A national project to study fundamental particles called neutrinos has suddenly been drawn into an unwarranted controversy by V. S. Achuthanandan, the former CPI (M) Chief Minister of Kerala and leader of the Opposition in the Kerala Assembly, in association with an environmental activist, V.T. Padmanabhan.
The project involves the construction of an underground laboratory, called the India-based Neutrino Observatory (INO), to be located in a cavern under a rocky mountain in the Bodi West Hills region of the Theni district, about 110 km west of Madurai in Tamil Nadu.
What are neutrinos? After photons, they are the most abundant particles in the universe. Among the known fundamental particles, they are also perhaps the strangest. They interact very feebly with other particles. Therefore, all forms of matter, including the earth, are nearly transparent to them. About 100 trillion neutrinos from the sun and other cosmic sources pass through our bodies every second without causing any harm.
Rare interaction
As they interact very rarely, they are not easily detected and, therefore, not well studied. The large background flux of other particles in the cosmic rays presents an additional complication in their detection. Neutrino detectors are, therefore, usually placed deep underground, typically a kilometre or deeper. The large overburden of rock or earth above the detectors reduces the background particles by a million times or more. While almost all neutrinos pass through freely, a few interact in the detectors and can be detected. Many neutrino detection experiments are on in different parts of the world and, with growing interest in neutrino physics, many others are being proposed and built. The INO is one such that has evinced worldwide interest.
It is now known that neutrinos come in three types (electron-neutrino, muon-neutrino and tau-neutrino). Once thought to be massless, they are now known to have very tiny masses. But their individual masses remain unknown. Of the three neutrino flavours, the heaviest has at least one 10 millionth the electron’s mass. Which flavour is the heaviest? The ordering of neutrino masses too is unknown. This is called the ‘mass hierarchy’ question, which the INO is well suited to investigate.
The strange particles also have the ability to morph from one type to another as they pass through space, people, matter and the Earth itself, rarely interacting with anything in their path. This is called neutrino oscillation. While the details of two oscillations are known fairly well, the third — the switching of tau-neutrino to electron-neutrino — is not well characterised and forms one of the main objectives of the INO.
The idea for a neutrino observatory in India was first mooted in 2000 at an international conference in Chennai. The proposal was further refined and consolidated at the 2001 Neutrino meeting in Chennai, when the INO consortium of collaborating Indian institutions was formed. In 2002, a formal proposal was submitted to the Department of Atomic Energy, which has since been the nodal agency for the project.
The project has now been identified as one of the mega science projects in the XII Plan with an investment of Rs. 1,350 crore by the DAE and the Department of Science and Technology (DST). At present, 26 Indian institutions — which include Calicut University — and about 100 scientists are involved, with the Tata Institute of Fundamental Research, Mumbai, as the nodal institute.
It is therefore bizarre that Mr. Achuthanandan and Mr. Padmanabhan should allege that the INO is a project of Fermilab, USA, initiated along with the controversial Indo-U.S. nuclear deal. It is a totally indigenous project, conceived jointly by scientists from many Indian research institutions and initiated long before negotiations for the Indo-U.S. nuclear deal began in 2005. Nor was Fermilab, USA, anywhere in the picture then. The project is a basic science experiment that has nothing to do with radioactivity or any other hazardous nuclear activity. Nor does it have any defence or strategic implications.
A site within the complex of the hydroelectric project PUSHEP of the Tamil Nadu Electricity Board at Singara, near Mudumalai Sanctuary in the Nilgiri Hills, was identified in 2002 as the best option for the project from the geological, environmental and infrastructure points of view. The TNEB prepared the detailed project report in 2007. But, after prolonged delays, the Tamil Nadu Forest Department rejected the proposal in 2010, despite the project being located entirely on the TNEB land.
The reason — the site fell in the buffer zone of the Mudumalai Tiger Reserve and the elephant corridor connecting the Eastern and the Western Ghats. Interestingly, the notification declaring the area as a tiger reserve was issued only in 2008, six years after the INO project was proposed and two years after the DAE applied to the Tamil Nadu Forest Department for approval. More pertinently, a report by Dr. R. Sukumar, an expert on the Nilgiris Biosphere Reserve from the Indian Institute of Science, Bangalore, had clearly stated that the project would not be detrimental to the wildlife and environment of the region. It may be pointed out that, at the same time, there is no serious effort to stop the ever-increasing tourist and vehicular traffic and mushrooming resorts in the region.
The location in Bodi West Hills was chosen as the next best site. The main INO laboratory will be located in a cavern 1.3 km below a mountain peak. There, an entirely indigenously built magnetised iron calorimeter detector, weighing about 50 kilotons, will be used to detect both natural and man-made neutrinos. The cavern will be linked to the outside world by a 1.9 km long main tunnel.
In Phase I, however, INO will study only neutrinos produced by cosmic rays in the Earth’s atmosphere. In Phase II, it could be used as a far detector for using beams from future accelerator-based ‘neutrino factories’ in Japan, Europe and the U.S. The INO is expected to become operational in 2017 when the first module of the detector will start taking data.
Contrary to Mr. Achuthanandan and Mr. Padmanabhan’s accusations of secrecy and lack of transparency, all the details about the project are available on its website www.ino.tifr.res.in. Among other issues they have raised is that, because of the project site’s proximity to the Tamil Nadu-Kerala border, permission from the Kerala government should have been sought. In their view, during the rock-blasting for construction, the project could seismically impact the Mullaperiyar dam that is about 100 km away. It is also alleged that neutrino beams from Fermilab would adversely affect the biodiversity of the region.
According to M.V.N. Murthy of the Institute of Mathematical Sciences, Chennai — another key institution involved in the project — a proper geotechnical analysis has indeed been done. The measures adopted to minimise the project’s environmental impact have been detailed in the Environmental Impact Assessment report and also briefly described in the FAQ, both of which are available on the INO website. This includes controlled blasting that will be adopted in the initial reaches to dampen noise and vibration. Even this is expected to last only for the initial few months when the first few hundred metres of the tunnel are built.
Minimal vibrations
Blasting for the excavation of the cavern and associated laboratory infrastructure is expected to cause only minimal vibrations. The INO, says the FAQ, will undertake ground vibration monitoring and other rock mechanics studies during the actual blasting. Appropriate blasting pattern and modern blasting techniques based on the actual site geology will be followed so that the vibration is minimised. But, more pertinently, there are hundreds of granite quarries in the Theni-Idukki region where constant rock blasting goes on throughout the year, which are not known to have had any impact on the dam.
As regards the INO possibly receiving neutrinos beamed from Fermilab, which may happen 10-15 years hence, that has to do with physics and not some ulterior U.S. strategic motive as is being imagined. Also, since neutrinos rarely interact with matter, just as the atmospheric neutrinos, these neutrinos too will pass through without disturbing anything along their path, in particular the biodiversity as is being apprehended.
As it is, the inability to proceed with the project at the original Nilgiris site has set back the project by at least six-seven years. Consequently, China has upstaged INO in one of its main science goals. Only in 2004 — two years after the INO proposal — did China propose an experiment to use neutrinos from a nuclear reactor at Daya Bay and a detector located in an underground tunnel under a nearby hill. That experiment started taking data last year and, in March 2012, measured a key unknown parameter relating to oscillation between tau-neutrino and electron-neutrino. This was subsequently verified in April by a similar Korean experiment, RENO, initiated in 2006. It also began operation last year.
The already much-delayed and important physics project can do without another needless controversy at this point of time.
