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TACTIC & MACE gamma-ray telescopes. Kuldeep Yadav ( For HIGRO collaboration ) Astrophysical Sciences Division Bhabha Atomic Research Centre Mumbai- 400 085, India. TACTIC telescope (TeV Atmospheric Cherenkov Telescope With Imaging Camera). Control room. TACTIC console. - PowerPoint PPT Presentation
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07 Feb, 2009 Rencontres de Moriond 2009 1
TACTIC & MACE gamma-ray telescopes
Kuldeep Yadav( For HIGRO collaboration)
Astrophysical Sciences DivisionBhabha Atomic Research Centre
Mumbai- 400 085, India
07 Feb, 2009 Rencontres de Moriond 2009 2
TACTIC telescope(TeV Atmospheric Cherenkov Telescope With Imaging
Camera)
Controlroom
TACTICconsole
07 Feb, 2009 Rencontres de Moriond 2009 3
TACTIC Parameters• Location : Mt. Abu, Rajasthan
(72.7dE,24.6dN, 1400m asl)• Light collector : ~9.5 sq. meter• Camera FoV : 5.9d x 5.9d (349 pixels)• Trigger FoV : 3.4d x 3.4d• Trigger Criteria : 3NCT (Fast RAM based)• SPE threshold : 7pe• Energy threshold : ~1 TeV• Distributed 4-node DAS using RTOS• Drive Control : SM based (120Ncm)• Observations time : 1170 hr/year( Oct-June)• NIM & CAMAC
R.Koul et. al., Nucl. Instrum. and meth. A., 578(2007) 548
07 Feb, 2009 Rencontres de Moriond 2009 4
Multi-node Data Acquisition System
Semaphore Manager
CAMAC Driver
LEDDriver
GAINCONTROL
HVDRIVER
LEDCAMACSCALER
G A I N C O N T R O L N O D E
SCALER Test HV Test
PCRCCR
QN X NODE #3
HV
QNX NODE # 1
C D C D A T A N O D E
SHAREDMEMORY
CAMAC Driver
Linux NODE # 4
--- Data Processing--- Display--- Data quality check--- Archiving
QNX NODE # 2
CDC DATA - EVENT - CALIBRATION - SKY-NOISE
CAMAC CDC CAMAC TTG`
INTERRUPT HANDLER
- Master Process- Display Manager- Data Storage
TCP - IP
ACE Event
Calibration Event
( From TTG )
LED Driver
Chance Event
Linux NODE # 4Linux NODE #5
--- Data Processing--- Display--- Data quality check--- Archiving
Multi-node DA & CS of TACTIC
07 Feb, 2009 Rencontres de Moriond 2009 5
Mrk 501 observations 1997
0
2
4
6
0
2
4
6
Modified Julian Date
50520 50550 505800
2
4
6 -
Ray
Sig
nal
( cr
ab u
nits
)
CAT
WHIPPLE
TACTIC
HEGRA
Mkn - 501 ( April - May , 1997 )
0
2
07 Feb, 2009 Rencontres de Moriond 2009 6
Crab Nebula Observations (2003-04)
Alpha (deg)
0 9 18 27 36 45 54 63 72 81 90
Nu
mb
er o
f e
ven
ts p
er 9
0
bin
2400
2600
2800
3000
3200
3400
NO OF IMAGES (TOTAL)= 680518 NO OF IMAGES (FILT.) = 26615 % IMAGES SELECTED = 3.91 GAM DOM. EVTS (0-15) = 6081 + 78 COS.BG. EVTS (0-15) = 5121 + 38 EXCESS EVTS (0-15) = 960 + 87 SIGNIFICANCE = 11.05 AVG.BG EVTS./ BIN = 2561 + 19
OBS TIME ( h) = 103.6081 RBL RATE (/h) = 24.71 0.18 GAMMA-RAY RATE (/h) = 9.26 0.84
Gamma-rays :( 960 + 87) Significance : 11.05
Recent observation on Crab Nebula with TACTIC ( Nov.2003 -Feb.2004)
07 Feb, 2009 Rencontres de Moriond 2009 7
Crab Nebula - Differential energy spectrum ( Comparison with other systems )
