共查询到20条相似文献,搜索用时 375 毫秒
1.
由于受激元素所辐射的光子能量范围主要集中在100 keV~6 MeV之间,因此通过基于此能量范围的射线源模拟实验研究了采用锗酸铋(BGO)阵列相邻信号叠加实现能量高分辨率的新方法并分析比较了其性能。结果显示:对于较高能的光子,若仅使用单根BGO晶体产生的信号时不可能得到较好的能量分辨率;而当使用BGO阵列将该单晶体产生的信号与相邻晶体产生信号相加,则能谱质量会变得更佳。对于能量分辨率为90 keV的能量窗,通过模拟得到平均固有空间分辨率为3.938 mm (FWHM)。 相似文献
2.
V. A. Baskov B. B. Govorkov V. V. Polyanskii 《Bulletin of the Lebedev Physics Institute》2014,41(5):140-143
Cosmic-ray calibration of the 4-channel lead scintillation monitor with internal trigger shows that the consideration of only coinciding signals of counters placed in the monitor depth and detecting the final part of the high-energy photon shower, with signals of any other counters at the monitor top, detecting both the initial part of the high-energy photon shower and low-energy background photons, decreases the number of detected coincidences by a factor of 2–4. An increase in the number of such coincidences when using the monitor in the setup for studying neutral pion photoproduction on nuclei in the photon beam of the labeling system of the “PAKHRA” accelerator of the Lebedev Physical Institute makes it possible to separate the high-energy electromagnetic shower from the low-energy background and to monitor the beam photon energy. 相似文献
3.
Two-dimensional photon counting imaging detector based on a Vernier position sensitive anode readout
下载免费PDF全文
![点击此处可从《中国物理C(英文版)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
YAN Qiu-Rong ZHAO Bao-Sheng LIU Yong-An YANG Hao SHENG Li-Zhi WEI Yong-Lin 《中国物理C(英文版)》2011,35(4):368-373
A two-dimensional photon counting imaging detector based on a Vernier position sensitive anode is reported. The decode principle and design of a two-dimensionai Vernier anode axe introduced in detail. A photon counting imaging system was built based on a Vernier anode. The image of very weak optical radiation can be reconstructed by image processing in a period of integration time. The resolution is superior to 100 μm according to the resolution test. The detector may realize the imaging of very weak particle flow of high- energy photons, electrons and ions, so it can be used for high-energy physics, deep space exploration, spectral measurement and bio-luminescence detection. 相似文献
4.
The principle and design of a new photoemission electron microscope (PEEM), which is called Stereo-PEEM, is described here. Stereo-PEEM can display not only the image of microscopic materials but also the angular distribution of high-energy photoelectrons up to about ±60°, which is about 100-fold the acceptance angle of usual PEEM. This wide angle acceptance for high-energy photoelectrons enables the three-dimensional (3D) display of atomic structure as well as the 3D electronic structure of individual micromaterials. The 3D atomic structure of a sample can be observed directly by taking stereophotographs using photons with angular momentum. 相似文献
5.
6.
7.
A. M. Galper N. P. Topchiev R. L. Aptekar I. V. Arkhangelskaja M. Boezio V. Bonvicini A. Vacchi V. Ya. Gecha B. A. Dolgoshein N. Zampa V. G. Zverev V. A. Kaplin V. A. Kachanov E. P. Mazets A. L. Menshenin P. Picozza O. F. Prilutskii V. G. Rodin M. F. Runtso P. Spillantini S. I. Suchkov M. O. Farber M. I. Fradkin Yu. T. Yurkin 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):875-877
The GAMMA-400 telescope is designed to investigate discrete high-energy gamma-ray sources in the energy range of 0.1–3000 GeV, to measure the energy spectra of galactic and extragalactic diffuse gammaray emissions, and to study gamma-ray bursts and gamma-ray emissions from an active Sun. The gamma-ray telescope has an angular resolution of ~0.01°, an energy resolution of ~1%, and a proton rejection factor of ~106. Its special assignment is to measure fluxes of gamma rays, electrons, and positrons that could be associated with the annihilation or decay of dark matter particles. 相似文献
8.
