排序方式: 共有25条查询结果,搜索用时 15 毫秒
1.
S. S. Belyshev L. Z. Dzhilavyan Yu. N. Pokotilovski 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(5):566-571
The emission of γ-quanta, electrons, and positrons upon the decay of 12N and 12B produced in characteristic targets is calculated within radiation–matter interaction models generated using the GEANT and MCNP simulation software. 相似文献
2.
Al. Yu. Muzychka Yu. N. Pokotilovski P. Geltenbort 《Journal of Experimental and Theoretical Physics》1999,88(1):79-83
We present results of a search for anomalous low-energy upscattering of ultracold neutrons from a beryllium surface. This
upscattering is considered one for the possible reasons for UCN “disappearance” from very cold beryllium bottles, as observed
in experiments. The indium foil activation method was used to measure a very low intensity flux of upscattered UCN. The (15–300)
m/s velocity range of upscattered UCN is ruled out by these measurements at a confidence level of 90%.
Zh. éksp. Teor. Fiz. 115, 141–148 (January 1999)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
3.
A. Frei Yu. Sobolev I. Altarev K. Eberhardt A. Gschrey E. Gutsmiedl R. Hackl G. Hampel F. J. Hartmann W. Heil J. V. Kratz Th. Lauer A. Liźon Aguilar A. R. Müller S. Paul Yu. Pokotilovski W. Schmid L. Tassini D. Tortorella N. Trautmann U. Trinks N. Wiehl 《The European Physical Journal A - Hadrons and Nuclei》2007,34(2):119-127
The production rates of ultracold neutrons (UCN) with a solid deuterium converter have been measured at the pulsed reactor
TRIGA Mainz. Exposed to a thermal neutron fluence of
n·cm^-2·pulse^-1, the number of detected very cold and ultracold neutrons ranges up to 200 000 at 7mol of solid deuterium
(sD2) in combination with a pre-moderator (mesitylene). About 50% of the measured neutrons can be assigned to UCN with energies
E of
where V
F(sD
2) = 105 neV and V
F(guide) = 190 neV are the Fermi potentials of the sD2 converter and our stainless steel neutron guides, respectively. Thermal cycling of solid deuterium, which was frozen out
from the gas phase, considerably improved the UCN yield, in particular at higher amounts of sD2. 相似文献
4.
5.
Present status of the measurements of the neutron lifetime is shortly reviewed. We report the inelastic neutron scattering measurement of the density of vibrational states G(ω) of two fluoropolymers, which are promising coating materials for the storage of ultracold neutrons (UCNs) in closed volumes covered with polymer film. From determined G(ω), we calculate the expected UCN loss coefficients. 相似文献
6.
Yu. N. Pokotilovski 《JETP Letters》2013,96(12):751-753
The chameleon scalar field is considered as a possible cause of accelerated expansion of the Universe. The chameleon field induces an interaction potential between particle and massive body. Previous experiments with falling cold neutrons intended to measure the neutron coherent scattering lengths and verification of the weak equivalence principle for the neutron are used to constrain the parameters characterizing the strength of the scalar chameleon fields. 相似文献
7.
S.Y. Yang J.J. ChiehW.C. Wang C.Y. YuN.S. Hing H.E. Horng Chin-Yih Hong H.C. Yang C.F. ChangH.Y. Lin 《Journal of magnetism and magnetic materials》2011,323(6):681-685
In this work, we investigate the feasibility of detecting quantitatively DNA molecules utilizing the technology named after the immunomagnetic reduction (IMR) assay. Magnetic nanoparticles dispersed in a phosphate buffer saline solution were bio-functionalized with probing single-strand DNA. A superconducting quantum interference device (SQUID) ac magnetosusceptometer was employed to detect IMR signals related to the concentration of the target DNA. The results reveal that use of IMR assay had merits such as a high convenience level, e.g. wash-free processes and high sensitivity, down to pM, for DNA detection. 相似文献
8.
Yu. N. Pokotilovski 《JETP Letters》2011,94(6):413-417
The consideration is presented of possible neutron experiments to search for new short-range spin-dependent forces. The spin-dependent
nucleon-nucleon interaction between neutron and nuclei may cause different effects: phase shift of a neutron wave in neutron
interferometers of different kind, in particular of the Lloyd mirror configuration, neutron spin rotation in the pseudo-magnetic
field, and transverse deflection of polarized neutron beam by a slab of substance. Estimates of sensitivity of these experiments
are performed. 相似文献
9.
Yu. N. Pokotilovski 《JETP Letters》2002,75(3):131-134
The method of pulse duration control is proposed for intense molecular beams. The method is based on the shortening of a primary molecular-beam pulse through the formation of a pressure shock ahead of a solid surface through which the beam is passed. The method was used to obtain intense SF6, H2, He, SF6/H2 (1/10), and SF6/He (1/10) molecular beams with a pulse duration of ≤10?15 μs and a spatial length of ≤1?2 cm. 相似文献
10.
Atchison F Blau B Bodek K van den Brandt B Bryś T Daum M Fierlinger P Frei A Geltenbort P Hautle P Henneck R Heule S Holley A Kasprzak M Kirch K Knecht A Konter JA Kuźniak M Liu CY Morris CL Pichlmaier A Plonka C Pokotilovski Y Saunders A Shin Y Tortorella D Wohlmuther M Young AR Zejma J Zsigmond G 《Physical review letters》2007,99(26):262502
A measurement of the production of ultracold neutrons from velocity-selected cold neutrons on gaseous and solid deuterium targets is reported. The expected energy dependence for two-particle collisions with well defined neutron and Maxwell-Boltzmann distributed molecular velocities is found for the gas target. The solid target data agree in shape with the phonon density-of-states curve and provide strong evidence for the phonon model including multiphonon excitations. 相似文献