Dedicated supernova detection by a network of neutral current spherical TPC detectors
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TESTS OF NEW PHYSICS IN RARE PROCESSES AND COSMIC RAYS (Elementary Particles and Fields: Experiment)
Dedicated Supernova Detection by a Network of Neutral Current Spherical TPC Detectors* J. D. Vergados1)** and Y. Giomataris2)*** Received November 23, 2005
Abstract—Supernova neutrinos can easily be detected by a spherical gaseous TPC detector measuring very low energy nuclear recoils. The expected rates are quite large for a neutron-rich target since the neutrino–nucleus neutral current interaction yields a coherent contribution of all neutrons. As a matter of fact, for a typical supernova at 10 kpc, about 1000 events are expected using a spherical detector of radius 4 m with Xe gas at a pressure of 10 atm. A worldwide network of several such simple, stable, and low-cost supernova detectors with a running time of a few centuries is quite feasible. PACS numbers : 95.85.Ry DOI: 10.1134/S1063778807010164
1. INTRODUCTION Neutrinos appear to be excellent probes for studying the deep sky. They travel large distances with the speed of light. They can pass through obstacles without getting distorted on their way and they are not affected by the presence of magnetic fields. Thus, with neutrinos, one can see much further than with light. With light, one cannot observe further than 50 Mpc (1 Mpc = 3.3 × 106 light years). Furthermore, the detection of neutrinos reveals information about the source and more specifically about the source interior. Without neutrinos, we would probably know nothing about the Sun’s interior. Thus, neutrinos offer a good hope for understanding the early stages of a supernova. In a typical supernova, an energy of about 1053 erg is released in the form of neutrinos [1, 2]. These neutrinos are emitted within an interval of about 10 s after the explosion and they travel to the Earth undistorted, except that, on their way to the Earth, they may oscillate into other flavors. The phenomenon of neutrino oscillations is by now established by the observation of atmospheric neutrino oscillations [3] interpreted as νµ → ντ oscillations, as well as νe disappearance in solar neutrinos [4]. These results have been recently confirmed by the KamLAND experiment [5], which exhibits evidence for reactor antineutrino disappearance. Thus, ∗
The text was submitted by the authors in English. RCNP, Osaka University, Ibaraki, Japan; Physics Department, University of Ioannina, Ioannina, Greece. 2) CEA, Saclay, DAPNIA, Gif-sur-Yvette, France. ** E-mail: [email protected] *** E-mail: [email protected] 1)
for traditional detectors relying on the charged current interactions, the precise event rate may depend critically on the specific properties of the neutrinos. The time integrated spectra in the case of charged current detectors, like the SNO experiment, depend on the neutrino oscillations [6]. This, of course, may turn into an advantage for the study of neutrino properties [7]. An additional problem is the fact that the charged current cross sections depend on the details of the structure of the nuclei involved. During the l
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