共查询到20条相似文献,搜索用时 13 毫秒
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The resolution of scintillation spectrometers for -rays is influenced by several factors. In this paper a method for separately judging the individual factors is discussed. The influence of statistical processes in the photo-multiplier and the possibility of improving the resolution of the scintillation spectrometer by choosing the most suitable photo-multiplier and its working parameters is particularly studied. 相似文献
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Z. B. Marii L. P. Ellison B. G. Gowland G. A. Gledhill 《International Journal of Infrared and Millimeter Waves》1994,15(1):247-261
The mini-computer and control electronics of a Bruker 113v Fourier Transform Spectrometer (FTS), capable of 0.03 cm–1 resolution for frequencies up to 4000cm–1, have been replaced by an inexpensive IBM-PC 486-based system. The original performance is exceeded. JCAMP-DX standard is used for data exchange. The system can be adapted to any FTS or similar instrument which requires time domain data acquisition. 相似文献
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Carbon bonding environments in hydrogenated amorphous carbon films (a-C:H) deposited from an rf-biased methane plasma onto various substrates have been quantified by application of solid state13C NMR. A family of films were prepared by systematically varying the substrate bias voltage. Quantitative data on carbon chemistry in these films is required for modeling the impact of structure on mechanical and optical properties. A variety of NMR acquisition pulse sequences have been investigated to determine the conditions under which quantitative13C NMR data can be acquired in this system. The results indicate that data acquisition from this material requires different protocols than for the study of polymeric hydrocarbon films. With proper experimental design, NMR is an excellent technique for structural studies of these materials. 相似文献
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真空光电探测器件的发展动向及其应用陈举忠(南京电子器件研究所,210016)[摘要]介绍光电倍增管、高灵敏度高分辨率视像管、EBCCD/像增强器、条纹管类光电探测器的发展现状及其应用。关键词:光电探测器,光电倍增管,视像管,条纹管THEDEVELOP... 相似文献
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S. V. Zuyev E. S. Konobeevski M. V. Mordovskoy 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(5):350-354
A setup is described for detecting several charged and neutral particles in coincidence and determining their energy and time parameters. The CAEN DT5742 (DT5720) desktop digitizer based on a digital signal processor is chosen as a central element of the data acquisition system. Using measurements of the parameters of secondary particles in the d + 2H → 2He + 2n reaction as an example, it is shown that this configuration allows all necessary information to be collected using a minimal set of electronic units, while the processing of digitized signals offers broad opportunities for interpreting the obtained data. 相似文献
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Testing of a triple gas electron multiplier (GEM) with pixel-pads is
described. Images by scanning and suspending radioactive sources
were obtained by using 96 channels digital data acquisition (DAQ)
system which was composed of 96 8× 8~mm2 pads and
associated electronics channels. 相似文献
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Diffuse fluorescence tomography systems that employ highly sensitive photo-multiplier tubes for single-photon detection are pushing the sensitivity limits of the field. However, each of these detectors only offers a single data projection to be collected, implying these imaging systems either require many detectors or long scan times to collect full data sets for image reconstruction. This study presents a method of utilizing the time-resolved collection capabilities of time-correlated single-photon counting techniques to increase spatial resolution and to reduce the number of data projections to produce reliable fluorescence reconstructions. Experimental tissue phantom results demonstrate that using data at 10 time gates in the fluorescence reconstructions for only 40 data projections provided superior image accuracy when compared to reconstructions on 320 continuous-wave data projections. 相似文献
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J. Simpson 《Acta Physica Hungarica A》1997,6(1-4):253-264
Euroball is a European project to build a highly efficient and powerful gamma-ray spectrometer for nuclear structure spectroscopy. The project is an amalgamation of recent technical advances in detectors, electronics and data acquisition. In the first phase the spectrometer consists of 30 large single crystal Ge detectors, 26 Clover Ge detectors and 15 Cluster Ge detectors each with an associated suppression shield. The 239 individual Ge detector elements will have a total photopeak efficiency ∈ p of ≈ 10% and will enable the properties of the atomic nucleus to be studied with a sensitivity up to or better than 10?5 of the production cross-section. The elements of the spectrometer, including the detectors, the electronics and the data acquisition system, some of the planned ancillary detectors and the first results will be presented. Several developments are under investigation for the upgrade of Euroball for its second phase. These include an inner BGO ball for multiplicity and summed energy determination and inner particle detectors for charged particle identification. These developments will also be discussed. 相似文献
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Christoph Hahn Esther Menz Philip Pfäfflein Günter Weber Thomas Stöhlker 《X射线光谱测定》2020,49(2):338-341
With the unprecedented range of ion species and energies offered by the newly commissioned CRYRING facility, the availability of single ion detectors is of significant importance as part of standard instrumentation as well as for novel experiments. A detector system was constructed on the basis of the YAP:Ce crystal scintillator, which is at once radiation-hard, fast, and affordable. Results of a characterization experiment confirmed the feasibility of the setup for incident ion rates on the order of MHz and found a critical fluence of some 1013 cm−2 upon which the crystal is rendered locally blind to further ion irradiation. The device was first used in CRYRING commissioning runs in August and November 2018. Future efforts will complete the integration of the detector into the GSI control and data acquisition system MBS. 相似文献
