India-based Neutrino Observatory

Hunting the elusive


The India-based Neutrino Observatory (INO) project is an ambitious basic science project aimed at studying the properties and interactions of the elusive elementary particle called neutrino. The Government approved the INO project in January 2015. This included the construction of an underground laboratory at Bodi West Hills (BWH) in Theni district, Tamil Nadu, setting up the flagship Iron Calorimeter (ICAL) detector there and the Inter-Institutional Centre for High Energy Physics (IICHEP) in Madurai. IICHEP would be the nodal centre for Research & Development of the associated detector technology and would run the underground laboratory in Theni.

The key advantage of constructing a laboratory in a cavern in a mountain accessed by a 2km tunnel, with an all-round rock cover of about 1000m, is that it offers a low cosmic ray background environment (since the cosmic rays, and secondary particles produced in their interaction with the upper atmosphere, are filtered by the rock cover above the laboratory cavern). This is necessary for specialised experiments making measurements with neutrinos which interact very rarely with the detector material. In particular, ICAL will detect and measure atmospheric neutrinos to study the neutrino properties, including the mass ordering of the three tiny neutrino masses using matter enhanced neutrino oscillations. The ICAL detector can also be used to search for evidence of long-range interactions between neutrinos and matter, dark matter annihilation occurring in the sun, primordial magnetic monopoles and evidence for or against the anomalous events found by the proton decay detector in Kolar Gold Fields. Finally, the underground laboratory will also provide a conducive environment for other experiments. For example, a collaboration led by a TIFR group is working towards search for neutrinoless double beta decay in tin-124 using a cryogenic bolometer. Similarly, a collaboration led by SINP is planning to set up an experiment to search for Dark Matter using a cryogenic scintillator. The initial background studies have been initiated in a laboratory at -550m level in the Jaduguda mines.

Ph.D. programme for Human Resource Development

In 2008 the INO graduate training programme affiliated to the Homi Bhabha National Institute, a deemed to be University, was started. Between 3-8 students are selected and undergo one year of coursework with equal emphasis on experimental projects. About 20 students have passed out and have generally got good post-doctoral positions in India and abroad and some have also got faculty positions in institutes and University Departments. Furthermore, many students from INO collaborating institutes and universities also work towards their Ph.D. based on INO research problems. Detector development at IICHEP is expected to provide well-trained human resources not only for INO but also for other experimental projects in India.

Technologies Developed

Extruded polycarbonate side spacers and spacer buttons for RPCs; 1m1m, 2m2m Glass Resistive Plate Chambers with resistive graphite coating; front-end electronics; in-house developed boards for Data Acquisition, Trigger Module and Time Calibration.

High-permeability low-carbon soft iron steel for ICAL; Layered Electro-Magnet (85 ton mini-ICAL module); induction heating based copper joint brazing technology; inductive proximity sensor based system for continuous gap measurement between two iron plate layers; magnetic measurements system with multiple search coil pickup loops (for magnetic flux) and arrays of Hall probes based measurements (for B-field strength in inter-plate gaps); closed loop chilled water system for cooling current carrying coils in mini-ICAL and associated DC power supply; RPC trolley (8m high) to place and remove 2m2m RPC from ICAL.

Indian Collaborating Institutes

  • Aligarh Muslim University (AMU), Aligarh

  • American College (AC), Madurai

  • Banaras Hindu University (BHU), Varanasi

  • Bhabha Atomic Research Centre (BARC), Mumbai

  • Central University of Karnataka (CUK), Gulbarga

  • Delhi University (DU), Delhi

  • Harish Chandra Research Institute (HRI), Allahabad

  • Indian Institute of Science Education and Research (IISERM), Mohali

  • Indian Institute of Technology Bombay (IITB), Mumbai

  • Indian Institute of Technology Gandhinagar (IITG), Gandhinagar

  • Indian Institute of Technology Madras (IITM), Chennai

  • Institute of Physics (IOP), Bhubaneswar

  • Institute of Mathematical Sciences (IMSc), Chennai

  • Jammu University (JU), Jammu

  • Jawaharlal Nehru University (JNU), New Delhi

  • Lucknow University (LU), Lucknow

  • Panjab University (PU), Chandigarh

  • Physical Research Laboratory (PRL), Ahmedabad

  • Saha Institute of Nuclear Physics (SINP), Kolkata

  • Tata Institute of Fundamental Research (TIFR), Mumbai

  • Tezpur University (TU), Tezpur

  • University of Calcutta (UCK), Kolkata

  • University of Calicut (UCC), Calicut

  • University of Hyderabad (UoH), Hyderabad

  • University of Kashmir (UK), Srinagar

  • University of Mysore (UM), Mysore

  • Utkal University (UU), Bhubaneswar

  • Variable Energy Cyclotron Centre (VECC), Kolkata

Indian Industry Partners


  • Tata Consulting Engineers, Mumbai (ICAL magnet DPR)

