Showing papers on "Scintillation published in 1991"

Cerium-doped lutetium oxyorthosilicate: a fast, efficient new scintillator

Abstract: The authors discuss a single-crystal inorganic scintillator, cerium-doped lutetium oxyorthosilicate (Lu/sub 2(1-x)/Ce/sub 2x/(SiO/sub 4/) or LSO). It has a scintillation emission intensity which is approximately 75% of NaI(Tl) with a decay time of approximately 40 ns. The peak emission wavelength is 420 nm. It has a very high gamma-ray detection efficiency due to its density of 7.4 g/cm/sup 3/ and its effective atomic number of 66. Its radiation length of 1.14 cm is only slightly longer than bismuth germanate (BGO). The scintillation properties of Ce-doped LSO are compared to NaI(Tl), BGO, and cerium-doped gadolinium oxyorthosilicate (GSO). In addition to desirable physical properties such as high density and high atomic number, LSO also processes a combination of high emission intensity and fast decay which together are superior to any other known single crystal scintillator. >

Liquid Scintillation Counting and Organic Scintillators

Abstract: PME, A Model Scintillation Salute with a Large Stokes' Shift. Scintillation Counting of Harvested Biological Samples with Low Energy Beta Emitters Using Solid Scintillant Filters. Di-isopropylnaphthalene-A New Solvent for Liquid Scintillation Counting. Safe Scintillation Chemicals for High Efficiency, High Throughout Counting. New Organic Scintillators. Advances in Scintillation Cocktails. Solidifying Scintillators for Solid Support Samples. New Red-emitting Liquid Scintillator with Decay Times Near One Nanosecond. New Developments in X-Ray Sensitive Liquid Scintillators Act Egg/em*. Liquid Scintillation Alpha Spectrometry: A Method for Today and Tomorrow. Application of High Purity Synthetic Quartz Vials to Liquid Scintillation Low Level 14C Counting of Benzene. An Introduction to Flat-bed ISC: The One Word Beta Plate Counter. A New, Rapid Analysis Technique for Quantitation of Radioactive Samples Isolated on a Solid Support. Dynodic Efficiency of Beta Emitters. Solid Scintillation Counting: A New Technique-Theory and Applications. Photon Scattering Effects in Heterogeneous Scintillator Systems. Some Factors Affecting Alpha Particle Detection in Liquid Scintillation Spectrometry. Modern Techniques for Quench Correction and DPM Determination in Windowless Liquid Scintillation Counting: A Critical Review. Multi-label Counting Using Digital Overlay Technique. A New Quench Curve Fitting Procedure: Fine-tuning of a Spectrum Library. The Effect on Quench Curve Shape of the Solvent and Quencher in a Liquid Scintillator Counter. Modem Applications in Liquid Scintillation Counting. A New Procedure for Multiple Isotope Analysis in Liquid Scintillation Counting. The Standardization of Beta-gamma Emitting Nuclides by Liquid Scintillation Counting. The Standardization of Sulphur-35 Methionine by Liquid-Scintillation Efficiency Tracing with Hydrogen-3. A Review and Experimental Evaluation of Commercial Radiocarbon Dating Software. Efficiency Extrapolation Adapted to Liquid Scintillation Counters. Applications of Quench Monitoring Using Transformed External Standard Spectrum (tSIE). Scintillation Proximity Assay: Instrumentation Requirements and Performance. The ISC Approach to Radon Counting in Air and Water. Liquid Scintillation Screening Method for Isotopic Uranium in Drinking Water. Assessment and Assurance of the Quality in the Determination of Low of Tritium in Ground Water. Use of Liquid Scintillation in the Appraisal of Nonradioactive Waste Shipments from Nuclear Facilities. Development of Aqueous Tritium Effluent Monitor. Rapid Termination of PU Content on Filters and Smears Using Alpha Liquid Scintillation. Vagaries of Wife Testing Data. The Determination of 234TH in Water Column Studies by Liquid Scintillation Counting. Performance of Small Quartz Vials in a Low Level, High Resolution Liquid Scintillation Spectrometer. The Optimization of Scintillation Counters Employing Burst Counting Circuitry. Statistical Considerations of Very Low Background Countrates in Liquid Scintillation Spectrometry with Applications to Radiocarbon Dating. Liquid Scintillation Counting Performance Using Glass Vials in the Wallac 1,220 Quantulus(TM). Time Resolved Liquid Scintillation Counting. Comparison of Various Anticoincident Shields in Liquid Scintillation Counters. The Effect of Altitude on the Background of Low Level Liquid Scintillation Counter. Calculational Method for the Resolution of Strontium-90/Strontium-89 Counts from Cerenkov and Liquid Scintillation Counting. Determination of RN-222 and RA-226 in Drinking Water by Low Level Liquid Scintillation Counting-Surveys in Austria and Arizona. A New Simplified Determination Method for Environmental SR-90 by Ultra Low Level Liquid Scintillation Counting. Mixed Waste-A Review from a Generator's Perspective. Disposal of Scintillation Cocktails. Liquid Scintillation Waste. Liquid Scintillation Counting of Radon and Its Daughters. LSC Standardization of P-32 in Inorganic and Organic Samples by the Efficiency Tracing Method. ANSI Standards for Liquid Scintillation Counting. A General Method for Determining Sample Efficiencies in Liquid Scintillation Counting. Absolute Activity Liquid Scintillation Counting: An Attractive Alternative to Quench-Corrected DPM for Higher Energy Isotopes. Chemical and Color Quench Curves Over Extended Quench Ranges. The Characteristics of the CH Number Method in Liquid Scintillation Counting. Low Level Scintillation Counting With a LKB Quantulus Counter. 600 pp.

