Scintillation detectors experimental

The experimental equipment requires a standard fine structure X-ray generator operated usually with monochromatic K -radiation. The measurements of the refraction effect are taken by using a commercial small angle X-ray camera of the Kratky type in combination with two scintillation detectors for simultaneous detection of X-ray refraction intensity Ir and sample absorption U- A standard DOS-computer handles the scattering intensity data acquisition and the micromanipulator scanning-system. Figure 1 shows the experimental setup. 

CCD and other area detectors such as image plates permit large numbers of intensities to be measured simultaneously, in contrast to their forerunner scintillation detectors for which intensities were measured sequentially. Area detectors therefore facilitate multiple measurements of each diffraction intensity (or symmetry-related intensity) within a relatively short time period (hours). Averaging over the crystal symmetry then yields a unique set of intensities of greater accuracy than where only individual measurements have been made. Such extensive data sets containing multiple measurements of each intensity also permit excellent estimation and empirical correction for systematic errors such as absorption, and instrumental/ experimental errors such as minor misalignments of the instrument or crystal. 

X-ray diffraction measurements were conducted at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, beamline XI Ob. The experimental apparatus consisted of a six circle Huber diffractometer, ion chambers, and Bicron scintillation detectors. The step size was 0.020° and each point was scanned for approximately 13.8s. 

DCEMS together with low-temperature and in-field measurements require much more sophisticated experimental equipment. Gas counters, scintillation detectors, electron multipliers (Channeltron, Ceratron), surface barrier silicon semiconductor detector, and electron energy analyzers belong to the most frequently used detectors applied in CEMS and CXMS, respectively. Differences among individual constructions can be found in Ref. 123. Commercially available version of CEMS/CXMS spectrometer is depicted in Fig. 18.36 [127]. Device is based on 27t proportional continuous gas flow counter for room-temperature zero-magnetic field measurements. 

SAXS - measurements. SAXS curves were measured using a home-made KRM-1 diffractometer with a slit scheme for the primary beam collimation (CuKa-line, Ni filter, scintillation detector). The scattering coordinate was measured in terms of the scattering vector modulus s = 47t sinO/X, where 0 is the difraction angle, and X = 0.1542 nm is the radiation wavelength. The scattering intensity was measured in the range of s = 0.07 to 4.26 nm The experimental data were processed as described in 17-18). 

Scintillation detectors, especially in the case of inorganic crystals, constitute a seeond very important class of gamma ray detectors. In fact, they possess the requirements of high efficiency, fast response, low cost, good linearity whieh fulfill the experimental needs. The major drawback of scintillator detectors is their energy resolution that in the case of NaI Tl (one of the best and most used scintillators) is of the order of 40 keV at 662 keV, namely 40 times worse than that of HPGe detector. 

Fig. 9. Experimental setup for observation of ultrarelativistic A2e a) - channel scheme p - internal proton beam, T - film target, F - polyester film,CL - collimators, H -horizontal magnetic field, C - plexiglas converter b) - magnet and detectors MP - poles of spectrometer magnet, VC - vacuum chamber, DC1, DC2 and DC3 - drift chambers, SI and S2 - scintillation counters, C - gas Cherenkov counters...

Rare earth silicates exhibit potential applications as stable luminescent materials for phosphors, scintillators, and detectors. Silica and silicon substrates are frequently used for thin films fabrication, and their nanostructures including monodisperse sphere, NWs are also reliable templates and substrates. However, the composition, structure, and phase of rare earth silicates are rather complex, for example, there are many phases like silicate R2SiOs, disilicate R2Si207 (A-type, tetragonal), hexagonal Rx(Si04)602 oxyapatite, etc. The controlled synthesis of single-phase rare earth silicate nanomateriais can only be reached with precisely controlled experimental conditions. A number of heat treatment based routes, such as solid state reaction of rare earth oxides with silica/silicon substrate, sol-gel methods, and combustion method, as well as physical routes like pulsed laser ablation, have been applied to prepare various rare earth silicate powders and films. The optical properties of rare earth silicate nanocrystalline films and powders have been studied. 

Figure 1, Experimental set up A, lead shielding B, lead collimator C, thin-scintillator muon counter sends start signal to clock D, sample target E, coincident-decay positron detectors send stop signal to logic and clock F, graphite degrader G, magnetic field coils.

Fig. 3a-c Experimental set-ups for measuring X-ray absorption spectra, a Standard transmission experiment b set-up for fluorescence yield measurements c set-up for electron yield measurements placed in an ultra-high vacuum (UHV). So Synchrotron X-ray source, M double-crystal monochromator IC ionization chamber Sa sample RS reference sample for energy calibration, x fluorescence X-rays FD fluorescence detector (typically an energy-dispersive solid-state X-ray detector) e electrons emanated from the sample eD detector for electrons (typically a scintillation counter) s/scattering foil which scatters a small part of the X-ray beams into the X-ray detector (xD), so that the intensity of the incoming beam can be measured... 

In the method of delayed coincidences, the coincidence counting rate between detectors responding selectively to genetically related particles, e.g., a jS- or a-par-ticle and a y-ray or an electron or between y-rays, is plotted as a function of a time delay inserted in the electronic circuits used to detect one of them. The development of this method and of improved electronic techniques has led to the use of resolution times of between 10" and 10 sec. We shall not discuss these methods here, for they have been very adequately reported by Bell [i9], 2ff]. Further analysis of the experimental data has made it possible to measure lifetimes of the order of 10 sec. The limit to the method seems to be determined by the scintillating properties of the phosphor and its physical size. 

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