Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userLifetime measurements of 214Po and 212Po with the CTF liquid scintillator detector at LNGS
273
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We have studied the alpha decays of 214Po into 210Pb and of 212Po into 208Pb tagged by the coincidence with the preceding beta decays from 214Bi and 212Bi, respectively. The employed 222Rn, 232Th, and 220Rn sources were sealed inside quartz vials and inserted in the Counting Test Facility at the underground Gran Sasso National Laboratory in Italy. We find that the mean lifetime of 214Po is (236.00 +- 0.42(stat) +- 0.15(syst)) mu s and that of 212Po is (425.1 +- 0.9(stat) +- 1.2(syst)) ns. Our results, obtained from data with signal-to-background ratio larger than 1000, reduce the overall uncertainties and are compatible with previous measurements.
rate research
Read More
Precise measurement of half-life of $^{212}$Po (one of the daughter nuclides in radioactive chain of $^{232}$Th) was realized by means of liquid scintillator based on toluene doped by complex of thorium and trioctylphosphine oxide with concentration of Th $sim0.1$ mass %. Fast photomultiplier tube and high frequency oscilloscope were used to acquire the scintillation signals waveforms. The algorithms were developed to find pairs of $^{212}$Bi beta-decays and subsequent $^{212}$Po alpha-decays, to calculate time differences between the events in the pair, and to build $^{212}$Bi beta-decay and $^{212}$Po alpha-decay energy spectra. Preliminary the $^{212}$Po half-life is $T_{1/2} = (294.8 pm 1.9)$ ns. The experiment is in progress aiming at reduction of the statistical and systematic uncertainties.
We report a measurement of the neutrino-electron elastic scattering rate from 8B solar neutrinos based on a 123 kton-day exposure of KamLAND. The background-subtracted electron recoil rate, above a 5.5 MeV analysis threshold is 1.49+/-0.14(stat)+/-0.17(syst) events per kton-day. Interpreted as due to a pure electron flavor flux with a 8B neutrino spectrum, this corresponds to a spectrum integrated flux of 2.77+/-0.26(stat)+/-0.32(syst) x 10^6 cm^-2s^-1. The analysis threshold is driven by 208Tl present in the liquid scintillator, and the main source of systematic uncertainty is due to background from cosmogenic 11Be. The measured rate is consistent with existing measurements and with Standard Solar Model predictions which include matter enhanced neutrino oscillation.
Results on the search for rare nuclear decays with the ultra low background facility STELLA at the LNGS using gamma ray spectrometry are presented. In particular, the best T1/2 limits were obtained for double beta processes in 96Ru and 104Ru. Several isotopes, which potentially decay through different double beta decay channels, including also possible resonant double electron captures, were investigated for the first time (156Dy, 158Dy, 184Os, 192Os, 190Pt, 198Pt). Search for resonant absorption of solar 7Li axions in a LiF crystal gave the best limit for the mass of 7Li axions (< 8.6 keV). Rare alpha decay of 190Pt to the first excited level of 186Os (Eexc = 137.2 keV) was observed for the first time.
The photo production of $omega$ mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the $omega$ meson cross section on the nuclear mass number has been compared with three different types of models, a Glauber analysis, a BUU analysis of the Giessen theory group and a calculation by the Valencia theory group. In all three cases, the inelastic $omega$ width is found to be $130-150 rm{MeV/c^2}$ at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the restframe of the $omega$ meson, this inelastic $omega$ width corresponds to a reduction of the $omega$ lifetime by a factor $approx 30$. For the first time, the momentum dependent $omega$N cross section has been extracted from the experiment and is in the range of 70 mb.
Based on test-beam measurements, we study the response of a liquid-scintillator detector equipped with wavelength-shifting optical modules, that are proposed e.g. for the IceCube experiment and the SHiP experiment, and adiabatic light guides that are viewed either by a photomultiplier tube or by an array of silicon photomultipliers. We report on the efficiency, the time resolution and the detector response to different particle types and point out potential ways to improve the detector performance.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