A linear array, scintillation crystal-photodiode detector for megavoltage imaging

Abstract: An imaging device has been developed to acquire images during external photon-beam radiotherapy treatments. It consists of a linear array of 128 zinc tungstate (ZnWO4) scintillation crystals each of which is individually optically coupled to a photodiode and associated electronics. The image is formed by scanning the linear array across the radiation field using a stepping motor under the control of a microcomputer. Image archive, display, and analysis are performed using a microVAX II computer. Results from a general theoretical analysis are presented before a detailed description of the particular detector construction. The mechanical design of the detector is such that the detector is automatically positioned to within a millimeter relative to the treatment source. This simplifies procedures for analyzing setup variations when comparing a treatment image to any other treatment, or planning, images. Image acquisition takes under 4 s with a contrast resolution of better than 1% at a spatial resolution of 2.5 mm in the object plane. The primary dose used to form these images is 0.55 cGy although the dose received by the patient will be closer to 25 cGy due to the linear scanning geometry and 3.8-s scan time that is used.

Characteristics of fading on low-elevation angle Earth-space paths with concurrent rain attenuation and scintillation

Abstract: Signal-level variations on Ku-band low-elevation Earth-space paths, where large signal fades due to rain and tropospheric scintillations sometimes occur simultaneously, are examined. The difference in the amplitude variation rate for rain attenuation and scintillation fading is used to extract the effects of the two phenomena individually from raw data with the aid of a filtering technique. Characteristics of signal fading during rain are discussed on the basis of the analysis. It is shown that the decrease of signal level due to scintillation is much smaller than that due to rain attenuation, particularly for time percentages below 0.1%. However, for time percentages above about 1%, the effect of scintillation becomes dominant and no longer negligible, particularly for low-margin systems operating at low elevation angles. >

New radiation detector of plastic scintillation fiber

Abstract: Fundamental characteristics of a new plastic scintillation fiber (PSF) has been studied for four kinds of radiations, and the possibility of using the PSF as a radiation detector has been discussed. Irradiation experiments of scintillation output characteristics have been made for γ rays, x rays, fast neutrons, and α particles. Various scintillation pulse height spectra have been obtained, depending on the variations of radiation types, energies, intensities, and scintillating positions on the PSF. Position detection experiments have been also made for γ rays and fast neutrons, and a new position sensitive detector of the PSF has been proposed.