  • Tamil Nadu Electricity Board, Chennai (INO DPR)

  • Mitcon Consultancy & Engineering Services Ltd, Pune (MoEF&CC clearance)

  • Pro Designa Consultants, Madurai (Civil works approval for IICHEP, INO site civil construction)

  • Walchand Technology Group, Pune (Project Report for RPC manufacture)

RPC glass gaps

  • St. Gobain (Sriperumbudur)

  • Asahi-India (Taloja)

  • Cybernetic Instruments (Pune)

Closed loop gas system

  • Alpha Pneumatics (Mumbai)

  • Shriram Automation (Mumbai)

Resistive coating of graphite paint on glass

  • Kansai-Nerolac (Mumbai)

RPC trays and pickup panels

  • Honeycomb International Inc. (Bengaluru)

  • Nexgen Plastics (Mumbai)

  • S. M. Enterprises (Pune)

  • Fibre Reinforced Industry Ltd (Pune)

Polycarbonate spacers for glass gaps

  • Ashwin Plastics (Mumbai)

  • Studio CNC (Mumbai)

Low carbon magnetic grade steel plates

  • Steel Authority of India Ltd. (Bhilai)

  • Essar Steel (Hazira)

Electronics boards of many types

  • Rangsons (Bengaluru)

  • Dexcel (Bengaluru)

  • PCBPower Circuit Systems India Ltd (Gandhinagar)

RPC handling equipment, mini-ICAL assembly

  • Jalaram Industries (Mumbai)

  • P Chandru Machine Tools (Vellore)

  • Green & Green Engineering Solution (Coimbatore)

Magnet Power Reversal switch and gap measurement system

  • M/S Integrated systems Pvt. Ltd (Mumbai)

Magnet coil support G-10 material

  • Autoelectrical & Mechanical works (Mumbai)

Soft iron plate and SS Spacer-Pin machining

  • Bhilai Engineering Corporation (Bhilai)

Special Induction based brazing machine

  • Microtech Industries (Mumbai)

Low conductivity cooling water system

  • Entech industries (Banglore)

Magnetic Measurement Systems

  • Ferrite India (Pune)


1. Where is the INO site?

The proposed underground site for the INO lab is located in the Bodi West Hills region, about 2 km from the nearest village Pudukottai in Pottipuram Panchayat, Theni District of Tamil Nadu. The nearest major city is Madurai, about 110 km away. It is also the nearest airport and a major railway station. A cavern will be created to house the lab about 1200 metres deep below a mountain top. The cavern will be accessible by a 2100 m long and 7.5 m wide tunnel.

2. What is the status of the project?

Presently, pre-project works for the INO mega project are underway. Among current notable achievements, a small-scale 80 ton ‘prototype’ ICAL detector has been developed indigenously and set up at the project’s facility in Vadapalanji near Madurai.

3. How will the INO lab detect neutrinos?

The underground INO lab will have a 50,000 ton Iron-Calorimeter (ICAL) Detector for detecting and studying neutrinos. The detector consists of magnetised iron plates arranged in stakes, with gaps in between the plates. Glass-based Resistive Plate Chambers (RPCs) will be inserted as inside these gaps to act as active detectors. Charged particles produced in the rare interactions of neutrinos with the iron would be detected in these detectors.

4. Why is the INO lab to be set up underground?

Neutrinos arise from various cosmic nuclear processes. They have almost zero mass and they travel nearly at the speed of light. Neutrinos can easily pass right through earth and other celestial bodies like the sun, and since they are neutral (no charge), they are not affected by electromagnetism. Thus, detecting neutrinos is difficult. The rock above the underground laboratory will serve as a filter to remove unwanted portion of cosmic rays, so that unambiguous and precise detection of neutrinos can be made

5. Will there be any radioactivity?

No. The main reason for locating the laboratory underground is to create an environment free of the radiation that abounds on the earth’s surface. This radiation is due to cosmic rays and natural radiation of the materials around us. Hence the experiment will neither produce any radioactivity nor can it function well where there is radiation.

6. Does the INO project offer other benefits?

The INO project is a mega science project that has several spin-off benefits. The initial goal of the INO is to study neutrinos using the ICAL detector, which is being developed entirely indigenously, along with several technologies associated with it. Over the years, this underground facility is expected to develop into a full-fledged underground science laboratory for other studies in physics, biology, geology, hydrology etc.

7. How is the INO project funded?

It is a mega-science project with an investment of about 1,538 crore, jointly funded by the Department of Atomic Energy (DAE) and the Department of Science and Technology (DST).

Connect with Us

Contact Person

Prof. V.M. Datar,
Project Director,
INO, TIFR, Mumbai-400005

Phone: 91-22-22782715

Email: |