’ SLongitude: 68O 11’ W
Jordan GoodmanBeijing – June 2006
miniHAWC
YBJ Laboratory – Tibet, China
Elevation: 4300mLatitude: 30O 13’ NLongitude: 90O 28’ E
Lots of space.Available power.Available water.
Tibet Air Shower Array
Jordan GoodmanBeijing – June 2006
miniHAWC
YBJ Laboratory – Tibet, China
Also home of ARGO observatory.
ARGO utilizes RPC’s for EM particle detection.
No Calorimetry.
Jordan GoodmanBeijing – June 2006
miniHAWC
Geomagnetic Cutoff
Milagro:3.5 GV
Tibet- 13.1 GVLa 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.
Jordan GoodmanBeijing – June 2006
miniHAWC
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.
Jordan GoodmanBeijing – June 2006
miniHAWC
DAQ Upgrade• Move to VME TDC bases DAQ.
• CAEN 1190• Capable of >40MB/s • 10-20kHz Readout.• Cost ~100k$
Jordan GoodmanBeijing – June 2006
miniHAWC
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)
Jordan GoodmanBeijing – June 2006
miniHAWC
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
Jordan GoodmanBeijing – June 2006
miniHAWC
HAWC: Simulated Sky Map
C&G AGN
Hartmann IR model
known TeV sources
Milagro extended sources
1-year observation
Jordan GoodmanBeijing – June 2006
miniHAWC
Survey Sensitivity
4 m
in/fo
v
7 m
in/fo
v1500 hrs/fov1500 hrs/fov