Precise measurement of Birks kB parameter in plastic scintillators

Abstract: The scintillation response of different types of plastic scintillators to electrons and protons was studied experimentally with high precision. Equivalent electron and proton energies yielding the same amount of light output have been measured. The results were analyzed in terms of a semiempirical formula proposed by Birks (1951). The results of the present experiment show that the reproducibility of experimentally determined kB values is better than +or-2%. This demonstrates the advantages of the time-of-flight method. As a consequence it was necessary to replace the very simple electron response function, L/sub e/(E) used in earlier publications by a more realistic description. The improved analysis was performed for SCSN-38 and NE 102A. In the present experiment the lowest kB value, i.e., the lowest loss of excitation energy due to radiationless quenching of fluorescence light, was observed for the scintillator SGSN-38 which is used in the ZEUS calorimeter. >

New approaches to spectroscopy and imaging of ultrasoft-to-hard X-rays

Abstract: We propose new techniques of X-ray spectroscopy and imaging, based on the use of low-pressure multistep gaseous electron multipliers. Ultrasoft X-rays are detected by counting single-electron clusters induced in the gas. X-ray induced UV-photons in gas scintillation chambers are read out with wire chambers coupled to CsI photocathodes. X-rays converted in foil-electrodes are imaged by fast multistep avalanche electron multipliers. We discuss the advantages of the various techniques and present experimental results and Monte Carlo simulations.

Particle detector spatial resolution

Abstract: Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector.

The Wide Band Spectrometer on the SOLAR-A

Abstract: The SOLAR-A spacecraft has spectroscopic capabilities in a wide energy band from soft X-rays to gamma-rays. The Wide Band Spectrometer (WBS), consisting of three kinds of spectrometers, soft X-ray spectrometer (SXS), hard X-ray spectrometer (HXS) and gamma-ray spectrometer (GRS), is installed on SOLAR-A to investigate plasma heating, high-energy particle acceleration, and interaction processes. SXS has two proportional counters and each counter provides 128-channel pulse height data in the 2–30 keV range every 2 s and 2-channel pulse count data every 0.25 s. HXS has a Nal scintillation detector and provides 32-channel pulse height data in the 20–400 keV range every 1 s and 2-channel pulse count data every 0.125 s. GRS has two identical BGO scintillation detectors and each detector provides 128-channel pulse height data in the 0.2–10 MeV range every 4 s and 4-channel pulse count data (0.2–0.7, 0.7–4, 4–7, and 7–10 MeV) every 0.25–0.5 s. In addition, each of the BGO scintillation detectors provides 16-channel pulse height data in the 8–100 MeV range every 4 s and 2-channel pulse count data (8–30 and 30–100 MeV) every 0.5 s. The SXS observations enable one to study the thermal evolution of flare plasma by obtaining time series of electron temperatures and emission measures of hot plasma; the HXS observations enable one to study the electron acceleration and heating mechanisms by obtaining time series of the electron spectrum; and the GRS observations enable one to study the high-energy electron and ion acceleration and interaction processes by obtaining time series of electron and ion spectra.

Temperature dependence of absolute CsI(Tl) scintillation yield

Abstract: A 1 cm*1 cm right cylindrical CsI(Tl) crystal was mounted on a 1 cm*1 cm square photodiode to measure the absolute scintillation yield of CsI(Tl) between -80 degrees C and 50 degrees C. A maximum yield of 65900+or-3300 photons/MeV was measured at 36 degrees C. While the scintillation yield at -80 degrees C is about 57% of the maximum, the yield is approximately constant in the range of -15 to 40 degrees C, at an average of 64600+or-3200 photons/MeV. Consideration is also given to the temperature dependence of the scintillation decay time, the scintillation emission spectrum, and the wavelength-dependent photodiode quantum efficiency. >

The Earth as an Antineutrino star

Abstract: Antineutrinos are emitted in the Earth upon β decays of radioactive elements and reach the surface with little interaction with terrestrial materials. These antineutrinos are anticipated to carry unique information about the chemistry and energetics of the Earth. We make a systematic search for the candidate target materials that undergo nuclear reactions with incoming antineutrinos and therefore that could be used as an antineutrino detector. The target nuclides most preferable for the measurement are 3He and 1H. For 3He we suggest a liquid 3He scintillation counter, of which practicability depends on the feasibility of amassing at least 10 ton of 3He. For 1H we may design a H2O or liquid H2 scintillation counter with an appropriate activator, which should be capable of detecting scintillation light in a huge tank containing at least 104 ton of H2O or 103 ton of H2.