Energy (TeV)
1 10
Dif
ere
nti
al f
lux
(p
ho
ton
s cm
-2 s
-1 T
eV-1
)
10-16
10-15
10-14
10-13
10-12
10-11
10-10TACTIC FLUX POINTSHEGRA SPECT RUMWHIPPLE SPECTRUMTACTIC BEST FIT SPECTRUM
(3.18 + 0.41) x 10 -11 ( E / 1TEV )-2.65 + 0.11 cm-2 s-1 TeV -1
HEGRA SPECTRUM
TACTIC SPECTRUM
WHIPPLE SPECTRUM
(2.79 + 0.02) x 10 -11 ( E / 1TEV )-2.59 + 0.03 cm-2 s-1 TeV -1
(3.20 + 0.17) x 10 -11 ( E / 1TEV )-2.49 + 0.06 cm-2 s-1 TeV -1
07 Feb, 2009 Rencontres de Moriond 2009 8
TACTIC observation of MrK 421 (2005-06)
07 Feb, 2009 Rencontres de Moriond 2009 9
TACTIC light curve of Mrk 421 (2005-06)
07 Feb, 2009 Rencontres de Moriond 2009 10
Crab & Mrk 421 concurrent Energy Spectra (2005-06)
K.K.Yadav et. al., Astroparticle Physics, 27(2007) 447
07 Feb, 2009 Rencontres de Moriond 2009 11
On-source alpha plot of 1ES2344 + 514 (60 h data during 2004-05)
S.V.Godambe et. al., J.Phys.G:Nucl.Part.Phys. 34(2007) 1683
I(≥1.5 TeV) ≤ 3.84 x 10 -12 ph cm-2s-1
07 Feb, 2009 Rencontres de Moriond 2009 12
Mrk 501 observations (2006) 7.5 sigma in 69 h
2005 observation ~46h
I(≥1 TeV) ≤ 4.62 x 10 -12 ph cm-2s-1
2006 observation ~69h
07 Feb, 2009 Rencontres de Moriond 2009 13
Mrk 501 energy spectrum (2006)
S.V.Godambe et. al., J.Phys.G:Nucl.Part.Phys. 34(2008) 065202
f0=1.66±0.52 x 10-11cm-2s-1TeV-1
ſ = 2.8 ± 0.27
07 Feb, 2009 Rencontres de Moriond 2009 14
H1426+428 observations (2004,06,07) ~150 h
K.K.Yadav et. al., submitted to J.Phys.G:Nucl.Part.Phys.
07 Feb, 2009 Rencontres de Moriond 2009 15
TACTIC & ASM light curves of H1426
07 Feb, 2009 Rencontres de Moriond 2009 16
Project HIGRO an introduction A New Indian initiative in - ray astronomy
Project HIGRO ( Himalayan - Ray Observatory)
Collaborators --- IIA, TIFR and BARC …………………..
7 Element HAGAR wavefront sampling telescope
+ 21m dia. Stereo MACE ( Major Atmospheric Cerenkov
Experiment)
Each telescope element will use a cluster of ~1408 PMTs with a pixel resolution of 0.10 ; FoV ~ 40 x 40.
Aim : Study the sky in the unexplored energy range Eγ > 20 GeV to bridge the gap between the space-based and the ground based detectors.
07 Feb, 2009 Rencontres de Moriond 2009 17
Hanle, Ladakh (32.7d N, 79d E, 4200m asl)
07 Feb, 2009 Rencontres de Moriond 2009 18
Observatory site
10 kmphMed. Wind speed
IIA Campus, HANLE
Location
4200 m asl (~ 600 g cm -2 )
Altitude
32.7 0 N, 78.90 ELat. And Long
8 hrsLeh- Hanle travel
260 KmNearest town
-240 C (at night)
Min. Temp
May - Oct Time for out door work
-20 C (at night)
Med. Temp.
30% Med. Rel. Humidity
full yearAccessibility
Site Characteristics
2m HCT
Telescope site IIA Campus , Hanle 4200 m asl (~ 600 g cm -2 )
HAGAR (1/7)
High altitude related difficulties
07 Feb, 2009 Rencontres de Moriond 2009 19
Advantages of setting up MACE at HANLE
Reduction in threshold energy by a factor of ~ 2.5-3.5 at
Hanle ( ~ 4200m asl ) compared to lower Altitudes sites like Gurushikhar ( ~1700m asl).
