1. Status of HAGAR B S Acharya (on behalf of HAGAR collaboration)
Tata Institute of fundamental Research
(on behalf of HAGAR collaboration)
IIA, TIFR, SINP, BARC
5th WAPP , Dec 14-16, 2010

2. Advantages of setting up Atmospheric Cherenkov
experiment at high altitude
Higher Cherenkov photon
density at higher altitude
Lower atmospheric
attenuation of Cherenkov
photons
Lower energy threshold
at higher altitudes
Interesting physics issues:
more sources can be observed,
cutoffs in spectra of Active Galactic
Nuclei, pulsars
Overlapping observations with FERMI
Phase 1: HAGAR (IIA+TIFR) 7 element WS
array (non-imaging); Now operating
Phase 2: 21 m Dia MACE (BARC) imaging Tel.
Expected in 2011
Phase 3: MACE-II Stereo imaging; 2012+

3. Latitude: 32° 46΄ 46˝ N Longitude : 78° 57΄ 51˝ E Altitude : 4300 m
IAO, Hanle N
HEGRO, Pachmarhi
Latitude: 32° 46΄ 46˝ N
Longitude : 78° 57΄ 51˝ E
Altitude : 4300 m

4. First HAGAR Telescope at Hanle
2005
First HAGAR Telescope at Hanle

5. Data acquisition and Telescope control

7. All 7 telescopes were commissioned Array is operating
HAGAR
All 7 telescopes were commissioned
Array is operating
Latitude: 32° 46΄ 46˝ N
Longitude : 78° 57΄ 51˝ E
Altitude : 4300 m 7

8. Status of HAGAR HAGAR array was operational in Sept 2008.
After few engineering runs regular observations were started since October 2008
(Shutdown 3 months in , 2 months ,
aiming for 0 months in onwards)
Upgrade/Modifications to various sub-systems of HAGAR were also undertaken in addition to data analysis
-These upgrades were partly planned & partly from feed back from data collected.
Instrument upgrade
Calibrations (NSB monitoring, Relative Time offsets…)
Software (DAQ & Telescope control)
Data analysis methods/procedure

9. Instrument Development
Mechanical – lid for Telescope (IIA)
Alignment (vertical position & mirror orientation )
HV control- SY1527LC was bought
Trigger system (Version 0  Version 3)
Monitoring – Night Sky, Low Voltage
Data acquisition system
Acqiris Flash ADC parallel system, Data Format,
Prog. Disc. ,Delay Gen, Offset measurement
Towards Automation for remote operation

10. Coming soon - HTL version #3
HAGAR Trigger Logic
Custom designed for HAGAR trigger logic
Trigger and Chance trigger sections
Accepts 7 NIM inputs for trigger and 7 diff ECL inputs for Chance
Any N fold or selected combinations jumper options common to both sections
supports GATE to QDC,Latch, RTC latch in, TDC start, Vetoed & un vetoed trigger, chance trigger, Clear
Veto in signal vetoes the Trigger section
Version #1 – April 2009
Version #2 – April 2010
Coming soon - HTL version #3

11. 8 Channel Programmable Digital Delay Generator
Delays output by programmed delay wrt to leading edge of input -- AD9500
Inputs are NIM type and Maskable
Outputs are NIM , (diff ECL or diff LVDS : FRC16) and Maskable
Common external input or SW trigger input
Common Trigger out
Single Channel prototype worked fine.
8 Ch module has problems – interference
PCB is being redesigned – added ground layers

12. 8 Chl Programmable Discriminator Module
The Discriminator threshold is programmable
8 channel analog inputs.
Front panel width control
Front panel common test point for measure of set Thresholds of 8 channels selected by Thumbwheel
CAMAC interface
Since
July 13,2010
Sharma et al., Jour of Institute of Engg, Jan 2010.

13. Calibrations/Monitoring…..
Monitoring – Night Sky, Low Voltage
NSB Measurement
(with Prog. Disc many measurements possible)
12 Measurements in Novemebr 2010
13 measurements in July 2010 – (1.17+/-0.22 )E8 ph/cm2/s/sr
3 measurements in July (0.82 +/-0.14)E8 ph/cm2/s/sr
Hagar PMT- Nov 2008 – (1.91+/-0.05)E8 ph/cm2/s/sr
(Refer to Note by BBSingh, Nawang, Phunchok)
SKY quality meter – July 2010
Internal note by BBSingh et al. 2010
Low Voltage monitoring system –μcontroller based
Internal note by Sandeep kumar et al., 2010

14. Software Upgrade Telescope control and orientation
Modified algorithm for Vertical position and near vertical position.
New bright star scans  overall pointing accuracy ~0.2 deg.
Data acquisition system
Acqiris Flash ADC ; a parallel DAQ system,
Data Format  New hardware - for eg. Prog. Disc.
Missing events at high trigger rates are understood.
For details refer to Note by Kiran Gothe et al
Internal note by B K Nagesh et al. 2010

