73 research outputs found
Radiative Strength Functions for Dipole Transitions in Zr-90
Partial cross sections for the (p,gamma) reaction on the Y-89 nucleus that
were measured previously at proton energies between 2.17 and 5.00 MeV and which
were averaged over resonances were used to determine the absolute values and
the energy distribution of the strength of dipole transitions from
compound-nucleus states to low-lying levels of the Zr-90 nucleus. The data
obtained in this way were compared with the predictions of various models.Comment: 10 pages, 5 figure
Results of wavelet processing of the 2K-capture Kr-78 experiment statistics
Results of a search for Kr-78 double K-capture with the large low-background
proportional counter (2005-2008 years) at the Baksan Neutrino Observatory are
presented. An experimental method and characteristics of detectors are
described. Basic features of the digitized pulses processing using wavelet
transform are considered. With due account taken of the analysis of individual
noise characteristic it has been shown that the appropriate choice of both
wavelet characteristics and sequence of processing algorithms allows one to
decrease the background in the energy region of useful events with a unique set
of characteristics by ~2000 times. New limit on the half-life of Kr-78 with
regard to 2K-capture has been found: T_{1/2} >= 2.4E21 yrs (90% C.L.).Comment: 12 pages, 9 figure
Characteristics of proportional counter filled with CF and Xe additions
In this article the measurement results of proportional counter working
characteristics filled with CF and Xe (% Xe) additions at different
pressures ( ) are presented. We have found that a bit of Xe
addition reduces working voltage necessary to get the same gas amplification by
two times against pure CF, it improves as well the resolution of the
counter and increases limit gas amplification by more than ten times.Comment: 7 pages, 8 figure
Results of a search for daily and annual variations of the Po-214 half-life at the two year observation period
The brief description of installation TAU-2 intended for long-term monitoring
of the half-life value () of the Po is presented.
The methods of measurement and processing of collected data are reported. The
results of analysis of time series values with different time step are
presented. Total of measurement time was equal to 590 days. Averaged value of
the Po half-life was obtained s. The annual
variation with an amplitude , solar-daily variation
with an amplitude , lunar-daily variation with
an amplitude and sidereal-daily variation with an
amplitude were found in a series of
values. The maximal values of amplitude are observed at the moments when the
projections of the installation Earth location velocity vectors toward the
source of possible variation achieve its maximal magnitudes.Comment: Talk at The International Workshop on Prospects of Particle Physics:
"Neutrino Physics and Astrophysics" February 1 - Ferbuary 8, 2015,
Valday,Russia, 7 pages, 12 figure (to be published in PEPAN
The origin of the background radioactive isotope Xe-127 in the sample of Xe enriched in Xe-124
The results of investigation of Xe-127 radioactive isotope production in the
xenon sample enriched in Xe-124, Xe-126, Xe-128 are presented. The isotope is
supposed to be the source of the background events in the low-background
experiment on search for 2K-capture of Xe-124. In this work we consider two
channels of Xe-127 production: the neutron knock-out from Xe-128 nucleus by
cosmogenic muons and the neutron capture by Xe-126 nucleus. For the first
channel the upper limit of the cross section of Xe-127 production was found to
be sigma >= 0.007 barn at 95\% C.L. For the second channel the value obtained
for the cross section was found to be equal to sigma =(2.74+-0.4) barn, which
coincides well, within the statistical error, with reference value.Comment: Talk at The International Workshop on Prospects of Particle Physics:
"Neutrino Physics and Astrophysics" Ferbuary 1 - 8, 2015, Valday,Russia, 4
pages, 5 figures, 1 tabel (to be published in PEPAN
Comparative analysis of spectra of the background of the proportional counter filled with Kr, enriched in Kr-78, and with Kr of natural content
The results of the experiment searching for 2K-capture with large
low-background proportional counter are presented. The comparison of spectra of
the background of the proportional counter filled with Kr enriched in Kr
(8400 hr) and with natural Kr (3039 hr) is given. A new limit on the half-life
of Kr with regard to 2K-capture, T yrs (95%
C.L.) has been obtained.Comment: 4 pages, 7 postscript figures, talk at the XIV-th Int. School
"Particles and Cosmology
Search for 2K(2\nu)-capture of Xe-124
The results of a search for two neutrino mode of double K-capture of Xe-124
using a large copper low-background proportional counter are presented. Data
collected during 3220 hours of measurements with 58.6 g of Xe provides
us to a new limit on the half-life of Xe-124 regarding 2K-capture at the level:
T_{1/2} >= 2.0*10^{21} years at a 90\% confidence level.Comment: 9 pages, 4 figures, Talk at The International Workshop on Prospects
of Particle Physics: "Neutrino Physics and Astrophysics" February 01 -
Ferbuary 08, 2015, Valday, Russi
Sources of the systematic errors in measurements of Po-214 decay half-life time variations at the Baksan deep underground experiments
The design changes of the Baksan low-background TAU-1 and TAU-2 set-ups
allowed to improve a sensitivity of Po-214 half-life (\tau) measurements up to
the 2.5 x 10^{-4} are described. Different possible sources of systematic
errors influencing on the -value are studed. An annual variation of
Po-214 half-life time measurements with an amplitude of A=(6.9 \pm 3) x 10^{-4}
and a phase of (\phi=93 \pm 10) days was found in a sequence of the
week-collected \tau-values obtained from the TAU-2 data sample with total
duration of 480 days. 24 hours' variation of the \tau-value measurements with
an amplitude of A=(10.0 \pm 2.6) x 10^{-4} and phase of (\phi=1 \pm 0.5) hours
was found in a solar day 1 hour step \tau-value sequence formed from the same
data sample. It was found that the Po-214 half-life averaged at 480 days is
equal to (163.45 \pm 0.04) mks.Comment: 17 pages, 6 figures, accepted for publication in Journal of Physics
of Elementary Particles and Atomic Nucle
Radiative Strength Functions for Dipole Transitions in 57, 59Co
Average-resonance data on the (p,gamma) reaction on 56,58Fe that were taken
at proton energies of Ep=1.5-3.0 MeV are used to determine the absolute values
of the radiative strength functions for energies below 10 MeV. The results
obtained in this way are compared with the results of the calculations that
rely on the statistical approach and which take into account the temperature of
the nucleus and its shell structure. Good agreement with experimental data is
achieved without any variation of parameters.Comment: 6 pages, 6 figure
Force and magnetic field sensor based on measurement of tunneling conductance between ends of coaxial carbon nanotubes
The interaction and tunneling conductance between oppositely located ends of
coaxial carbon nanotubes are studied by the example of two (11,11) nanotubes
with open ends terminated by hydrogen atoms. The Green function formalism is
applied to determine the tunneling current through the nanotube ends as a
function of the distance between the ends, relative orientation of the
nanotubes and voltage applied. The energy favorable configuration of the
coaxial nanotubes is obtained by the analysis of their interaction energy at
different distances between the nanotube ends and angles of their relative
rotation. Using these calculations, a general scheme of the force sensor based
on the interaction between ends of coaxial nanotubes is proposed and the
relation between the tunneling conductance and measured force is established
for the considered nanotubes. The operational characteristics of this device as
a magnetic field sensor based on measurements of the magnetic force acting on
the coaxial nanotubes filled with magnetic endofullerenes are estimated.Comment: 9 pages, 8 figure
- …