共查询到20条相似文献，搜索用时 15 毫秒
1.
M.J. Hwang Y.J. Kwon H.J. Kim J.W. Kwak S.C. Kim S.K. Kim T.Y. Kim S.Y. Kim H.S. Lee M.J. Lee S.S. Myung Y.D. Kim J.I. Lee W.G. Kang I.S. Hahn M.H. Lee KIMS Collaboration 《Astroparticle Physics》2009,31(6):412-416
A search for the neutrinoless double-beta decay of 124Sn was carried out using the tin-loaded liquid scintillator for an active source-detector technique. Tin (32.6%) in weight was successfully loaded into the liquid scintillator, and light output was as high as 57% of the unloaded liquid scintillator. A tin-loaded liquid scintillator with 1.1 ℓ volume was installed at the 700 m underground laboratory in YangYang, and data were taken for 5285 h. No evidence for the 0νββ decay was found and a lower limit on the 124Sn half-life was obtained to be 2.0×1019 year with 90% C.L. The new limit represents a significant improvement with respect to those previously available for 124Sn. 相似文献
2.
B andV light curves for one epoch and radial velocity curves of three different epochs have been analyzed to revise the solution of TX UMa. The solution has been adjusted simultaneously in the light curves and radial velocity curves by the method of Wilson and Devinney's differential correction. The primary star's surface rotation rate to synchronous rate is determined as 1.768 from one of the radial velocity curves. The absolute dimension of the system has been deduced based on the simultaneous solution. The primary star is well fitted to the evolutionary track for a single star while the secondary star, while filling its Roche lobe, is fitted to the evolutionary track for a close binary system. 相似文献
3.
S. Cecchini H. Dekhissi G. Giacomelli G. Mandrioli A. R. Margiotta L. Patrizii F. Predieri P. Serra M. Spurio 《Astroparticle Physics》1993,1(4):369-376
We present measurements of fragmentation cross sections of relativistic nuclei and upper limits for the production probability of nuclear fragments with fractional charge using CR39 nuclear track detectors and an automated scanning system. The measurements of the total and partial charge changing fragmentation cross sections concern 16 GeV/nucleon oxygen ions, 14.5 GeV/nucleon silicon ions and 200 GeV/nucleon sulphur ions interacting in copper and CR39 targets. No evidence for fractionally charged fragments was found requiring a minimum track length of 7 mm in CR39 detectors placed after a 14 mm copper target. The combined upper limit for the production probability of fractionally charged fragments relative to ordinary ones is at the level of 1.2–2.3 × 10–4 (90% C.L.). The charge resolution of the CR39 detectors for an average of 10 measurements of the same track is σ = 0.05e at Z = 6. 相似文献
4.
N. J. C. Spooner G. J. Davies C. H. Lally N. J. T. Smith M. van den Putte P. F. Smith J. D. Lewin G. T. A. Squier P. Jagpal 《Astroparticle Physics》1996,5(3-4):299-307
The UVIS dark matter detector, proposed by Spooner and Smith (Phys. Lett. B 314 (1993) 430), consists of < 1000 ppm Tl doped NaI scintillator operated at 100-200 K, with measurement of UV and visible scintillation components used to discriminate between electrons (gammas) and Na or I recoils. Presented here are results of measurements of the gamma/nuclear recoil discrimination power of a Kyropolous NaI (0.5 ppm Tl) UVIS test detector operated at 160 K, with monoenergetic neutrons used to induce nuclear recoils via elastic scattering. Defining the statistical gain factor for N events as
, the coefficient Cm was measured as a function of photoelectron pulse height. At 40 photoelectrons Cm was found to be 0.5 (corresponding to 90% rejection of gammas with 20% loss of neutron events). The scintillation efficiency for Na and I recoils relative to electrons was also measured at 160 K and found to be 35 ± 5% for Na recoils and 10 ± 2% for iodine. 相似文献
5.
《New Astronomy》2020
Results will be shown from the Astroneu array developed and operated in the outskirts of Patras, Greece. An array of 9 scintillator detectors and 3 antennas were deployed to study Extensive Air Showers (EAS) as a tool for calibrating an underwater neutrino telescope, possible other applications in muon tomography, education purposes, and last but not least, for the detection of air showers via their electromagnetic signature. In this work we concentrate to the electromagnetic detection of air showers presenting the operation of the RF system, as well as the analysis of the radio signals captured in coincidence with the scintillator detectors. We demonstrate the adequacy of the method to detect cosmic events even in the presence of high urban electromagnetic background, using noise filters, timing and signal polarization. The results are compared with well understood event reconstruction using the scintillator detectors and are indicating that cosmic showers were detected, proving that such small scale hybrid arrays can operate in strong background noise environments. 相似文献
6.