Cloud free sky --- Spectroscopic Nights : ~260 nights / yr
Photometric Nights : ~190 night /yr
Year round sky coverage -- Quite a few important
sources cannot be observed at Gurushikhar during June-Sept
due to Monsoon.
Concurrent observations with HAGAR telescope (>60GeV) &
Coordinated multi-wavelength observations with the HCT at Hanle.
Improvement in sensitivity because of being closer to
shower maximum ( images become broader at higher
altitudes).
07 Feb, 2009 Rencontres de Moriond 2009 20
Broad guide lines for designing the MACE telescope
Lower the energy threshold to ~20GeV (Observation altitude, Large light collection area, small coin. gate
width, appropriate pixel size, CPCs, Intelligent trigger generation
scheme)
Employ GHz signal processing using Analog Ring Sampler
Install MACE in the close vicinity of the HAGAR array Improve detection sensitivity by using coincident HAGAR data
Use central pixel for used for optical monitoring of the source ----
photometric observations
Fast repositioning of the telescope --- high energy tails of GRBs.
Operate PMTs at a gain of ~20,000 --- ( use partially moon lit nights)
Improve detection sensitivity – employ a stereo system in a phased manner
07 Feb, 2009 Rencontres de Moriond 2009 21
.
Increase in Cherenkov Photon density with altitude
07 Feb, 2009 Rencontres de Moriond 2009 22
Major mechanical sub-systems of the telescope
Telescope structure material -- Steel – SA-333 Gr 6 (suitable for low temp. applications) Mirror basket structure Aluminum Honey comb panels for mounting mirror facets Active Miror control (AMC) alignment system Camera vessel for housing focal plane instrumentation Drive
control system ( DC servo motors with 17 bit encoders) Track and wheel design concept for azimuth motion (27 m dia) Camera handling and maintenance structure
Total weight ~ 150 MT Overall height of the telescope ~ 45m Operational/ Survival wind speed ~ 45 km/h // 150 km/h Operating temp. ~ -300C to 050C ( Winter) ~ 050C to 300 C (Summer)
Critical design issues Load (Self-weight, 1200 kg camera, Wind load) Deflection, Shadow region, Transportation
07 Feb, 2009 Rencontres de Moriond 2009 23
MACE telescope --- Light collector design
Diameter (area) 2100 cm ( tessellated design – 356 panels) – 337 m2
Focal distance 2500 ( ~ f/1.2 design)
Individual mirror facets
Diamond Milled Al
4 x (050cm X 050cm )
1 x (100cm X050cm )
Configuration Paraboloid with graded focal length panels
X (cm)
-1200 -1000 -800 -600 -400 -200 0 200 400 600 800 1000 1200
Y (
cm)
-1200
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
1200
Zone # 01
Zone # 02
Zone # 03
Zone # 04
Zone # 05
Zone # 06
Zone # 07
Zone # 08
Zone # 09
Zone # 10
Zone # 11
B L A N K
07 Feb, 2009 Rencontres de Moriond 2009 24
Expected PSF of the light collector
Angle of incidence ( deg)
0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75
D 8
0 (
mm
)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
Graded fConstant fDavies-CottonSingle Paraboloid
Pixel Diameter
=0.00 =0.50
=1.00 =1.50 Plate scale :
43.6mm ~ 0.100
Plate scale : 43.6mm =0.10
07 Feb, 2009 Rencontres de Moriond 2009 25
Imaging camera specifications:
X (deg)
-2 -1 0 1 2
Y (
deg
)
-2
-1
0
1
2
Total pixels 1408
Pixels in trigger region 564
Total FoV ~ 4 0 x 4 0
Trigger FoV ~ 2.4 0 x 2. 4 0
Pixel size (at cpc) 45 mm
photo cathode dia 22/29 mm
Imaging camera
Imaging camera Vessel
Size : 2m x 2m x 2.5m
Mass : 1200 kg
Requirement of a good camera design ---
pixel size and camera FoV Pixel size depends upon the differences in the characteristic size of gamma-ray and
hadron generated Cerenkov images.