DONG Yi-Fan ZHANG Fei QIAO Rui PENG Wen-Xi FAN Rui-Rui GONG Ke WU Di WANG Huan-Yu 《中国物理C(英文版)》2015,39(11):116202-116202
The Dark Matter Particle Explorer(DAMPE) is an upcoming scientific satellite mission for high energy gamma-ray, electron and cosmic ray detection. The silicon tracker(STK) is a subdetector of the DAMPE payload.It has excellent position resolution(readout pitch of 242 μm), and measures the incident direction of particles as well as charge. The STK consists of 12 layers of Silicon Micro-strip Detector(SMD), equivalent to a total silicon area of6.5 m2. The total number of readout channels of the STK is 73728, which leads to a huge amount of raw data to be processed. In this paper, we focus on the on-board data compression algorithm and procedure in the STK, and show the results of initial verification by cosmic-ray measurements. 相似文献
9.
V. E. Shebalin A. V. Anisenkov V. M. Aulchenko N. S. Bashtovoy D. A. Epifanov L. B. Epshteyn A. A. Grebenuk F. V. Ignatov A. L. Erofeev O. A. Kovalenko A. N. Kozyrev A. S. Kuzmin I. B. Logashenko K. Yu. Mikhailov G. P. Razuvaev A. A. Ruban B. A. Shwartz A. A. Talyshev V. M. Titov Yu. V. Yudin 《Physics of Atomic Nuclei》2015,78(13):1544-1551
The structure of the barrel calorimeter of the CMD-3 detector is presented in this work. The procedure of energy calibration of the calorimeter and the method of photon energy restoration are described. The distinctive feature of this barrel calorimeter is its combined structure; it is composed of two coaxial subsystems: a liquid xenon calorimeter and a crystalline CsI calorimeter. The calorimeter spatial resolution of the photon conversion point is about 2 mm, which corresponds to an angular resolution of ~6 mrad. The energy resolution of the calorimeter is about 8% for photons with energy of 200 MeV and 4% for photons with energy of 1 GeV. 相似文献
10.
Aubert B Bona M Karyotakis Y Lees JP Poireau V Prencipe E Prudent X Tisserand V Garra Tico J Grauges E Lopez L Palano A Pappagallo M Eigen G Stugu B Sun L Abrams GS Battaglia M Brown DN Cahn RN Jacobsen RG Kerth LT Kolomensky YG Lynch G Osipenkov IL Ronan MT Tackmann K Tanabe T Hawkes CM Soni N Watson AT Koch H Schroeder T Walker D Asgeirsson DJ Fulsom BG Hearty C Mattison TS McKenna JA Barrett M Khan A Blinov VE Bukin AD Buzykaev AR Druzhinin VP Golubev VB Onuchin AP Serednyakov SI Skovpen YI 《Physical review letters》2008,101(7):071801
We report the results of a search for the bottomonium ground state etab(1S) in the photon energy spectrum with a sample of (109+/-1) million of Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at Egamma=921.2(-2.8)+2.1(stat)+/-2.4(syst) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Upsilon(3S)-->gammaetab(1S). This photon energy corresponds to an etab(1S) mass of 9388.9(-2.3)+3.1(stat)+/-2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-etab(1S) mass splitting is 71.4(-3.1)+2.3(stat)+/-2.7(syst) MeV/c2. The branching fraction for this radiative Upsilon(3S) decay is estimated to be [4.8+/-0.5(stat)+/-1.2(syst)]x10(-4). 相似文献
11.
The production and transportation of fluorescent light produced in wavelength-shifting fibers (WSFs) coupled to YAP scintillation crystal is simulated using the GEANT4 codes. An advantage of the wavelength-shifting fiber readout technique over a direct readout with a position-sensitive photo-sensor is the reduced requirement for position sensitive photomultiplier tube photocathode area. With this gamma-ray detector, the gamma camera is small and flexible and has larger effective field of view and low cost. Simulation results show that a) a mean 12 of photons per 59.5 keV gamma ray interaction is produced in the WSF located nearest to the incident gamma ray, and a spatial resolution of 3.6 mm FWHM is obtained, b) a mean 27 of photons per 140 keV gamma ray interaction is produced and a spatial resolution of 3.1 mm FWHM is obtained. Results demonstrate the feasibility of this concept of a compact gamma-ray detector based on wavelength-shifting fibers readout. However, since the very low photoelectron levels, it is very important to use a photon counting device with good single photo-electron response to readout the WSFs. 相似文献
12.
