INDIA-BASED NEUTRINO OBSERVATORYINO Collaboration

About the Project

The existence of non-zero neutrino masses hasprofound implications on fields as varied as nu-clear physics, geophysics, astrophysics and cos-mology apart from being of fundamental inter-est to particle physics. The discovery of neu-trino mass and oscillation is but a first step andthere are several questions that may require dif-ferent experiments spanning many decades tobe resolved. We still do not know the scale ofneutrino mass, we only partly know the extentof mixing and not even sure if the neutrino isits own antiparticle or not. The experimentalfield of neutrino physics is now moving into aphase where decisive and high precision experi-ments are needed. It was in this context that aninitiative began to take shape a few years agoleading to the idea of the India-based NeutrinoObservatory (INO).

Location and Structure

The detector will be placed inside a mountain atTheni near Madurai in South India. The rockburden of over 1 km on all the directions shieldsthe detector from other cosmic rays. The geo-graphical location is particularly interesting, asall the existing neutrino detectors are at lati-tudes larger than 35 degrees N or S. There isnone close to the equator as yet.

Figure: INO site at West Bodi Hills near Theni.

Two caverns, one to house the detector and an-other to house the control systems will be builtinside the mountain. A 2km long tunnel willconnect these caverns to the portal outside themountain.

Figure: Schematic of detector caverns.

Detector

Considering the physics possibilities and given the past experienceof Indian scientists at the Kolar Gold Mines, it was decided to startwith a modern Iron Calorimeter (ICAL) detector with ResistivePlate Chambers (RPC) as active detector elements. This massivedetector (50 kton) has been designed to achieve a statisticallysignificant number of neutrino interactions in a reasonable timeframe with good energy and angular resolution to measure L/Ewith an accuracy better than half the modulation period. Themagnetic field in the detector gives the possibility of distinguishingbetween neutrino and anti-neutrino interactions.

Figure: The Iron Calorimeter.

Detector Parameters• 3 modules each of size 16m x 16m x 14.5m.• 150 layers of RPCs interleaved by Iron plates of thickness56mm.

• 64 (8 x8) RPCs per layer per module.•Total of 28,800 RPCs of size 1.84m x 1.84m x 24mm, with 64strips (30mm pitch) on either read-out planes.

•Magnetic field of 1.3 Tesla.•Total of 3.6 million electronic channels.

Industrial Interaction and Collaborations

ICAL is an engineering intensive experiment and therefore requiresstate-of-the-art engineering inputs and expertise to design, fabri-cate and assemble. INO group has already tied up with a numberof Indian industrial houses. Various jobs related to the prepara-tion of a Detailed Project Report for the detector, cavern and thesurface facilities are made by agencies having special expertise inthose fields. Industries are also involved in the development ofgas recirculation system, electrode paint and in the fabrication oflarge area RPCs. Other areas where we currently consulting localindustries are machining of ICAL’s iron plates, large scale produc-tion of RPCs, magnet design, large volume gas recycling systems,fabrication of high density VLSI circuit based modules etc.

ContactVisit us at www.ino.tifr.res.in or write to nkm@tifr.res.in to knowmore about this project.

Main Goals•Unambiguous and more precisedetermination of oscillation parametersusing atmospheric neutrinos.

•Study of matter effects through electriccharge identification, leading todetermination of sign of δm2

23.•Study of CP violation in the leptonicsector and possible CPT violation studies.

•Study of very-high energy neutrinos andmulti-muon events.

Graduate Training Program

A large number of well trained manpower isneeded to lead the experimental activities ofthis project. In order to achieve this goal, atraining program with strong emphasis on ex-perimental high energy physics was started inAugust 2008.

Outreach and Awareness

As part of its responsibility toward the soci-ety, the INO team regularly organizes aware-ness meetings and outreach programs. Studentsfrom schools and colleges are invited to the labsat TIFR and are introduced to concepts in de-tecting high energy particles. Outreach pro-grams to people near the site are conductedwith the help of the district and village admin-istrative bodies.

Other Experiments of INOThe INO project will also host other neu-trino experiments like the Neutrino-less dou-ble beta decay (NDBD). NDBD experimentswill reveal the nature of neutrinos (Majaronaor Dirac). This experiment will be placed inthe control room cavern. A crucial criterionfor detector design for this experiment is highenergy resolution for a precision measurementof the sum energy of two electrons emitted inthe decay. The low temperature bolometricdetectors are ideally suited for this purpose.The group focuses on the feasibility of a Sncryogenic bolometric detector using 124Sn.

Figure: The stack of 2mx2m RPCs at TIFR, Mumbai.