15. Centre represents focal point of each mirror and Markers represent observed positions of the star

16. DATA (Sept 08 to Sept 2010) source ON (hrs) OFF(hrs) Crab 82.6 73.5
Geminga
59.4
41.4
Mkn 421
74.9
87.8
Mkn 501
48.8
52.5
1ES
51.7
56.9
3C454
13.3
12.1
MGRO
12.6
11.9
LSI (X-ray Binary)
8.3
7.7
PSR007+73
2.4
2.8
M87
2.0
2.7
Dark region (fake source)
79.18
Calibration (Fixed angle)
35.1

17. Monte Carlo Simulation of Extensive Air Showers
CORSIKA package used for simulations of extensive air showers
initiated by -rays and cosmic ray particles
CORSIKA simulates interactions and
decays of hadrons, air nuclei, muons,
electrons and photons in atmosphere
Tracks down all the particles and
photons in the shower to observation
level
Simulates Cherenkov emission
caused by relativistic charged
particles in shower 
Simulation of HAGAR array response
to Cherenkov light using our own code
e+ / e-
+ / -
hadrons

18. CORSIKA Inputs : Cosmic rays : within 3 around vertical
Primary type and energy
Arrival angle of primary
-rays : vertical
Cosmic rays : within 3 around vertical
Impact parameter : m
Altitude of observation level and geomagnetic field
Hanle altitude : 4.3 kms
Telescope array geometry
Wavelength range : nm
Wavelength dependent absorptions of Cherenkov photons :
atmospheric absorption, mirror reflectivity,
photo-tube quantum efficiency : peak 24% at 400 nm
Output :
Arrival time, direction and position of Cherenkov photons
hitting telescopes

19. Details of Spectral Shapes Used for Simulations
For -rays : (20 GeV – 5 TeV)
J(E) = 3.2  (E TeV) m-2 s-1 TeV-1
For protons : (50 GeV – 5 TeV)
J(E) = (E TeV)-2.7 m-2 s-1 sr-1 TeV-1
For  particles : (100 GeV – 10TeV)
J(E) = (E TeV)-2.7 m-2 s-1 sr-1 TeV-1
For electrons : ( 50 GeV – 5 TeV)
J(E) = (E GeV)-3.3 m-2 s-1 sr-1 GeV-1 19

20. Simulation of Detector Response
Site and instrument related parameters
Night sky background : 2  108 ph cm-2 s-1 sr-1
Field of view : 3 FWHM
Phototube response :
Gain = 1.5  106
Pulse shape : Gaussian with rise time 2 ns and width 3.3 ns
Attenuation of pulse in coaxial cables :
30 m LMR-Ultraflex-400, 55m RG213
Pulse amplification : factor of 10
Discriminator thresholds : ~220 mV for telescope pulses
Trigger generation criteria : at least 4 telescope pulses
out of 7 crossing threshold 20

21. Simulated Sample Vertically incident showers Species
Energy range (GeV)
No. of showers
No. of triggers
Duration
(s)
-rays
3,40,000
4,080
37,064
protons
23,89,810
~60 lakhs
2,543
~6000
266.0
~660
particles
1,00,000
52.7
electrons
2,697
Inclined showers
15 deg : -rays – 2,00,000 showers
protons – 2,00,000 showers
30 deg : -rays – 2,00,000 showers
protons – 2,00,000 showers

22. Performance Parameters of HAGAR
Trigger condition
No. of events
Energy threshold (GeV)
Rate (/min)
Collection area (m2)
 3 Tel.
6113
180
9.9
5104
 4 Tel.
4080
210
6.6
4104
 5 Tel.
2591
240
4.2
3104
 6 Tel.
1621
2.6
2104
7 Tel.
961
300
1.6
1104
Performance parameters for inclined showers will be available soon

23. Performance Parameters of HAGAR
Trigger rate :
Protons 9.6 Hz, including  particles and electrons 13.0 Hz
Observed trigger rate = 14 Hz
Simulations to be repeated for other trigger rates Hz
varying PMT gain and NSB
Energy Threshold :

24. Sensitivity

25. Simulations are compared with Data
to validate the Monte Carlo Simulations and
decide cuts on data for signal extraction
Comparison of trigger rates
Comparison of rate-threshold curves: night sky pulse height spectrum
TDC : comparison of Space angle distributions
QDC : comparison of total ADC charge – to be taken up
FADC: comparison – just started

28. Arrival Direction Profiles

29. The Crab field-of-view of HAGAR
Blue star
Mag= 3
3°17'

30. Data Analysis Methods Dark regions: PRELIMINARY
Time offsets (TZERO) – trigger dependant
Cuts on data based on zenith angle and
azimuth
ON-Off Normalisation region
Normalisation scheme
QDC data -
Acqiris data – Flash ADC data
PRELIMINARY
(April-May 2009)
Data Analysis Methods
85 % cut

