Pavicevic, Miodrag and Henning, Walter and Kubo, Toshiyuki and Bosch, Fritz and Uesaka, Tomohiro and Litvinov, Yuri and Amthauer, Georg and Pejovic, Vladan and Anicin, Ivan and Boev, Blazo and Cvetkovic, Vladica (2016) Geochemical Determination of the pp-Neutrino Flux with 205Tl-LOREX: A Progress Report. In: XXVII International Conference on Neutrino Physics and Astrophysics, 4-9 July 2016, London, UK.
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Abstract
Intensive research from the 1970's to 1990's towards geochemical detection of solar neutrinos using
205
Tl,
98
Mo
and
81
Br has left
205
Tl the only viable candidate. LOREX (LORandite EXperiment
) is based on determining the solar
(pp) neutrino flux for the period of 4.3 Ma from the reaction
205
Tl+v
e
→
205
Pb+e
-
,
the lowest threshold (52 keV) for
neutrino capture. The ratio of
205
Pb/
205
Tl in lorandite (TlAsS
2
) depends also on contributions from
fast muon cosmic
radiation. The latter is a function of paleo
-
depth, including the eroded layer over 4.3 Ma, determined using
cosmogenic nuclides (
26
Al,
36
Cl,
3
He and
21
Ne) in the ore body Crven Dol (Tl
-
As
-
Sb
-
S) in Allchar (Macedonia). The
results give a l
ower limit of paleo
-
depth of 490mwe and an upper limit of 2300mwe. From this the ratios
205
Pb
ve
/
205
Pb
tot
are estimated as 2:8 and 6:4, respectively.
Identification
of the
205
Pb nuclei in the lead sample extracted from the lorandite mineral requires 10
-
10
to 10
-
11
overall detection sensitivity for
205
Pb/Pb and comparable suppression of the
205
Tl isobar. This is proposed by full
stripping of
205
Pb at high energy (345MeV/u) at the RIKEN
-
RIBF ion
-
beam facility.
205
Tl isobar separation is already
largely achiev
ed by chemical Pb
-
Tl separation by the overall sample preparation. Samples with a higher
concentration (
205
Tl/natPb=1%)
are necessary
for a guide
-
beam and initial accelerator tuning. A sample with a
considerably lower level of about 10
-
8
is needed for cont
rol of the beam analysis system with
205
Tl ions,
in the
presence ultimately of a lighter guide beam, to limit the
in
-
beam production of
205
Pb by the (p,n) reaction on
205
Tl in
the energy
-
loss and ion
-
stripping steps in the accelerator and the subsequent Bi
gRIPS/Mass
-
Ring experimental
apparatus. The relative cross sections between full stripping of
205
Pb and (p,n) on
205
Tl is estimated as 10
5
. Test
experiments to verify the various aspects of the proposed approach at the RIBF are under preparation.
| Item Type: | Conference or Workshop Item (Poster) |
|---|---|
| Subjects: | Natural sciences > Earth and related environmental sciences Natural sciences > Physical sciences |
| Divisions: | Faculty of Natural and Technical Sciences |
| Depositing User: | Biljana Kosturanova |
| Date Deposited: | 12 Jul 2016 08:27 |
| Last Modified: | 12 Jul 2016 08:27 |
| URI: | https://eprints.ugd.edu.mk/id/eprint/16048 |
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