The main limitation in the high-sensitive HPGe gamma-ray spectrometry has been the detector background, even for detectors placed deep underground. Environmental radionuclides such as 40K and decay ...products in the 238U and 232Th chains have been identified as the most important radioactive contaminants of construction parts of HPGe gamma-ray spectrometers. Monte Carlo simulations have shown that the massive inner and outer lead shields have been the main contributors to the HPGe-detector background, followed by aluminum cryostat, copper cold finger, detector holder and the lead ring with FET. The Monte Carlo simulated cosmic-ray background gamma-ray spectrum has been by about three orders of magnitude lower than the experimental spectrum measured in the Modane underground laboratory (4800 m w.e.), underlying the importance of using radiopure materials for the construction of ultra-low-level HPGe gamma-ray spectrometers.
•Monte Carlo simulations of HPGe gamma-ray spectrometer background for Modane underground laboratory was carried out.•The GEANT4 software package was applied in simulations of background gamma-ray spectra.•The spectrometer background was mainly due to radioactive contamination of its construction parts.•Monte Carlo simulated background was by about three orders of magnitude lower than the experimental one.
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.
Searching for the β+EC and EC/EC Decays of 74Se Rukhadze, N. I.; Barabash, A. S.; Brudanin, V. B. ...
Bulletin of the Russian Academy of Sciences. Physics,
08/2020, Letnik:
84, Številka:
8
Journal Article
Recenzirano
Double beta decay (β
+
EC, EC/EC) of
74
Se was investigated at the Modane underground laboratory (LSM, France; 4800 m of water equivalent) using the OBELIX ultralow-background HPGe detector with a ...sensitive volume of 600 cm
3
and a sample of natural selenium with a mass of 1.6 kg containing ~0.89% (~14.24 g) of
74
Se. The new experimental limits for β
+
EC and EC/EC decays of
74
Se to ground 0
+
and excited
596 keV, and
1204 keV states of
74
Ge, were obtained from experimental data accumulated over 135 days.
The objective of the study was to analyze association of echocardiographic TOD variables with the CVD risk groups defined by WHO/ISH. A cross-sectional study was conducted between (September 2008 - ...December 2010) Consecutive sample of 146 participants were enrolled in the study, 97 (66.4 %) women and (49) 33,6 % men, mean age. Study population was categorized in three groups according to WHO/ISH risk categories: Group 1 included population with risk less than 10% according to WHO/ISH, in Group 2 there were united two WHO/ISH risk categories (10-10.9% and 20-29.9%) and Group 3 represented population of 30-39.9% and more than 40% of CVD risk. Routine Echocardiography was conducted. The data was analyzed using SPSS, version 21. The distribution of echocardiography characteristics in WHO/ISH groups was statistically different for LA, PSP and EF (P<0.05). In groups I and II LA were only mildly dilated, while in group III was revealed moderate LA enlargement. The mean PSP was in normal range in groups I and II and mildly to moderate elevated in group III. The mean EF was in normal range for all the groups with tendency of reduction from group I to group III. Unlike this we have not found statistically significant differences in other echocardiographic variables, as IVS, PWT, LVD and LVEDV and they were in normal range for all risk groups. According to the findings of our study and considering that our study population is without any clinical presentation of cardiovascular disease and still have statistically significant tendency toward increase in LA and PSP we argue that those variables can be considered as early predictors of cardiovascular disease. Furthermore, it is recommended to include echocardiographic examination as part of the CVD risk evaluation protocol in selected population.
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.
The objective the study was to assess the association between echocardiographic parameters and established cardiovascular risk factors in adults without clinical manifestation of heart failure (HF). ...A cross-sectional study was conducted between (September 2008 - December 2010) Consecutive sample of 177 participants were enrolled in the study. We performed routine Transthoracic Echocardiography and evaluated several well established cardiovascular risk factors. The data was analyzed using SPSS, version 16. LA was significantly correlated with age (r 0.396, p<0.000), WC (r 0.291, p<0.005), BMI (r 0.233, p<0.005), SBP (r 0.208, p<0.012) and TCH (r 0.163, p<0.049); IVS - with age (r 0.318, p<0.000), WC (r 0.259, p<0.002), BMI (r 0.178, p<0.032), TCH (r 0.191, p<0.022); PWT - with age (r 0 313, p<0.000), WC (r 0.270, p<0.001), BMI (r 0.204, p<0.013), TCH (r 0.168, p<0.042); LVD - WC (r 0.201, p<0.015) and BG (r 0.176, p<0.034); with LVEDV - WC (r 0.240, p<0.004); with EF - SBP (r- 0.202, p<0.015), DBP (r -0.171, p<0.015) and with PSP - age (r 0.286, p<0.000), SBP (r-0.243, p<0.003), DBP (r 0.254, p<0.002). As echocardiography characteristics are independent risk factors for Heart Failure development and progression and as most of them are correlated the age and obesity variables it should be appropriate to conduct routine echocardiography in aged and obese patients even in low CVD risk group. This statement particularly relevant for Georgia as the frequency of obesity is very high in the Georgian population.
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