32. Preliminary Results Crab nebula :
Estimate of Crab flux from HAGAR is consistent with other experiments

33. Some earlier results on Crab
First simultaneous detection of PeV energy burst from the Crab Nebula - B. S. Acharya, M. V. S. Rao, K. Sivaprasad, B. V. Sreekantan & P. R. Vishwanath Here we report the simultaneous detection on 23 February 1989, by experiments in the Kolar Gold Fields
A very high energy   -ray burst from the Crab pulsar
P. N. Bhat, P. V. Ramanamurthy, B. V. Sreekantan & P. R. Vishwanth
Tata Institute of Fundamental Research, Homi Bhabha Marg, Bombay , India
The Crab pulsar, ..In our recent observations, we identified a 15-min interval on 23 January 1985 during which pulsed TeV   -rays were detected at a 5.1 sigma level at the same phase as the radio main pulse.                                                                                                       

35. HAGAR data on MKN 421 in Feb 2010(Prelimiary)
Mjd Rate/min
/- 3.7
/-3.7
/-3.7
Total duration ~550 mins excess number of on source events = Mean gamma rate = /- 1.0 / minute

36. HAGAR (preliminary) + others

37. FERMI Detected Pulsars
COSB/SAS2:02 CGRO:07 FERMI:54+
54+ Pulsars
08 are millisecond Pulsars and Old (Char age ~ 106 kyr)
All millisecond pulsars have their radio counterparts.
Outof 54 Pulsars, 37 are visible for HAGAR telescopes.
(Declination angle -35 deg to 80)
24 gamma ray pulsars have been detected by Fermi-LAT
in the blind search.
31 Pulsars are young and isolated.
21 Pulsars are with spectral index in the range 0.5 – 1.5
12 Pulsars with E_dot > 100x1034 ergs/sec.

38. Crab Pulsar Results
Duration=76 hours

39. Crab Pulsar Results
Duration=76 hours

40. Crab Pulsar Results
P1+P2
P1+P2 P1 P2

41. Geminga Pulsar Results
Duration=49 hours

42. Geminga Pulsar Results
P1+P2 P1 P2

43. Pair selection along with run selection
More accuracy in data selection
Doing space angle analysis after HA selection only
Rejection factor known → efficiency of our cuts
Not “disturbed” by bad events which are not in the common HA range
Easier to compare with simulation
BUT:
- Hardware threshold different in ON and OFF
- How to balance changes in HV → gains of PMTs...?

45. Acqiris 8-bit flash ADCs
Tel. 1
Acqiris 8-bit flash ADCs
DC271A – 1GHz
(since spring 2009)
Tel. 2
Tel. 3
Run cb518_280909
DC271A – 1GHz)
Tel. 4
Tel. 5
Tel. 6
Tel. 7
Trigger
1000 ns samples
- 128 counts ~ (- 8) mV

46. Pedestal from 40 first nanoseconds from Flash ADCs

48. Conceptual design of the MACE telescope
Conceptual design of the MACE telescope

49. Major Atmospheric Cherenkov Experiment (MACE)
Future Prospects
Major Atmospheric Cherenkov Experiment (MACE)
Second stage of HIGRO collaboration
(IIA, BARC, SINP and TIFR)
Initially single imaging telescope of dia 21 m
cluster of 832 PMTs with pixel resolution
of 0.1 (0o.2) covering FOV of 4  4 at the focus
lower energy threshold of 20 GeV
Sensitivity : 5 Crab in 13 minutes > 200 GeV
43 minutes > 55 GeV
located near HAGAR : common events
first light expected in 2011
Will be augmented by one more similar element
by 2013 to enable stereoscopic operations

50. Astrophysical Sciences Division
MACE Simulations
Preliminary Results
Nilay Bhatt
on behalf of
Simulation Team :
Abhas Mitra
Subir Bhattacharyya
Nilay Bhatt
Astrophysical Sciences Division
BARC, Mumbai
HIGRO Collaboration Meeting, 01 – 03 December 2010 50 50

51. Cosmic Ray SImulation for KASCADE
Important Input parameter:
Primary Spectral Index :
1.8
Atmosphere Model
US standard (planar)
Cerenkov Waveband
240 – 650 nm
Observation level
4217 m asl
Magnetic Field (Hanle)
Bx = T, Bz = T
No. of Scatters 10
Gamma
Proton
Electron
Alpha
Energies (GeV)
1 – 104
10 – 104
5 – 104
Scatter Rad.(m)
400
500
Viewcone Angle -- 4o 5o
# showers
~ 106
Zenith Angles
0o , 20o , 40o , 60o

52. Differential Rate & Energy threshold Estimate
19 GeV
4 NNP, 5 p.e.
40 GeV

53. Differential Rate & Energy Threshold Estimate
For Protons :
For Electrons:
For Alpha :
4 NNP, 5 p.e.

54. Differential Rate Estimate
( Effect of the single pixel threshold )
4 NNP, 5 p.e. 54

55. Total/Integral Event Rates
5 p.e.
Primary
Rates (Hz)
Gamma
11.86
Electron
37.13
Alpha
137.7
Proton
818.8
Total
1005.5

56. Thank you