Abstract
Three experiments were conducted with a volunteer to test the kinetics of the 222Rn exhalation after a shorttime exposure to an elevated 222Rn air concentration. Radon concentration in an ...exhaled air was measured, complemented by whole body counting of 222Rn decay products in a body. Exhaled activities are compared with the prediction of the recent ICRP biokinetic model for radon. While a rapid equilibration of the exhaled radon activity concentration with that in the air inhaled corresponded with the model, the measured 222Rn exhalation rate was significantly less than modelled. Five hours after termination of the inhalation phase, the radon concentration in the exhaled air decreased to levels expected for non-elevated indoor radon activity concentration. Whole body activities of the 222Rn decay products were found higher than expected. Inhalation of the unattached fraction or residual activity of decay products in the air inhaled may be the explanation.
Investigation of double beta decay processes (β+EC, EC/EC) of 58Ni was performed at the Modane underground laboratory (LSM, France, 4800 m w.e.). A sample of natural nickel, containing ∼68% of 58Ni ...and a mass of ∼21.7 kg, was measured using ultra low-background HPGe detector Obelix (sensitive volume of 600 cm3) during ∼143.8 days. New experimental limits on 2νβ+EC decay of 58Ni to the ground 0+ and (math), 811 keV excited state of 58Fe, and 2νEC/EC decay of 58Ni to (math), 811 keV and (maht), 1 675 keV excited states of 58Fe were obtained in this measurement. There are -T1/2(β+EC, 0+ → 0+) > 1.7 × 1022 y; (math), (math), (math). For resonant neutrino-less radiative EC/EC decay with energy of 1 918.3 keV a new experimental limit of T1/2 (0νEC/EC - res, 1918KeV) > 4.1 ×1022 y was also obtained. All limits are at 90 % CL.
Investigating the Double Beta Decay of 58Ni Rukhadze, N. I.; Brudanin, V. B.; Klimenko, A. A. ...
Bulletin of the Russian Academy of Sciences. Physics,
06/2018, Letnik:
82, Številka:
6
Journal Article
Recenzirano
Double beta decay (β +
EC
,
EC/EC
) of
58
Ni is investigated at France’s Modane Underground Laboratory (4800 m water equivalent) using the OBELIX ultralow-background HPGe detector with a sensitive ...volume of 600 cm
3
and a natural nickel sample of ~68% 58Ni with a mass of ~21.7 kg. After preliminary analysis of the experimental data accumulated over ~144 days, new experimental limits are obtained for the 2νβ
+
EC
decay of
58
Ni to the 0
+
ground state and the 2
1
+
, 811 keV excited state of
58
Fe, and for the 2ν
EC/EC
decay of
58
Ni to the 2
1
+
, 811 keV and 2
2
+
, 1675 keV excited states of
58
Fe. The limits are
T
1/2
(β
+
EC
,0→0
+
) > 1.7 × 10
22
yr,
T
1/2
(β
+
EC
,0→2
1
+
) > 2.3 × 10
22
yr,
T
1/2
(
EC/EC
,0→2
1
+
) > 3.3 × 10
22
yr, and
T
1/2
(
EC/EC
,0→2
2
+
) > 3.4 × 10
22
yr. Experimental limit T
1/2
(0ν
EC/EC
–res, 1918 keV > 4.1 × 10
22
yr is obtained for resonant neutrinoless radiative EC/EC decay with an energy of 1918.3 keV. All limits are at 90% CL.
Abstract
This paper presents the gamma-ray detection performance of the newly developed MAPD-3NM-II type SiPM sensor array (4
$$\times$$
×
4) with
$$\hbox {LaBr}_3$$
LaBr
3
(Ce) scintillator. The ...gamma-ray spectra of various sources have been measured in the energy range from 26 keV up to 1332 keV. The newly developed array based on MAPD-3NM-II sensors proved
$$\sim$$
∼
22% enhancement in energy resolution in comparison to the former MAPD-3NM-I based array. The energy resolution of 662 keV gamma-rays measured by MAPD-3NM-II was 3.3% while clearly surpassing 4.25% resolution of MAPD-3NM-I predecessor. The enhancement is related to the high PDE of the new MAPD-3NM-II. Obtained results show that the new MAPD-3NM-II demonstrated good energy resolution and linearity in the studied energy region. The energy resolution of the new detector developed based on MAPD-3NM-II was better than all previous products of MAPD.
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