Hyderabad :
A giant major atmospheric Cherenkov experiment (MACE) gamma ray telescope which weighs approximately 180 tones designed, developed and manufactured by Electronics Corporation of India Limited (ECIL), Hyderabad for Bhabha Atomic Research Centre (BARC), Mumbai has undergone all field trials successfully and is ready for getting dispatched to Hanle site in Ladakh region of Jammu and Kashmir.
When installed, this MACE Telescope will be the second largest gamma ray telescope in the world and will help the scientific community of the country to enhance its understanding in the fields of astrophysics, fundamental physics, and particle acceleration mechanisms.
Similar telescopes set up in Namibia, Europe and US have been realized by collaborative efforts of multiple institutions, whereas, the present MACE telescope has been designed and realized from concept stage to trial assembly stage by ECIL, Hyderabad with technology support from BARC, ECIL informed on Tuesday.
A flagging-off function of the MACE telescope by Dr. R.K. Sinha, Secretary, Department of Atomic Energy & Chairman, Atomic Energy Commission on June 28 at the Antenna Systems Group, ECIL.
ECIL scientists explained about the Major Atmospheric Cherenkov Experiment (MACE) Telescope. Very High Energy (VHE) gamma rays offer a unique insight into some of the most extreme phenomena of our Universe. Detection of celestial VHE gamma rays allows us to study 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.
When a VHE gamma ray photon enters the Earth’s atmosphere, it generates a shower of secondary charged particles which in turn cause a flash of blue Cherenkov light which lasts for only a few billionths of a second. 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 of magnitude more 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 21m diameter MACE Telescope being set up at Hanle (32.80 N, 78.90 E, 4200 m above MSL) in the Ladakh region of North India, will be the second largest gamma ray telescope in the world. The largest telescope of the same class is the 28 m diameter HESS telescope operating in Namibia. When fully operational by early 2016 it will enhance our understanding in the fields of Astrophysics, Fundamental Physics, Particle acceleration mechanisms for gamma-ray generation and Spectral cut off of Pulsars, ECIL said.
The MACE Telescope consists of a large area tessellated light collector of 356 sq mt, made up of 356 indigenously manufactured mirror panels. A 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 elevation over azimuth mounted telescope basket structure has two axes movement capability of ± 270o in azimuth and -26o to +165o 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 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 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 prime responsibility of Detailed Design, Manufacturing, Installation and Commissioning of the telescope has been entrusted by Bhabha Atomic Research Centre to ECIL who has done pioneering work in the field of Large Structures like the 32m IDSN Antenna for country’s 1st Lunar Mission Chandrayaan-1. More than 25 engineers are involved from ECIL in realizing the telescope over a period of four years. Astrophysical Sciences Division, Centre for Design and Manufacture, Electronics Division, Reactor Control Division and Reactor Safety Division of BARC have made major contributions to the development of various subsystems of the MACE telescope. Indian Institute of Astrophysics, Bangalore and Tata Institute of Fundamental Research, Mumbai are also associated with the project.
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 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.
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.
Earlier, similar telescopes of such huge size have been realized by consortium effort of developed nations from Europe & USA. However MACE telescope has been designed and realized from concept to commissioning with indigenous technology by ECIL with the support of BARC. Major Private Firms also have also contributed immensely to realize sub-systems like Wheel & Track Assembly, Gear Box Assembly, EL Bull Gear, EL Plummer block etc. Once the MACE system is operational, India will find its place in the elite scientific community working in field of Gamma Ray Study.
source: http://www.timesofindia.indiatimes.com / The Times of India / Home> City> Hyderabad / Ch. Sushil Rao, TNN / June 24th, 2014