The INO project BARC-CU-DU-HRI-Hawaii-HPU-IITB-IMSC-IOP-PU-PRL-SINP-SMIT-TIFR-VECC A brief introduction to neutrinos Schematic of the tracking Resistive Plate Chamber (RPC) Neutrinos were proposed by Pauli to save the laws of conservation of energy and angular momentum and statistics in nuclear beta decay. It has zero electric charge, mass 0 and exists, as far as we know, in 3 varieties viz. e corresponding to the electron and its heavier cousins the muon and tau lepton. Neutrinos interact only weakly with matter making them very hard to detect. For example, a 1 Me. V e has a mean free path in matter of about 108 km. Each neutrino has, if it is a Dirac particle, its antiparticle partner. However it could also be its own antiparticle (Majorana particle). If so one should observe neutrinoless double beta decay. Some pictures of the test setup Two 2 mm thick float Glass Separated by 2 mm spacer 2 mm thick spacer Pickup strips Sources of neutrinos Ø Atmospheric neutrinos - cosmic ray interaction in upper atmosphere produce and whose decay generates roughly two for every e, E Ge. V, neutrino flux ( e ) 105 m 2 sec 1 Ø Solar neutrinos - E 0. 1 -15 Me. V, ( e ) 6 1014 m 2 sec 1 Ø Neutrinos from man made sources such as nuclear power reactors - E 0. 1 -5 Me. V, ( e ) Ø Geoneutrinos – from beta decays of 40 K, 1013 m 2 sec 1 GWth 1 at Glass plates 1 km U and Th chains (contributing 40% heat production in earth) E 0. 1 -2 Me. V, ( e ) Graphite coating on the outer surfaces of glass Complete RPC 5 1010 m 2 sec 1 Efficiency and timing of glass RPC How does the RPC work Ø Supernova explosions in the cosmos where 99% energy released as neutrinos (total no. of neutrinos emitted over few secs 1058 Graphite Glass Plates Spacers 8 KV Signal pickup (y) Neutrino physics has witnessed an explosive growth following some landmark experiments : 1. Super. Kamioka - anomalous ratio of / e for atmospheric neutrinos and solar e deficit confirming the results of the pioneering 37 Cl experiment of Davis (fetching him the 2002 Nobel prize in Physics) 2. Sudbury Neutrino Observatory (deficit of solar e observed as other active species through the neutral current interactions) Graphite A passing charged particle induces an avalanche, which develops into a spark. The discharge is quenched when all of the locally available charge in an area 0. 1 cm 2 is consumed. Before 3. CHOOZ (no deficit of reactor anti- e over L 1 km) & Kam. Land (deficit of reactor anti- e over L 200 km) After ++++++++++ ------------- Atmospheric neutrinos were first detected in KGF (1965) by a TIFR group. The Indian Neutrino Observatory (INO) is an initiative to revive underground experiments in this exciting field (see http: //www. imsc. res. in/~ino). An Mo. U signed by participating DAE institutes on 30 th August, 2002 to work towards a proposal for INO. ++++++ ------- The discharged area recharges slowly through the high-resistivity glass plates. RPC gas mixture Freon 134 a : 62% Argon : 30% Isobutane : 8% All the above results with RPC in streamer mode. For higher count rate capability and longetivity it could be operated in the avalanche mode (lower HV, amplification needed, better timing After discussing various possibilities it was decided to work towards a 50 -100 k. T magnetized iron calorimeter (ICAL) with tracking gas detectors for measuring the momenta of charged products following neutrino interaction with the detector material. The physics goals of such a detector are: Schematic of 50 k. T magnetized iron calorimeter with tracking detector trays Ø The favored explanation of the results of neutrino Because of the small neutrino event rates experiments is that the neutrino flavour and mass cosmic ray muons are the most important source eigenstates are not the same, that at least two of background. This can be reduced to Ø++++++++++++++++++++++++++++++++++++Precisethat species have non-zero, but small masses and determination of manageable levels by locating the neutrino oscillation parameters using atmospheric neutrinos matter effects cause resonant transformations of detector deep underground (depth 1 km) in neutrino flavours (MSW effect) Ø Matter effect for neutrinos and antineutrinos, observed via R(L/E) = [N( )-N( )]/[N( )+N( )] for sin 2 2 13 0. 05 mines or tunnels Neutrino Oscillations (2 flavors) Ø Possible CP and CPT violation in leptonic sector (also if sin 2 2 13 0. 05) Ø Study of Kolar events, ultra high energy neutrinos and multimuon events flavor (e, ) & mass eigenstates (1, 2) Neutrino could be different, in general Ø In future ICAL could be used as the end detector in a long baseline accelerator neutrino experiment for determining oscillation parameters at a higher precision. The geographical location at a latitude of 11. 5 N allows the possibility of probing the earth’s core using accelerator neutrinos from Fermilab, USA In a weak process flavor eigenstates are produced which propagate in time as A possible configuration of current coils and magnetic field lines and direction Cosmic muon flux versus depth Schematic of atmospheric neutrino transport through earth to detector Disappearance of through Of the two possible sites, Rammam near Darjeeling in West Bengal and Pushep near Ooty in Tamilnadu, the latter has been chosen as the preferred site on the basis of seismicity, proximity to industrial towns, equator, connectivity etc. Schematic of underground experimental cavern Nup( ) / N Dm 2 L/E) sin 1 - sin 2 (2 Q) sin 2 (1. 27 down( ) vs-L/E 2 (2 Q) sin 2 (1. 27 Dm 2 L/E) (a simulation for ICAL) Detector Size of cavern : 150 m 22 m 30 m Earth Site & infrastructure detailed project report by March, 2007 Active collaboration from HEP and NP community is requested ! Panoramic view of Pushep site from TNEB guest house at Masinagudi
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