los alamos national laboratory adelaide, australia. december 2006 gus sinnis synoptic tev telescopes...

Gus Sinnis Los Alamos National Laboratory Adelaide, Australia. December 2006

Synoptic TeV Telescopes

Results from Milagro

Plans for HAWC


Milagro

8 meters

e

80 meters

50 meters

• A Water Cherenkov detector.• Reconstruct shower direction to 0.3-0.7o from

the timing shower front.• Reject background by detecting penetrating

component of hadronic showers• Field of view is ~2 sr • Duty factor ~95%• Trigger rate ~1700 Hz (6 Mbytes/sec)

Milagro Cross Section Schematic


Milagro with Outriggers

175 Outrigger tanks (Tyvek lined – water filled)2.4m diameter, 1m deep34,000 m2 enclosed areaCompleted in May 2003


Background Rejection in Milagro

Proton MC Proton MC

Data Data MC MC

Hadronic showers contain penetrating component: ’s & hadrons

– Cosmic-ray showers lead to clumpier bottom layer hit distributions– Gamma-ray showers give smooth hit distributions


• Parameterize “clumpiness” of the bottom layer hits

– Compactness

• Require C > 2.5• 50% gammas & 10% hadrons• Sensitivity improved by 1.6

• Require A4 > 3.0• 20% gammas & 1% hadrons• Sensitivity further improved by 1.4

Background Rejection (Cont’d)

( )mxPE

nFitfOut+fTop=A

∗4

mxPE

nb2=C

mxPE: maximum # PEs in bottom layer PMT

nb2: # bottom layer PMTs with 2 PEs or more

fTop: # fraction of hit PMTs in Top layer

fOut: # fraction of hit PMTs in Outriggers

nFit: # PMTs used in the angle reconstruction


Spectral DeterminationA4 is related to energy2-20 TeV useful range

Parameterization of events


Crab Spectrum

Exponential cut off energy is Ec = 31.0 TeV (w/large error

bars)

Preliminary


Milagro Sky Survey

Crab NebulaCygnus Region MRK 421

200

3 (p

re-o

utrig

ger

)20

06

(pos

t-o

utri

gger

)


Sig

nifi

can

ce

GP diffuse excess clearly visible from l=25° to l=90° Cygnus Region shows extended excess FCygnus ~ 2 x Fcrab

120 square degrees l (65,85), b (-3,3)

The Galactic Plane


The Cygnus Region Contours are GALPROP

pion model Crosses are EGRET

(unidentified) sources TeV/matter correlation good

Chance noncorrelation 1.5x10-6 Brightest TeV Region

– MGRO J2019+37– ~0.5 Crab @ 12 TeV– Extent = 0.32 ± 0.12 deg.– Coincident with 2

EGRET sources (unID)• PWN G75.2 + 0.1• Blazar (B2013+370)

– Energy Analysis in progress

Flux @ 12.5 TeV= E2 dN/dE = (4.18 ± 0.52stat ± 1.26sys) x 10-10 TeV cm-2 s-1 sr-1

(excluding new source & assuming E-2.6) ~3.5 Crab in 180 sq. degree region


Cygnus Region: Diffuse Gamma Rays

Strong & Moskalenko

GALPROP model of Cygnus Region

• Strong & Moskalenko optimized model– Increase 0 and IC

component throughout Galaxy

– Milagro 2-6x above prediction (optimized-standard models)

– Unresolved sources?– Cosmic-ray

accelerators?

standard

optimized

Inverse Compton

Pion

bremsstrahlung


Cygnus Region: Multi-wavelength

0.1 GeV

Milagro 10 TeV gamma-ray

Radio Continuum (408MHz)

Atomic Hydrogen

Radio Continuum (2.5GHz)

Molecular Hydrogen

X-Ray

Gamma-Ray (100 MeV)

Gamma-Ray (10 TeV)

Radio Continuum (408MHz)

Atomic Hydrogen

Radio Continuum (2.5GHz)

Molecular Hydrogen

X-Ray

Gamma-Ray (100 MeV)

Gamma-Ray (10 TeV)


High Altitude Water Cherenkov Telescope

HAWC

A proposal to redeploy the Milagro PMTs

with Wider Spacing

at Higher Altitude

10-15 times more sensitive than Milagro


HAWC Goals

• Complete hemisphere survey to 25 mCrab– After 4 years

• Detailed map of Galactic diffuse emission• Search for extended sources• Detect AGN transients

– 4 Crab in 15 minutes

• Detect GRBs to 1/100 keV fluence• Spectra to the highest energies (~100 TeV)• Contemporaneous with GLAST, HESS,

VERITAS, & IceCube


Altitude Effect

4100m

2600m

Difference between 2600m (Milagro) and 4100m:~ 6x number of particles~ 2-3x lower median energy


Detector Layout

Milagro:450 PMT (25x18) shallow (1.4m) layer273 PMT (19x13) deep (5.5m) layer175 PMT outriggers

Instrumented Area: ~40,000m2

PMT spacing: 2.8mTotal Area: 3500m2

det Area: 2200m2

HAWC:900 PMTs (30x30)5.0m spacingSingle layer with 4m depth

Instrumented Area: 22,500m2

PMT spacing: 5.0mTotal Area: 22,500m2

det Area: 22,500m2

HAWCMilagro


Detector Layout

Milagro: 2 layers at depths1.4m – “Air Shower” Layer6.0m – “Muon” Layer

HAWC: Single intermediate layerOpaque curtains between cells

4m

6 m

5 m

2.8 m

1.4

m


Curtains• HAWC single muon rate = ~1 MHz • Install curtains to optically isolate the PMTs.