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Kazuo Hayakawa Yuki Akiyama Yoshinori Tsukamoto Mikio Kurata Kenichi Yukihira Hiroyoshi Soejima Yutaka Yoshida 《Hyperfine Interactions》2012,206(1-3):79-82
We have been developing a “M?ssbauer Spectroscopic Microscope (MSM)” which consists of a focusing lens for 14.4?keV γ-rays and a high precision X–Y stage. The measuring system both for electrons and γ-rays combined with a new M?ssbauer driver, i.e., “a moving coil actuator with a liner encoder” enables us to measure the mapping images simultaneously corresponding to different spectral components. The system has a controlling system based on a LabVIEW program and a LIST mode data acquisition system (NIKI-GLASS/A3100). To investigate a correlation between the microstructure of a sample and 57Fe atoms, a scanning electron microscope (APCO/Mini-EOC) is also installed to this system. 相似文献
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Development and testing of a CW-EPR apparatus for imaging of short-lifetime nitroxyl radicals in mouse head 总被引:1,自引:1,他引:0
Sato-Akaba H Fujii H Hirata H 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,193(2):191-198
This article describes a method for reducing the acquisition time in three-dimensional (3D) continuous-wave electron paramagnetic resonance (CW-EPR) imaging. To visualize nitroxyl spin probes, which have a short lifetime in living organisms, the acquisition time for a data set of spectral projections should be shorter than the lifetime of the spin probes. To decrease the total time required for data acquisition, the duration of magnetic field scanning was reduced to 0.5 s. Moreover, the number of projections was decreased by using the concept of a uniform distribution. To demonstrate this faster data acquisition, two kinds of nitroxyl radicals with different decay rates were measured in mice. 3D EPR imaging of 4-hydroxy-2,2,6,6-tetramethylpiperidine-d17-1-15N-1-oxyl in mouse head was successfully carried out. 3D EPR imaging of nitroxyl spin probes with a half-life of a few minutes was achieved for the first time in live animals. 相似文献
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In this work we describe a wavelength-swept continuous-wave optical parametric oscillator (OPO) for the rapid acquisition of mid-infrared spectra spanning over hundreds of wavenumbers. Rapid tuning of a ytterbium-doped fibre pump laser resulted in the OPO idler tuning over 900 cm?1 in 3.36 ms at a resolution of 4.5 cm?1, within a total accessible range of 2.67 to 4.34 μm (2304–3752 cm?1). Predictable tuning characteristics allowed simple online calibration of recorded spectra for absolute mid-infrared frequency. The system thus offers a viable approach to broadband spectral acquisition in applications requiring high-radiance illumination. 相似文献
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Kevin G. Bath Henning U. Voss Deqiang Jing Stewart Anderson Barbara Hempstead Francis S. Lee Jonathan P. Dyke Douglas J. Ballon 《Magnetic resonance imaging》2009
In this report, we discuss the application of a methodology for high-contrast, high-resolution magnetic resonance microscopy (MRM) of murine tissue using a 3.0-T imaging system. We employed a threefold strategy that included customized specimen preparation to maximize image contrast, three-dimensional data acquisition to minimize scan time and custom radiofrequency resonator design to maximize signal sensitivity. Images had a resolution of 100×78×78 μm3 with a signal-to-noise ratio per voxel greater than 25:1 and excellent contrast-to-noise ratios over a 30-min acquisition. We quantitatively validated the methods through comparisons of neuroanatomy across two lines of genetically engineered mice. Specifically, we were able to detect volumetric differences of as little as 9% between genetically engineered mouse strains in multiple brain regions that were predictive of underlying impairments in brain development. The overall methodology was straightforward to implement and provides ready access to basic MRM at field strengths that are widely available in both the laboratory and the clinic. 相似文献
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《Magnetic resonance imaging》1998,16(7):829-837
The volume-selection performance was studied for single- and double-volume-of-interest (VOI) acquisition with the volume-selection method image-selected in vivo spectroscopy for 31P magnetic resonance spectroscopy. High-resolution signal profiles were measured using a phantom simulating a brain. Inside the phantom there was a small, remotely controlled, movable signal source filled with ortho-phosphoric acid. Signal profiles of the VOI were measured in three perpendicular directions for 1VOI (single VOI) and 2VOI (double VOI) acquisition. The measured signal profiles for both acquisitions were very similar, but they showed a discrepancy with regard to the intended VOI (iVOI). The transition regions were on average 3.8 mm and the average full width at half maximum of the signal profile was 30 mm for an iVOI size of 30130130 (mm3). No displacement was observed in the signal profiles. To avoid overlapping signal profiles, the minimum separation between two iVOIs was found to be 10 mm in our magnetic resonance (MR) system. A substantial negative signal contribution from regions outside the iVOI was measured in the y-direction for 1VOI acquisition and one of the two VOIs in 2VOI acquisition. The other VOI in 2VOI acquisition exhibited only minor contamination. The measurements presented underline the importance of detailed knowledge on the volume selection performance in in vivo magnetic resonance spectroscopy. 相似文献
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在狭小空间或是恶劣环境下进行数据采集,传统的数据采集设备占用空间大、传输速率慢,不方便携带。通过分析这些缺点,设计了一种基于WiFi无线网络技术的便携式的无线数据采集控制系统。整个系统包括数据采集单元、数据传输单元和数据控制单元三大部分。该数据采集控制系统能够在WiFi网络覆盖区域内,以手持Android小型终端为控制终端,以无线网络为传输通道,实时控制数据采集卡,并读取采集数据,即时数据可帮助用户更加可靠的分析实际情况,具有实际应用价值。 相似文献