Comparison of Doppler scintillation and in situ spacecraft plasma measurements of interplanetary disturbances

Abstract: Since 1979 the radio path of the Pioneer Venus orbiter (PVO) spacecraft has spent considerable time probing the near-Sun solar wind off the limbs of the Sun. On occasion, Helios 1 has also been in position above the Sun's limb at the same solar longitude to simultaneously observe in situ the solar wind plasma. These fortuitous circumstances, along with the availability of near-continuous measurements, have made it possible for the first time to carry out detailed comparisons between Doppler scintillation and in situ plasma measurements and to improve our understanding of Doppler scintillation transients. During a combined observing period of nearly 3 months in 1981–1982 near solar maximum, 22 transients were observed by PVO and 23 shocks were observed by Helios 1. On the basis of a comparison of mass flux density and rms Doppler scintillations, we find that at least 84% of the transients are shocks, while at least 90% of the shocks are transients. Hence there is a near one-to-one correspondence between transients and interplanetary shocks. Although the temporal profiles of Doppler scintillation and mass flux density are similar, the magnitudes of the Doppler scintillation transients may not simply reflect those of mass flux density. Only one pronounced solar wind event that was observed in the mass flux density measurements showed no signature in the scintillation data; field and particle measurements by Helios 1 suggest that it is a noncompressive density enhancement and/or a magnetic cloud. One of the scintillation transients that is not a fast-mode shock appears to correspond to a slow shock. However, when scintillations alone are available, slow shocks may be difficult to identify. Shock speeds based on transit times between the PVO radio scintillation path and the Helios 1 spacecraft are consistent with those from the in situ plasma measurements and indicate shock deceleration in essentially all cases. A significant consequence of this investigation is that Doppler scintillation measurements can now be used by themselves to detect and locate interplanetary shocks near the Sun with a relatively high degree of confidence and hence can be used to conduct useful correlative studies in the future with other solar and interplanetary observations.

Unitary scintillation detector and system

Abstract: The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations.

The dependence of the energy resolution of gas proportional scintillation counters on the scintillation region to photomultiplier distance

Abstract: The energy resolution for broad X-ray beams of gas proportional scintillation counters (GPSC) with medium to large size windows, parallel grids, and no focusing system is discussed. The variation of the pulse amplitude with the radial distance is calculated for several distances, d, (taken from the bottom of the scintillation region to the photomultiplier's photocathode), in the 0-50 mm range and compared with experimental results. It is shown that for a 2-in photomultiplier d distances from 10-20 mm, commonly used in the detector designs, represent a worst-case situation. The best design performance for GPSC is obtained bringing the scintillation region closer to the photomultiplier window. The advantages of this design consist not only in a light collection improvement but also, and more importantly, in a small dependence of the detector amplitude on the X-ray radial interaction position, a factor that limits the detector resolution for broad X-ray beams. >

ALTAIR VHF/UHF observations of multipath and backscatter enhancement

Abstract: During the Defense Nuclear Agency (DNA) PEAK (propagation effects assessment-Kwajalein) experiment in August 1988, the ALTAIR VHF/UHF wide bandwidth radar was used to track spherical satellites in low-earth orbit. The purpose of the experiment was to obtain radar data during the most severe natural propagation disturbances. The PEAK experiment was successful, giving many measurements of strong scintillation as well as the first measurements of frequency-selective fading on propagating radar pulses. Experimental results are used to demonstrate an enhancement, due to scattering, in the average received power that is observed during severe scintillation. The observed statistics of the enhancement are compared to analytic calculations using the Nakagami-m distribution with very good agreement. >

Scintillation properties of lead sulfate

Abstract: The authors report on the scintillation properties of lead sulfate (PbSO/sub 4/), a scintillator that shows promise as a high-energy photon detector. Its physical properties are well suited for gamma detection, as it has a density of 6.4 gm/cm/sup 3/ and a 1/e attenuation length for 511 keV photons of 1.2 cm, is not affected by air or moisture, and is cut and polished easily. In 99.998% pure PbSO/sub 4/ crystals at room temperature excited by 511 keV annihilation photons, the fluorescence decay lifetime contains significant fast components having 1.8 ns (5%) and 19 ns (36%) decay times, but with longer components having 95 ns (36%) and 425 ns (23%) decay times. The peak emission wavelength is 335 nm, which is transmitted by borosilicate glass windowed photomultiplier tubes. The total scintillation light output increases with decreasing temperature from 3200 photons/MeV at +45 degrees C to 4900 photons/MeV at room temperature (+25 infinity C) and 68500 photons/MeV at -145 degrees C. In an imperfect, 3-mm cube of a naturally occurring mineral form of PbSO/sub 4/, (anglesite) at room temperature, a 511 keV photopeak is seen with a total light output of 60% that of BGO. >

Beta scintillation probe

Abstract: A skin equivalent structure is formed from an aluminized polyester window and a scintillator. The scintillator is chosen to scintillate at a wavelength different from that of most Cerenkov light. The scintillator light travels through a light pipe and one or more filters to a photomultiplier tube. Beta particles reaching the scintillator provide light that results in an electrical output from the tube that corresponds to the skin beta dose rate. The filters are chosen to remove the Cerenkov light. In addition, the light pipe may also be chosen to attenuate the Cerenkov light.