The production and transportation of fluorescent light produced in wavelength-shifting fibers (WSFs) coupled to YAP scintillation crystal is simulated using the GEANT4 codes.An advantage of the wavelength-shifting fiber readout technique over a direct readout with a position-sensitive photo-sensor is the reduced requirement for position sensitive photomultiplier tube photocathode area.With this gamma-ray detector,the gamma camera is small and flexible and has larger effective field of view and low cost.Simulation results show that a) a mean 12 of photons per 59.5 keV gamma ray interaction is produced in the WSF located nearest to the incident gamma ray,and a spatial resolution of 3.6 mm FWHM is obtained,b)a mean 27 of photons per 140 keV gamma ray interaction is produced and a spatial resolution of 3.1 mm FWHM is obtained.Results demonstrate the feasibility of this concept of a compact gamma-ray detector based on wavelength-shifting fibers readout.However,since the very low photoelectron levels,it is very important to use a photon counting device with good single photo-electron response to readout the WSFs. 相似文献
13.
Tony Warwick Yi‐De Chuang Dmitriy L. Voronov Howard A. Padmore 《Journal of synchrotron radiation》2014,21(4):736-743
The optical design of a two‐dimensional imaging soft X‐ray spectrometer is described. A monochromator will produce a dispersed spectrum in a narrow vertical illuminated stripe (~2 µm wide by ~2 mm tall) on a sample. The spectrometer will use inelastically scattered X‐rays to image the extended field on the sample in the incident photon energy direction (vertical), resolving the incident photon energy. At the same time it will image and disperse the scattered photons in the orthogonal (horizontal) direction, resolving the scattered photon energy. The principal challenge is to design a system that images from the flat‐field illumination of the sample to the flat field of the detector and to achieve sufficiently high spectral resolution. This spectrometer provides a completely parallel resonant inelastic X‐ray scattering measurement at high spectral resolution (~30000) over the energy bandwidth (~5 eV) of a soft X‐ray absorption resonance. 相似文献
14.
《中国物理C(英文版)》2016,(8)
The DArk Matter Particle Explorer is an orbital indirect dark matter search experiment which measures the spectra of photons,electrons and positrons originating from deep space.The electromagnetic calorimeter(ECAL),made of bismuth germinate(BGO),is one of the key sub-detectors of DAMPE,and is designed for energy measurement with a large dynamic range from 5 GeV to 10 TeV.In this paper,methods for energy correction are discussed,in order to reconstruct the primary energy of the incident electrons.Different methods are chosen for the appropriate energy ranges.The correction results of Geant4 simulation and beam test data(at CERN) are presented. 相似文献
15.
V. B. Petkov E. V. Bugaev P. A. Klimai M. V. Andreev V. I. Volchenko G. V. Volchenko I. M. Dzaparova D. D. Dzhappuev A. N. Gaponenko Zh. Sh. Guliev N. F. Klimenko A. U. Kudzhaev A. V. Sergeev N. S. Khaerdinov A. B. Chernyaev A. F. Yanin 《Journal of Experimental and Theoretical Physics》2010,110(3):406-416
The energy spectra and temporal characteristics of high-energy gamma-ray bursts from evaporating primordial black holes have been calculated using various evaporation models. The currently existing theoretical uncertainties in the shape of the evaporated photon spectrum are discussed. The data from the Andyrchy and Carpet-2 arrays of the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) obtained in the mode of detection of a single cosmic-ray component are used to search for cosmic gamma-ray bursts with a primary photon energy of about 8 GeV. New upper limits have been obtained for the number density of evaporating black holes in a local region of space with a characteristic size of ~10?3 pc for various evaporation models. 相似文献
16.