M. C. Chen 《Earth, Moon, and Planets》2006,99(1-4):221-228
There are plans to fill the Sudbury Neutrino Observatory with liquid scintillator after measurements with heavy water are
completed. The new experiment, known as SNO+, would make an excellent detector for geo-neutrinos. SNO+ would be located amidst
a thick and uniform region of continental crust, away from nuclear power reactors. As a result, the geo-neutrino signal to
reactor background ratio in SNO+ will exceed that from previous measurements. Geo-neutrino measurements by SNO+ will shed
light on the amount of uranium and thorium radioactivity in the crust, as well as deeper inside the Earth. Spectral information
from SNO+ geo-neutrino detection will provide the first direct measurement of the U/Th ratio. 相似文献
7.
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the neutron-induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.06 per year per kilogram, fully compatible with the design of a 10 kg × year exposure. 相似文献
8.
Roberto Battiston Maria Teresa Brunetti Franco Cervelli Cristiano Fidani Mauro Menichelli 《Astrophysics and Space Science》2009,323(4):357-366
We discuss an electromagnetic sampling calorimeter for the detection of very high energy gamma-rays on the Moon, which is
based on the use of scintillating cylinders and plates imbedded in the lunar soil. The use of lunar soil as a calorimeter
radiator reduces the weight of the material to be transported to the Moon and minimises environmental impact. Plastic scintillator
bars inserted into the regolith about 1.5 m are the active elements of this instrument: at the surface, each bar is terminated
by a plastic scintillator plate to veto high energy charge particles. The readout system for the scintillator bars and plates
are based on recently developed single photon solid state detectors (Silicon Photomultiplier, SiPM), extremely compact, sturdy
and sensitive devices suited for detecting small light pulses in a space experiment. The performance of a regolith-scintillator
calorimeter is evaluated and the relevant parameters are optimised using a GEANT4 simulation. 相似文献
9.
10.
硅微条探测器具有位置分辨高、响应快、低噪声、低功耗等优点,广泛应用在各大加速器试验中,测量粒子径迹.新世纪以来,逐渐应用于空间探测领域.计划中的"悟空"2号暗物质粒子探测卫星的硅微条探测器将至数十万计,将产生海量的原始数据.如何实现探测器快速实时的数据压缩,是其需要解决的一大难题.立足于面向空间应用的硅微条探测器在轨实时压缩算法,算法采用FPGA (Field-programmable Gate Array)搭建流水线结构的方式实现,在提高系统集成度、节省逻辑资源的同时,批量数据处理时最高可将数据压缩率提升至38.4 M通道/s.算法结构具有通用性,设计思想和方案将为"悟空"2号的径迹探测器的研制提供参考. 相似文献
11.
Tadao Mitsui 《Earth, Moon, and Planets》2006,99(1-4):265-273
As a possible design of a future geoneutrino detector, a KamLAND-type, monolithic, liquid scintillator detector with a thicker
veto and a method for particle identification to reject neutron and 9Li background from cosmic-ray muon spallation is considered. Assuming such a detector, the possibility for geoneutrino observation
at a depth of around 300 meters of water equivalent is investigated. 相似文献
12.
Mikhail Batygov 《Earth, Moon, and Planets》2006,99(1-4):183-192
The possibility of terrestrial antineutrino directionality studies is considered for future unloaded liquid scintillator detectors.
Monte-Carlo simulations suggest that the measurable displacement between prompt and delayed antineutrino signals makes such
studies possible. However, it is estimated that on the order of 1000 terrestrial antineutrino events are required to test
the simplest models, demanding detectors of 100 kt size to collect sufficient data in a reasonable period of time. 相似文献
13.