Observations of quasi‐periodic scintillations and their possible relation to the dynamics of Es plasma blobs

Abstract: Quasi-periodic scintillations at a mid-latitude station, Wakkanai, Japan, are examined using 136-MHz geostationary satellite transmissions. Observations are compared with the ionospheric parameter obtained at the same station and random scintillation records. The results indicate that the quasi-periodic scintillations are most likely produced by plasma blobs within the sporadic E layers. Discussion focuses on characteristics of the ringing pattern which precedes and follows the primary deep fade-out, in field strength. In the majority of events the ringing pattern tends to develop after the distinct deep fade-out, i.e., the pattern is asymmetric. Quasi-periodic scintillation patterns are produced by the movement of plasma blobs in the case of geostationary satellite experiments. Thus the shape of the blob must be deformed so that a steep density gradient is attained on the backside. When the blob is highly deformed by the plasma instability which grows at the steep density gradient, burstlike random scintillations may be produced by the blob. 16 refs.

Asymptotic analysis of the flux fluctuations averaging and finite-size source scintillations in random media

Abstract: A complete set of asymptotes for the flux fluctuation variance or finite-size source scintillation index is obtained, starting from the path integral representation for a field in a random medium. A new approach to asymptotic analysis of related problems is introduced based on the concept of main/additional coherence channels expansion. This new technique was applied to asymptotic analysis of the quasi-plane wave variance.

Use of GSO for inelastic gamma-ray spectroscopy measurements in the borehole

Abstract: Gadolinium oxyorthosilicate (GSO) with its high density, high effective Z, fast decay time and good performance at high temperature, is the scintillation detector of choice for a new generation of neutron-induced, inelastic gamma-ray spectroscopy tools for borehole measurements, specifically aimed at measuring the carbon and oxygen content from the region surrounding the borehole. The ratio of the carbon and oxygen gamma-ray yields are transformed into formation oil saturation. To get the maximum benefit from GSO, the data acquisition, choice of materials, and measurement geometry were optimized for a small diameter tool at elevated temperatures and crystal characteristics. The large neutron cross section of the gadolinium in the scintillation crystal, its second decay constant, and the desired precision of the oil saturation measurement had important consequences in the tool design. >

Photodetector scintillator radiation imager having high efficiency light collection

Abstract: A radiation imager comprising an array of scintillator elements optically coupled to a photodetector array comprises a dielectric layer extending around at least the sidewalls of the scintillator elements, and preferably over the surface of the scintillator elements through which the incident radiation enters, and an optically reflective layer disposed over the dielectric layer. The dielectric layer has an optical index that is less than that of the scintillator material, and consequently light collection efficiency of the scintillator is improved as light photons generated in the scintillator reflected back into the scintillator both at the interface of the scintillator and the dielectric layer and at the optically reflective layer. A dome-shaped surface at the end of the scintillator element through which the incident radiation enters and an undulatory-shaped surface at the end of the scintillator which is optically coupled to the photodetectors further increase the light collection efficiency of the scintillator by reducing the number of photons that undergo total internal reflection in the scintillator.

Extended lifetime scintillation camera plate assembly

Abstract: A novel extended lifetime scintillation camera plate assembly and method for manufacture thereof is disclosed, the assembly comprising a body having a plurality of scintillating elements to receive the incoming radiation and produce light, and a plurality of light conducting elements coupled to the scintillating elements to receive and guide the light, and a frame which is sealed around the body by means of solder or laser weld joints thereby eliminating the need for temperature and moisture unstable epoxy resin sealing techniques.