Berezhiani Zurab Dolgov A. D. Tkachev I. I. 《The European Physical Journal C - Particles and Fields》2013,73(10):1-9
We look for possible spectral features and systematic effects in the Fermi LAT publicly available high-energy gamma-ray data by studying photons from the Galactic center, nearby galaxy clusters, nearby brightest galaxies, AGNs, unassociated sources, hydrogen clouds and from the Earth limb. Apart from the already known 130 GeV gamma-ray excesses from the first two sources, we find no statistically significant excesses from any of the cosmological sources nor from any control region. Therefore our main effort goes to the study of gamma rays appearing from the Earth limb. In the energy range of 30 to 200 GeV the Earth limb gamma-ray spectrum follows a power-law with spectral index 2.86±0.05 at 95 % CL, in a good agreement with the PAMELA measurement of the cosmic ray proton spectral index of 2.82–2.85, confirming the physical origin of the limb gamma-rays. In subsets of the Earth limb data at small photon incidence angle spectral features occur, including a feature at 130 GeV. We observe a systematic ~2σ-level difference in the Earth limb spectra with small and large incidence angles. The behavior of those spectral features as well as the background indicates that those may be statistical fluctuations or complicated unknown systematic effects of the Fermi LAT. In the latter case, only the Fermi LAT Collaboration can give the final answer having access to raw data and all details of the reconstruction. 相似文献
17.
T. de Reus J. Reinhardt B. Müller U. Müller G. Soff W. Greiner 《Zeitschrift für Physik A Hadrons and Nuclei》1985,321(4):589-592
We show that emission of high-energy electrons and photons in nuclear collisions at intermediate energies is sensitive to the space-time evolution of the reaction. The electron and photon spectra measure related but complementary quantities connected with the nuclear charge distribution. We show that at 60 MeV/u beam energy production of 50 MeV electrons is predicted to measurable probability. 相似文献
18.
Battesti R Fouché M Detlefs C Roth T Berceau P Duc F Frings P Rikken GL Rizzo C 《Physical review letters》2010,105(25):250405
In this Letter we describe our novel photon regeneration experiment for the axionlike particle search using an x-ray beam with a photon energy of 50.2 and 90.7 keV, two superconducting magnets of 3 T, and a Ge detector with a high quantum efficiency. A counting rate of regenerated photons compatible with zero has been measured. The corresponding limits on the pseudoscalar axionlike particle-two-photon coupling constant is obtained as a function of the particle mass. Our setup widens the energy window of purely terrestrial experiments devoted to the axionlike particle search by coupling to two photons. It also opens a new domain of experimental investigation of photon propagation in magnetic fields. 相似文献
19.
Study of Lorentz violation in INTEGRAL gamma-ray bursts 总被引:1,自引:0,他引:1
Raphael Lamon Nicolas Produit Frank Steiner 《General Relativity and Gravitation》2008,40(8):1731-1743
We search for possible time lags caused by quantum gravitational effects using gamma-ray bursts (GRBs) detected by INTEGRAL.
The advantage of this satellite is that we have at our disposal the energy and arrival time of every detected single photon,
which enhances the precision of the time resolution. We present a new method for seeking time lags in unbinned data using
a maximum likelihood method and support our conclusions with Monte Carlo simulations. The analysis establishes a conservative
lower bound on the Lorentz invariance violation scale, which is several orders of magnitude below the Planck mass, whose value
may however increase if better statistics of GRBs were available. Furthermore, we disagree with previous studies in which
a non-monotonic function of the redshift was used to perform a linear fit. 相似文献
20.
《中国科学:物理学 力学 天文学(英文版)》2016,(1)
Ice Cube has reported the detection of a diffuse Te V-Pe V neutrino emission, for which the flat spectrum radio quasars(FSRQs) have been proposed to be the candidate sources. Here we assume that the neutrino flux from FSRQs is proportional to their gamma-ray ones, and obtain the gamma-ray/neutrino flux ratio by the diffuse gamma-ray flux from Fermi-LAT measurement of FSRQs and the diffuse neutrino flux detected by Ice Cube. We apply this ratio to individual FSRQs and hence predict their neutrino flux. We find that a large fraction of candidate FSRQs from the northern sky in the Ice Cube point source search has predicted neutrino flux above the Ice Cube upper limit; and for the sample of stacking search for neutrinos by Ice Cube, the predicted stacked flux is even larger than the upper limit of stacked flux by orders of magnitude. Therefore the Ice Cube limit from stacking searches, combined with the Fermi-LAT observations, already rejects FSRQs as the main sources of Ice Cube-detected diffuse neutrinos: FSRQs can only account for 10%( 4%) of the Ice Cube-detected diffuse neutrino flux, according to the stacking searches from the whole(northern) sky. The derived small neutrino/gamma-ray flux ratio also implies that the gamma-ray emission from FSRQs cannot be produced by the secondary leptons and photons from the pion production processes. The caveat in the assumptions is discussed. 相似文献