Transcript of July 29, 2003; M.Chiba1 Study of salt neutrino detector for GZK neutrinos.
- Slide 1
- July 29, 2003; M.Chiba1 Study of salt neutrino detector for GZK
neutrinos
- Slide 2
- July 29, 2003; M.Chiba2 Generation of UHE neutrinos (>10 15
eV)
- Slide 3
- July 29, 2003; M.Chiba3 Astronomy in the highest energy region
1.Short interaction length 300Mpc to photons over 10TeV. 2.Protons
propagate less than 50Mpc due to Greisen, Zatsepin and Kuzmin (GZK)
cut off process over 10 20 eV. 3.Long-range astronomy, observing
old universe, in the highest energy region can be investigated by
neutrinos exclusively. 4.GZK cut off process generates UHE
neutrinos. p + (2.7K) + n + + p e - e + e + e 5. GZK neutrino is
probable to exist based on observed spectrum of UHE cosmic rays
with 2.7K cosmic microwave background.
- Slide 4
- July 29, 2003; M.Chiba4 Neutrino flux and optimal detector 1.It
is natural to aim at GZK neutrino at first. 2.Additions are direct
UHE neutrinos from AGN, GRB, Topological Defects, etc. 3.GZK
neutrino flux is as low as 1(km -2 day -1 ). 4.Large detector is
needed with information of energy, direction, time and flavor. For
the energy measurement, calorimetric detection is better than muon
track detection. 5.Radio wave detection is suitable way to realize
a large detector.
- Slide 5
- July 29, 2003; M.Chiba5 Coherent Cherenkov radiation in radio
wave region Askaryan in solid, 1961 M.Fujii and J. Nishimura in
air, 1969 Electron or photon beam Electrons are 20% excess over
positrons in an electromagnetic shower due to recoil electrons of
Compton scattering etc. 1.Cherenkov radiation: dP/d d P n
2.Coherent Cherenkov radiation: P n 2 2. Stronger radiation at UHE.
3.Radio transparent media should be used: rock salt, Lunar
regolith, Ice, etc. 4.Radio wave can be detected over 1TeV shower
near by and 1PeV shower 1km apart by a 300K-noise receiver without
absorption in the material. Rock Salt In Phase n excess
electrons
- Slide 6
- July 29, 2003; M.Chiba6 Observation of the Askaryan Effect
Askar effect is verified by high energy photon beam at SLAC.
M.Chiba
- Slide 7
- July 29, 2003; M.Chiba7 Properties of materials for UHE
Neutrino Detector Material Properties Air STP) Ice H 2 O ) Rock
salt (NaCl) Lime stone (CaCO 3 ) Density (g/cm 3 )
0.00120.9242.222.7 Radiation length X 0 (cm) 304203910.19.0
Refractive index n = 1.0002931.782.432.9 Cherenkov angle (deg)
1.38755.865.769.8 Cherenkov threshold energy(keV) , , 1075033 Rock
salt: high density, large refractive index and short radiation
length (a) Measurement of attenuation length L in situ ( P. Gorham
et al. ) (b) Measurement of complex permittivity at laboratory (
our work ) Synthesized NaCl : ' = 5.9, tan = 4.3 10 -5 L = 1080m at
1GHz.
- Slide 8
- July 29, 2003; M.Chiba8 World rock salt resources SALT DOMES,
Gulf Region, United States & Mexico, MICHEL T. HALBOUTY, Gulf
Publishing Company, Book Division, Houston, London, Paris, Tokyo,
1979 Handbook of World Salt Resources, Stanley J. Lefond, PLENUM
PRESS, NEWYORK, 1969 M.Chiba
- Slide 9
- July 29, 2003; M.Chiba9 3km 10km 1.Rock salt is free from
liquid and gas permeation petroleum or natural gas are likely to
deposit around the salt dome. 2.Free from water permeation results
good radio wave transparency. 3.Covered soil prevents surface radio
wave to penetrate. 4.Penetrating cosmic rays underground are too
spatially disperse to generate coherent Cherenkov radiation
effectively. Salt neutrino detector installed in a salt dome SND
Dow Earth Sciences, Geol: J.Hertzing
- Slide 10
- July 29, 2003; M.Chiba10 Underground Salt Neutrino Detector.
Moderate number of radio wave sensors could detect the neutrino
interaction in the massive rock salt. If the attenuation length L
=1km, 216 antennas are set at 400m intervals in 36 bore holes. It
works as an imaging calorimetric detector. Hockley salt mine, Texas
Array of the antennas 0m 2000m M.Chiba
- Slide 11
- July 29, 2003; M.Chiba11 Requirements for the antennas
- Slide 12
- July 29, 2003; M.Chiba12 Measurements of complex permittivity
of rock salts and lime stones Cavity perturbation method Absorption
depends on the surface condition of the samples, e.g. smoothness,
stain etc. 9.4GHz TE107 Q=4000 Size: 23x10x155mm 3 1GHz TM010
Q=10000 Size: 230mm x 30mm
- Slide 13
- July 29, 2003; M.Chiba13 Samples measured around 10GHz Rock
salt is fragile, so that it is not easy to make small stick samples
( 1mm x 1mm x 10.2mm ). Lime stone (especially Jura lime stone ) is
rigid. The small stick samples are obtained using a milling
machine.
- Slide 14
- July 29, 2003; M.Chiba14 Measurements of the suitability of
large rock salt formations Similar studies are done about UHE
neutrino detector utilizing rock salt. The results are consistent
with ours. M.Chiba
- Slide 15
- July 29, 2003; M.Chiba15 Dielectric resonator Attenuation
length M.Chiba
- Slide 16
- July 29, 2003; M.Chiba16 GZK neutrino detection
- Slide 17
- July 29, 2003; M.Chiba17 Conclusions 1.The attenuation length
of various rock salts and lime stones are measured at 1-12GHz by
the cavity perturbation method with 10 times better precision than
previous measurements at 10MHz and 25GHz. 2.Synthesized NaCl shows
' = 5.9, tan = 4.3 10 -5, L = 1080m at 1GHz. The tan is 5 times
smaller than the upper limit measured before at 10MHz. 3.The
attenuation length of rock salts in Hockley mine, Texas is tan =
2.3 10 -4, L = 180m at 1GHz. If the tan is constant with respect to
the frequency, L becomes 900m at 200MHz. L is long enough for the
salt neutrino detector. 4.We expect to detect 10 GZK neutrinos/year
by the salt neutrino detector with the volume of 2kmx2kmx2km.