Using scintillation at two wavelengths to measure path-averaged heat fluxes in free convection

Abstract: Local free convection scaling is one of the obvious triumphs of boundary-layer similarity theory. In free convection, there is no dynamic velocity scale; the sensible and latent heat fluxes, therefore, scale directly with the temperature and humidity structure parameters C t 2 and C q 2. By using scintillation to measure the refractive index structure parameter C n 2 at two electromagnetic (EM) wavelengths, we can obtain C t 2 and C q 2 and, thus, in effect, measure path-averaged values of the sensible and latent heat fluxes. Here I describe this so-called two-wavelength method for free convection, derive quantitative guidelines for optimizing the method, and evaluate its potential accuracy. I show that the two-wavelength method works best when one EM wavelength is in the visible or infrared region and the other is in the millimeter or radio region. When the Bowen ratio is between -5 and -0.1 or between 0.1 and 5, the expected accuracy of the measured fluxes is ±10–20% — typical of what is possible with eddy-correlation measurements. With the two-wavelength method, however, the fluxes represent spatial averages.

Monte Carlo optimization of depth-of-interaction resolution in PET crystals

Abstract: The light distribution along one edge of a positron emission tomography (PET) scintillation crystal was investigated with a Monte Carlo simulation. This position-dependent light can be used to measure the 511-keV photon interaction position in the crystal on an event-by-event basis, thus reducing radial elongation. The expectant full width at half maximum (FWHM) of the light distribution on the 3-mm*30-mm surface of a 3-mm*10-mm*30-mm bismuth germanate (BGO) crystal surrounded by a diffuse reflector was determined to be 3.0 mm. This light distribution does not change as the width (originally 3 mm) is varied from 1 to 6 mm, but decreases monotonically from 3.0 to 1.8 mm FWHM as the height (originally 10 mm) is reduced to 3 mm. Other geometrical modifications were simulated, including numerous corner reflectors on the opposing 3-mm *30-mm surface, which reduced the FWHM to 2.4 mm. The response of a dual-wedge photodiode combined with the predicted light distribution for the 3-mm*10-mm*30-mm BGO scintillation crystal results in an expected depth of interaction resolution of 7.5 mm FWHM. >

Timing properties of long scintillation counters based on scintillating fibers

Abstract: The light output and timing characteristics of a scintillation counter constructed of plastic scintillating fibers are compared to those of a counter with identical transverse cross section of 2 cm × 3 cm made of bulk scintillator. It is shown that the timing resolution at long distances is better for the fiber than for the bulk scintillator. The improvement is a factor of 1.8 at a distance of 2 m from the phototube.

Method for manufacturing a high resolution structured x-ray detector

Abstract: A method of producing scintillation phosphor X-ray detector arrays using k materials and repetitive manufacturing techniques. The structures formed by this method may be used to detect x-rays, charged particles and neutral particles by converting the incident radiation into optical radiation. Detectors manufactured by the methods of this invention will produce better x-ray images and reduce the amount of radiation a medical patient or industrial target is subjected to.

Determination of time-varying 222Rn concentrations using flow-through scintillation flasks.

Abstract: This paper describes a method to obtain time-varying 222Rn concentrations from the series of gross alpha measurements recorded with a flow-through scintillation detector. The continuous input of 222Rn into the detector is treated as a series of independent pulses. The response of the detector to a single pulse containing 222Rn can be measured in the laboratory and is used to determine a normalized detector response function (NDRF). The NDRF contains information on the combined effects of detector design, operating parameters, and the presence of 222Rn progeny. The estimation of individual plate-out or counting efficiencies is not needed, as they are appropriately included in the NDRF. The equation describing the response function can be inverted to yield the actual 222Rn concentration in terms of detector output. The technique was applied to actual indoor monitoring data and the results presented.

Scintillating plastic optical fiber radiation detectors in high-energy particle physics

Abstract: We describe the application of scintillating optical fiber in instrumentation for high energy particle physics. The basic physics of the scintillation process in polymers is discussed first and then we outline the fundamentals of scintillating fiber technology. Fiber performance, optimization, and characterization measurements are given. Detector applications in the areas of particle tracking and particle energy determination are then described. 13 refs., 12 figs.

Development and characterization of new scintillation materials for fiber tracking and calorimetry

Abstract: Several polystyrene-based scintillators have been prepared in the Chemistry Facility of Fermi National Accelerator Laboratory and their light yield, fluorescence, and transmittance have been studied. In addition, emission time distributions were measured and the decay time constants were determined. A radiation damage study was performed in which the samples were irradiated to a total dose of 10 Mrad. After annealing, the intrinsic light yield of the most radiation-hard scintillators had not changed significantly.