• Avoid triggering on single muons

• Intrinsic Gamma hadron separation


HAWC Trigger Rate

• Multiplicity trigger at ~80 PMTs gives same CR trigger rate as Milagro at 50 PMTs• Much higher Gamma-ray rate.

Milagro

HAWC

Gamma-Ray Rate


= ~0.4 deg = ~0.25 deg

Angular Resolution

nTrigger = 50 PMTs nTrigger = 200 PMTs


Gamma/Hadron Separation

Gam

mas

Pro

ton

s30 GeV 70 GeV 230 GeV

20 GeV 70 GeV 270 GeVSize of HAWC

Size of Milagro deep layer Energy Distribution at ground level



Circles are EM particles > 1 GeV Circles are ’s & hadrons > 1 GeVCircles are 30m radius (~area of Milagro bottom layer)

prot

ons

gam

mas



nHit/cxPE>5.0Eff = 34%Eff CR = 3%

nHit/cxPE>5.0Eff = 56%Eff CR = 1.5%

Q Factor (sig/√bg)

Cuts soft hard

HAWC 2.0 4.5

HESS 3.2 4.4

HESS

= 56% -> 28%CR= 3% -> 0.4%

(shape only)


Effective Area

Gamma Area: <30o nTop/cxPE>5.0 <1.0O

200 PMT Trigger80 PMT Trigger20 PMT Trigger

Area ofGLAST

Detector Size


HAWC Point Source Sensitivity

Q (sig/√bg) (HAWC/Milagro) = 15

Significance from

Crab transit (4 hr) ~5

Crab 1 year ~100

Energy Resolution ~30% above median

Angular Resolution 0.25O-0.5O

S/B (hard cuts) ~ 1:1 for CrabSingle transit: 20 excess / 25 bkg

HAWCHAWC II

GLAST

EGRET Crab Nebula

WhippleVERITAS/HESS

Current synoptic

instruments


Sensitivity vs. Source Spectrum

Milagro

HESS

HAWC


Sensitivity vs. Source Size


Sky Surveys


GRB Sensitivity

Fluence Sensitivity to 10s GRB.Both Milagro and HAWC can “self trigger” and generate alerts in real time.GRB rate in FOV ~100 GRB/year (BATSE rate)

Milagro HAWC


Pond Design

• Fiducial volume: 150m x 150m x 4m

• Actual size: 170m x 170m x 6m

• 1:1 slope at perimeter

• 6 m depth to allow for 4m over PMTs.

• Total volume: 115 Ml

170m

150m

4.5-5.0 m 6m


Building Construction

• Prefabricated steel building– Components manufactured

at factory.– Shipped to site (~9 trucks)– Beams bolted not welded.– Cost ~1.5M$ (not installed)

• Building installation ~400 k• Pond excavation ~300 k• Liner cost ~600 k

Total facility cost ~3.5 MTotal Cost ~5.2 M

162m 162m


YBJ Laboratory – Tibet, ChinaElevation: 4300mLatitude: 30O 13’ NLongitude: 90O 28’ E

Lots of space.Available power.Available water.

Tibet Air Shower Array


Sierra Negra, Mexico

•3

•1

•2

•LMT

•1 km

•N

Elevation = 4100m or 4300mLatitude = 19O 00’NLongitude = 97O 17’ W


HAWC Status and Timeline

• A proposal for a total project cost ~$5M has been submitted by the US groups to NSF– A proposal will be sent to DoE– Mexican Collaborators have submitted a proposal to

their funding agency

• A final site decision will be made this year• If approved:

– Next year we will do site specific design– Start construction in 2008– Complete construction and start data taking in 2010


Conclusion• Milagro has made significant discoveries:

– Discovery of diffuse TeV gamma rays from the Galactic plane – Discovery of diffuse TeV gamma rays from the Cygnus region– Discovery of a new extended TeV source in the Cygnus region

• HAWC can attain high sensitivity over an entire hemisphere– ~15 times the sensitivity of Milagro– ~5 sigma/day on the Crab– 30 mCrab sensitivity over entire

hemisphere– Unsurpassed sensitivity to extended

sources– Unique TeV transient (AGN/GRB)

detector– Can be built quickly @ low cost

los alamos national laboratory adelaide, australia. december 2006 gus sinnis synoptic tev telescopes...

Documents

gus sinnis cygnus region

hawc slide

postoutrigger slide

cygnus region contours

smooth hit distributions

layer pmts

galactic plane slide

angle reconstruction