07 Feb, 2009 Rencontres de Moriond 2009 26
Signal Processing Hardware
• 16 channel module• GHz Sampling• Integrated Camera (all signal processing instrumentation
housed within the camera structure of 2mx2mx1.2m size)• Temperature control of the Camera
during operation and standby condition.
07 Feb, 2009 Rencontres de Moriond 2009 27
Monte Carlo simulation studies
CORSIKA air shower simulation code Energy range -- 1 - 1000 GeV for gamma-rays & e; 10 - 10000 GeV for p & alpha
Observatory altitude : 4200 m asl ( Hanle) LONS background : 3.0 x 10 12 photons m-2 s-1 sr-1
No. of showers generated : 8 x 106 each for γ, p , α & e
Zenith angle : Vertical incidence Impact parameter : 0-400 m for gamma -rays, e & p ; 0-500 m for alpha
Mirror reflectivity, CPC collection efficiency, : Taken into account Atmospheric extinction Trigger FoV : 2.40 x 2.40
Single pixel threshold ~ 4 pe Trigger generation logic : NNQ
07 Feb, 2009 Rencontres de Moriond 2009 28
Monte Carlo simulation studies– Effective collection area
Energy ( GeV)10 100 1000
Eff
ec
tiv
e c
olle
cti
on
are
a (
m
2 )
101
102
103
104
105
106
Gamma Electron
Proton Alpha
07 Feb, 2009 Rencontres de Moriond 2009 29
Monte Carlo simulation studies – Threshold energy estimates
Energy ( GeV)10 100 1000
Dif
fere
nti
al ra
te (
s
-1 G
eV
-1)
10-2
10-1
100
101
102
Gamma
Electron
Proton
Alpha
E(trig) ~ 20 GeV
Ep(trig) ~ 150 GeV
Ee(trig) ~ 20 GeV
E(trig) ~ 500 GeV
07 Feb, 2009 Rencontres de Moriond 2009 30
Preliminary calculations using Hillas parameters
Standard image cleaning procedure picture threshold =4.4pe & Boundary threshold= 2.2pe.
Hillas parameters ( Length, Width, Frac2, Distance, Alpha ) ( Dynamic supercuts with Alpha<80 .)
Detection sensitivity for Crab
Nebula @ 5σ significance
Tmin ~ 13 mins ( @ Size> 530pe -- Eγ > 200
GeV)
Tmin ~ 43 mins ( @ Size>50 pe -- Eγ > 55
GeV)Energy ( GeV)
10 100 1000
Dif
fere
nti
al r
ate
( s
-1 G
eV -1
)
10-6
10-5
10-4
10-3
10-2
10-1
100
101
Trigger threshold ~ 35 GeV
Analysis threshold
@ >50pe ~ 55 GeV
@ >530pe ~ 200 GeV
Size > 50 pe
Size > 530 pe
Trigger
• MACE sensitivity is still preliminary .
• We still have a long way to go to improve this figure !!
07 Feb, 2009 Rencontres de Moriond 2009 31
Implementation status
Funding for 1 MACE element already approved (~ 40 crores ) $ 8 M Telescope mechanical design (~ DDR is completed ) First Light --- 2010 (Single MACE element )
Agenda for ongoing work Prototype 256 pixel camera with ARS –based instrumentation being developed at BARC Camera design optimization (~ FOV and Pixel size --- arrive at the most optimum configuration) Use of WLS dyes for improving the QE of PMTs Include PMT temporal response in MC simulations. Use pulse profile information also for improving γ /h segregation
Achieve Tmin ~ <2 min @ E γ>100 GeV using conventional analysis and
simultaneously use alternative γ /h segregation
methodologies for improving the sensitivity @ E γ < 100 GeV
Simulation for stereo MACE Repeat simulations at different zenith angles & also at lower altitude
(~1600 m) for quantifying the quantum of sensitivity improvement at
higher altitude.
07 Feb, 2009 Rencontres de Moriond 2009 32
.
THANK YOU