Abstract— Possible evidence for the presence of 248Cm in the early Solar System was reported from fission gas studies (Rao and Gopalan, 1973) and recently from studies of very high nuclear track densities (≥ 5 × 10g cm?2) in the merrillite of the H4 chondrite Forest Vale (F. V.) (Pellas et al., 1987). We report here an analysis of the isotopic abundances of xenon in F. V. phosphates and results of track studies in phosphate/pyroxene contacts. The fission xenon isotopic signature clearly identifies 244Pu as the extinct progenitor. We calculate an upper limit 248Cm/244Pu < 1.5 × 10?3 at the beginning of Xe retention in F. V. phosphates. This corresponds to an upper limit of the ratio 248Cm/235U ≤ 5 × 10?5, further constraining the evidence for any late addition of freshly synthesized actinide elements just prior to Solar System formation. The fission track density observed after annealing the phosphates at 290 °C (1 hr, which essentially erases spallation recoil tracks) is also in agreement with the 244Pu abundance inferred from fission Xe. The spallation recoil tracks produced during the 76 Ma cosmic-ray exposure account for the very high track density in merrillites. 相似文献
14.
Local correlation tracking (LCT) is a commonly used motion tracking technique, particularly in solar physics. When used to track motions smaller than one pixel per time sample, interpolation of the original data is required. We demonstrate that it is possible to introduce large systematic errors by using an inappropriate interpolation method, and describe how to avoid these errors. The effect of these errors on the calculated velocity field is demonstrated on simulated solar granulation data. 相似文献
15.
M. Bahmanabadi A. Anvari G. Rastegarzadeh J. Samimi M. Lamehi Rachti 《Experimental Astronomy》1998,8(3):211-229
We have carried out a series of measurements with twenty-one light enclosures of different geometry and inside finishes to compare their performance for use in extensive air shower experiments. It is found that for light enclosures with white inside finish there is an inherent induced uncertainty in time measurement, in addition to the uncertainty arising from the uncertain transit location of the shower particle in a large area scintillator. Both of these uncertainties which can not be improved with better electronics limit the angular resolution of EAS arrays. 相似文献
16.
K. Söderström S. Lindstam S. Behrnetz K. Kristiansson 《Astrophysics and Space Science》1973,21(1):211-222
The charge composition of the cosmic radiation for the elements withZ14 has been studied in a stack of nuclear emulsions exposed at Fort Churchill in July 1967. Particles stopping in the stack have been measured with a nuclear track photometer to determine the charge. Relative abundances are given for the elements silicon to nickel and comparison is made with other investigations. 相似文献
17.
18.
The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly’s Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown. 相似文献
19.
Toshihiko Kadono Rei Niimi Kyoko Okudaira Sunao Hasegawa Makoto Tabata Akira Tsuchiyama 《Icarus》2012,221(2):587-592
In order to understand the penetration process of projectiles into lower-density targets, we carry out hypervelocity impact experiments using low-density (60 mg cm?3) aerogel targets and various types of projectiles, and observe the track formation process in the targets using a high-speed camera. A carrot shaped track, a bulbous, and a “hybrid” one consisting of bulbous and thin parts, are formed. The results of the high-speed camera observations reveal the similarity and differences on the temporal evolution of the penetration depth and maximum diameter of these tracks. At very early stages of an impact, independent of projectile type, the temporal penetration depth is described by hydrodynamic models for the original projectiles. Afterward, when the breakup of projectiles does not occur, intact projectiles continue to penetrate the aerogels. In the case of the breakup of projectiles, the track expands with a velocity of about a sound velocity of the aerogel at final stages. If there are large fragments, they penetrate deeper and the tracks become a hybrid type. The penetration of the large fragments is described by hydrodynamic models. Based on these results, we discuss the excavation near the impact point by shock waves. 相似文献
20.
On the basis of solar flare forecasts, balloon flights were made from Hyderabad, India (vertical geomagnetic threshold rigidity of 16.9 GV), to detect the possible emission of high energy neutrons during solar flares. The detector comprised of a central plastic scintillator, completely surrounded by an anticoincidence plastic scintillator shield. The instrument responds to neutrons of about 15–150 MeV and gamma rays of about 5–30 MeV with about the same efficiency. The detector was flown to an atmospheric depth of 25 g cm-2 on February 26, 1969; while the balloon was at ceiling a flare of importance 2B and one of 1N occurred. No perceptible flare associated increase in the counting rate was observed. Using the observed counting rates, an upper limit of 1.2 × 10-2 neutrons cm-2 sec-1 is obtained for the first time for a flare of importance 2B for neutrons of energy 15–150 MeV. The corresponding upper limit for gamma rays of energy 5–30 MeV is found to be 10-2 photons cm-2 sec-1. The neutron flux limits are compared with the recent calculations of Lingenfelter. 相似文献