1. “Major Atmospheric Cherenkov Experiment”
MACE Telescope
V K Dhar
Bhabha Atomic Research Centre, Mumbai
(On behalf of HiGRO collaboration)

2. MACE Gamma-Ray telescope
Atmospheric Imaging Cherekov telescope
MACE ( Major Atmospheric Cherenkov Experiment )
installed at Hanle (Ladakh)
Collaborators BARC, TIFR & IIA
Guidance regarding measurements with TS RRCAT
Industry Partner ECIL
Collaborating Divisions from BARC
MACE Gamma-Ray telescope
Architecture & Civil Engineering Division,
Atomic & Molecular Physics Division,
Centre for Design & Manufacture,
Computer Division, Control Instrumentation Division,
Division of Remote Handling and Robotics, Electronics Division,
Reactor Control Division, Reactor Safety Division,
Technical Services Division.
Aim : Study the universe in the energy range Eγ > 20 GeV (VHE domain)

3. Very High Energy (VHE) Gamma-rays
Energy Range : 20 GeV- 30 TeV
Constitute a viable discipline in its own right: TeV Gamma-ray Astronomy
A most recent window of electromagnetic spectrum to be explored in Astrophysics
OPTICAL

4. Universe Optical view
Universe seen from eye
so calm n peaceful…..
Gamma-ray view
Gamma ray sky shows us the most
exotic and extreme creatures in the
cosmic zoo.

5. Supernova Remnants (Vela Region)
Why study Gamma Rays—what different
Exploding stars (Supernova 1987A in Large Magellanic Cloud
HST/WFPC2 )
At the end of a star’s life, if it is large enough, it will end with a BANG.. (not a whimper!)
Supernova Remnants (Vela Region)
Radioactive decay of chem. elements created by Supernova explosion
Pulsars
Stellar corpses - size of a city, mass of the Sun BUT spinning up to 1000 times per second….

6. Gamma-ray Bursts (once a day…somewhere in universe)
Discovered in 1967 while looking for nuclear
test explosions
Burst ..or the death of life on Earth?
Hypernova
The end of life of a star (100 times the mass of our Sun), collapses to form rotating black holes (emitting twin energetic jets)
Conclusive evidence for this hypernova-GRB connection was obtained recently (SN1998bw)
Catastrophic Mergers
Death spiral of 2 neutron stars or black holes
Monstrous black holes
At the heart of every galaxy lies a black hole, millions to billions times mass of Sun

7. VHE Gamma-ray Sky & Science objectives
~VHE catalog :250 sources

8. 100 yr old puzzle- The origin of cosmic rays
 Cosmic particle accelerators imaged
using (secondary) gamma rays

9. Study of the dark sources ?

10. Not all remain dark: HESS J1813-178 promoted from unidentified source to SNR / PWN
TeV
size
S. Funk et al., astro-ph/
XMM
Radio
Supernova shell
D.J. Helfand et al.,
astro-ph/
… Huge potential for sensitive telescopes like MACE..

11. The technique

12. “Imaging” Atmospheric Cherenkov technique
Cherenkov pulse width ~5 ns
Large collection area ~ 105 m2
Effective gamma/hadron separation
CHALLENGES
Segregation γ/p
Energy
Arrival direction
Figure from Knapp’s
slides (TeVPA 2012)

13. Indian Gamma Ray Telescopes
TACTIC Gamma ray telescope
HAGAR array
Gulmarg Gamma ray telescope (BARC)
Pachmari array (TIFR)
HAGAR
Gulmarg
Pachmari
TACTIC
PAST
1st IMAGING telescope in Asia setup by BARC US, GERMANY, Australia/Japan had imaging telescopes. Operational since 1998, first ever detection of Mrk 501 along with Whipple, Hegra and CANGAROO telescopes.

14. The TACTIC telescope Features: Located at Mt Abu, India
Latitude :24.5 N
Longitude :72.7 E,
Altitude :1300 m (asl)
Operational since 1998
Light collector : 3.5 m (diameter)‏
Focal Length : 4.0 m
(34 front face Al-coated glass mirrors)‏
# Camera FoV : 5.9d x 5.9d
(349 pixels)‏
# Trigger FoV : 3.4d x 3.4d
# Trigger Criteria : 3NCT, NNP
# SPE threshold : 14pe
# Energy threshold : ~870 GeV
# Drive Control : SM based
(120Ncm)‏
# NIM & CAMAC

