Worlds second largest gamma ray telescope in Ladakh

A giant Major Atmospheric Cherenkov Experiment (MACE) gamma ray telescope is being transported to Hanle, Ladakh from Hyderabad.

MACE had undergone all field trials successfully before it was dispatched to Ladakh.

It is developed and manufactured by Electronics Corporation of India Limited (ECIL), 

Hyderabad for Bhabha Atomic Research Centre (BARC). It weighs approximately 180 tones designed.

When installed, it will be the second largest MACE gamma ray telescope in the world at highest altitude Hanle, Ladakh. (World’s largest MACE gamma ray telescope is set up in Namibia. Europe and US by collaborative efforts of multiple institutions had built this telescope.)

It will help the scientific community of the country to enhance its understanding in the fields of astrophysics, fundamental physics, and particle acceleration mechanisms for gamma-ray generation and spectral cut off of Pulsars.

Assembling Schedule of telescope

The mechanical structure of the telescope will be shifted to Hanle by August 2014 and assembly work will start there by September 2014.

The circular track, wheel assemblies and the major portion of the supporting structure will be assembled at Hanle by November 2014.

The remaining assembly will be completed during the summer of 2015.

The Imaging Camera will be integrated to the telescope in October 2015 and the telescope will see first light in the form of gamma-ray emissions from the Crab Nebula, which is a standard calibration source in the Northern Hemisphere, in December 2015.

About Major Atmospheric Cherenkov Experiment (MACE) Telescope

• The MACE Telescope consists of a large area tessellated light collector of 356 sq mt, made up of 356 indigenously manufactured mirror panels.
• It has high resolution imaging camera weighing about 1200 kgs, for detection and characterization of the atmospheric Cherenkov events forms the focal plane instrumentation of the telescope. The telescope has an integrated imaging camera, which contains 1088 photo multiplier based pixels and all the signal processing and data acquisition electronics. The camera communicates the acquired data to the Computer system in the Control Room over optical fiber.
• The elevation over azimuth mounted telescope basket structure has two axes movement capability in elevation for pointing towards any source in the sky and tracking it.
• The telescope which weighs about 180 tons is supported on six wheels which move on a 27m diameter track.
• The main features of the telescope include safe and secure operation of the telescope remotely from anywhere in the world, and it's structure is designed to operate in winds of speed up to 30 kmph and retain its structural integrity in the parking position in winds of speed up to 150 kmph.
• The manufacturing of the structural elements of the telescope has been completed and the proof assembly of the mechanical structure along with the Drive Servo System has been completed at ECIL, Hyderabad to assess the functionality of the telescope.
• The telescope Control Room Building, Guest house, Battery storage building and the Solar Power Array with a battery bank to support two Sunless days has been set up at Hanle.

 Working of Major Atmospheric Cherenkov Experiment (MACE) Telescope

• The telescope is named after the Soviet scientist Pavel Cherenkov who predicted that charged particles moving at high speeds in a medium emit light.
• The Very High Energy (VHE) energy gamma rays emitted from black holes, centers of galaxies and pulsars do not reach the land as they get absorbed in the atmosphere.
• When VHE gamma rays interact with the atmosphere, the photons from interaction produce electron–positron pairs leading to a cascade of particles which while moving at very high speed give rise to Cerenkov radiation.
• VHE gamma rays offer a unique insight into some of the most extreme phenomena of our Universe. Detection of celestial VHE gamma rays allows the study of exotic objects like Pulsars, Pulsar Wind Nebulae, Super Nova Remnants, Micro quasars, Active Galactic Nuclei etc where particles are accelerated to TeV (1012eV) energies and beyond.
• These exceptionally energetic photons are detected on the Earth by an indirect process which uses the Earth's atmosphere as a transducer.
• The Cherenkov light is beamed around the direction of the incident gamma ray and covers an area of around 50,000 square meters on the ground.
• This Effective Area is far larger in magnitude than the area of satellite instruments used for detecting gamma rays directly.
• To detect these flashes of Cherenkov light, photomultiplier tube cameras are used at the focus of large tracking light collectors. The intensity of the image recorded by the telescope is related to the energy of the incident gamma ray photon.
• The telescope’s integrated imaging camera which has signal processing and data acquisition electronics to capture the data of flashes of Cherenkov light. The intensity of the image recorded by the telescope is related to the energy of the incident gamma ray photon.
• Then camera communicates the acquired data to the Computer system in the Control Room over optical fiber.