16. Himalayan Gamma Ray Observatory (HiGRO)
Collaboration of BARC, TIFR and IIA
Manufacturing & installation done by ECIL
2-m Himalayan Chandra Telescope
HAGAR 7 elements wave-front sampling array is operational
Stereo MACE (Major Atmospheric Cherenkov Experiment)
Installation of MACE is in advance stage (commissioning end of 2019),

17. Observatory site Hanle (J&K) (32.7d N, 79d E, 4200m asl)
Site Characteristics
Lat. And Long
N, E
Altitude
m asl
Nearest town
Leh (~260 Km)
Med. Temp.
-20 C (at night)
Min. Temp
-240 C (at night)
Med. Rel. Humidity
30%
Med. Wind speed
10 kmph
MACE Telescope site
Site specific Challenges
HAGAR (1/7)
2m HCT
High altitude related difficulties
Limited time for out-door work
Road transportation of equipment
Leh-Hanle travel time (~7 hr)
Low temperature
Power shortage
HANLE - Advantage of extending the longitudinal coverage of IACTS

18. Key features of MACE
Second largest (dia=21m, A=356m2) gamma-ray telescope in the
Northern hemisphere at Hanle, 4270m asl.
Lowest energy threshold ( ~20 GeV) in the northern hemisphere.
100% indigenous efforts.

19. No. of spectroscopic nights ~ 260/yr (few clouds)
Hanle
No. of spectroscopic nights ~ 260/yr (few clouds)
No. of photometric nights ~190/yr (no clouds)
Hanle (32046’46’’N, 78058’35’’E, 4270m asl)
Unique advantage
of altitude
Higher Cherenkov photon density
and large light collector results
in lowering the energy threshold
~20 GeV
Special targets for MACE
Pulsars and distant AGN

20. MACE Sub-systems Installed and tested MACE Telescope Camera
Electronics
Weather Station
Sky Monitoring
System
LED Calibration
System
Mirror Alignment
System
Control Room
Time Serve
Telescope Control
Unit
MACE console
Data Archive
System
Mechanical Structure, Sky Monitoring system, Mirror Alignment system, Telescope Control
Unit, Weather Station, LED Calibration system, Console software, Data Archive System
Installed and tested

21. Mechanical Assembly… completed
27 m diameter track
6 wheels
Bull gear
Central trusses
Adelade structure
Stiffening ring
Mirror basket
Quadruple booms
Camera housing

22. Light Collector of MACE
Number
Reflector Geometry
Parabolic Segmented
Mirror Profile
Spherical Facets
Surface Accuracy
DT ; Reflecting surface of λ /4 quality
Facet Material
Al MgSi Al alloy
Spot Size
80 % of light in about 6mm circle (ROC)
Mirror Reflectivity
80 % or higher
Surface Finish
20nm RMS or better
Protection Coating (SiO2) nm
356 m2 collection area
21m diameter (11 zones)
1564 mirror (½ X ½ )m diamond turned metallic facets fabricated
A first for the country!

23. Diamond turning machine Assembled panel alignment (1mX1m)
% Reflectivity
Test setup
Wavelength

24. MACE Camera Key features Camera Status
Detector : 1088-pixel PMT Camera
Camera Integrated Module (CIM) : 68
Dual gain channel
Fast data acquisition (~5 ns pulses are digitized)
1 GSPS, Domino Ring Sampler (DRS)
Pulse profile – 31 ns
High event rates – 1 kHz
Camera : temperature controlled
Camera Status
68 CIMs have been fully tested.
64 are installed in MACE Camera.
Console and all subsystem software functionally tested.
Remote operation of MACE Camera tested from BARC, Mumbai.

25. Camera Component Details
Camera Frame
CPC
2 m
2 m

26. Simulation study of MACE

27. MACE Data Analysis
Up to 500 GB data will be recorded per night 27

28. Validates the MACE instrumentation and analysis chain
Analysis of test run data
50 m2 mirror area, 64 CIMs without light concentrators
Signature of Cherenkov images
Validates the MACE instrumentation and analysis chain

29. Summary All the sub-systems of the telescope are installed.
Light collector 356 m2 installed.
Camera: Test runs conducted with 64 CIMs.
Simulation study up to 400 zenith angle completed.
Development of Data Analysis Software completed.
Commissioning of MACE by year end (2019).

30. Thank You ! MACE @ Hanle : Ladakh World class gamma-ray facility.
2nd largest in the world
Largest in the northern hemisphere.
All subsystems manufactured indigenously
Thank You !