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Error analysis for fast scintillator-based ICF burn history measurements

Description: Plastic scintillator material acts as a neutron-to-light converter in instruments that make ICF burn history measurements. Light output for a detected neutron has a fast rise time (420 ps) and a relatively long decay constant (1.2 ns). For a burst of neutrons whose duration is much shorter than the decay constant, instantaneous light output is approximately proportional to the integral of the neutron interaction rate with the scintillator material. Burn history is obtained by deconvolving the exponential decay from the recorded signal.
Date: July 6, 1998
Creator: Lerche, R A & Ognibene, T J
Partner: UNT Libraries Government Documents Department

Smart Surfaces: New Coatings & Paints with Radiation Detection Functionality

Description: Paints are being developed and tested that might ultimately be able to detect radiological agents in the environment by incorporating special pigments into an organic polymeric binder that can be applied as a paint or coatings. These paints detect radioactive sources and contaminants with inorganic or organic scintillation or thermo-luminescent pigments, which are selected based upon the radiation ({alpha}, {beta}, {gamma} or n) to be detected, and are shown in Figure 1.
Date: March 12, 2007
Creator: Farmer, J & Choi, J
Partner: UNT Libraries Government Documents Department

LOGARITHMIC SPIRAL LIGHT PIPE FOR SCINTILLATORS

Description: A prccedure is described for designing and making logarithmic spiral light pipes which are to be used in coupling scintillators to photomultipliers in cases where the scintillator must be placed in a strong magnetic field. (C.J.G.)
Date: August 1, 1960
Creator: Kaiser, W.C.; MacKay, A.J. & Managan, W.W.
Partner: UNT Libraries Government Documents Department

Signal Analysis for Radiation Event Identification

Description: The method of digitizing the scintillation output signals from a lithiated sol-gel based glass is described. The design considerations for using the lithiated scintillator for the detection of Special Nuclear Material (SNM) is presented.
Date: December 30, 2004
Creator: Wallace, Steven A.
Partner: UNT Libraries Government Documents Department

A MEASUREMENT OF THE POSITIVE pi- Mu DECAY LIFETIME

Description: The lifetime for the decay of a {pi} meson into {mu} meson and neutral particle was first measured by Richardson and later by Martinelli and Panofsky. The method was the same in both cases: The fraction of {pi} mesons surviving various times of flight is measured by placing photographic detectors at various path lengths from the target. In the experiment reported here we observe the time lag between the two bursts of fluorescence due to mesons decaying in a scintillation crystal. The first burst is due to the stopping of the entering {pi} meson, the second to the {mu}-meson. As is shown in Fig. 1, a particle penetrating the first and into the second crystal starts the sweep (10{sup -8} sec/mm) of an oscilloscope. The pulses in the second crystal are delayed 0.5 x 10{sup -6} sec to allow the sweep to start and brighten and are then photographed. If the responsible particle is a {pi}{sup +} meson which stops in the crystal, it undergoes {pi}-{mu} decay and two pulses appear on the trace. The {mu}{sup +} meson has a range of only 2 mm in the crystal. If its decay electron is detected some time (.5-2.5 x 10{sup -6} sec) later; a neon light flashes and is photographed together with the scope trace. Only such marked traces are measured. Of these marked traces, 650 or roughly one-half, show the two pulses of the {pi}-{mu} event. Five percent are calculated to be due to random delayed coincidences, and another 3 percent due to {pi} mesons which have decayed in flight and come to rest in the second crystal as {mu} mesons. The remaining traces are due to {pi}{mu} decays which are too fast to be resolved. The sweep speed of the oscilloscope is calibrated periodically with an oscillator of known ...
Date: May 10, 1950
Creator: Chamberlain, O.; Mozely, R.F.; Steinberger, J. & Wiegand, C.
Partner: UNT Libraries Government Documents Department

Room-temperature scintillation properties of cerium-doped REOX (RE=Y, La, Gd, and Lu; X=F, Cl, Br, and I)

Description: The scintillation properties of cerium-doped oxyhalides following the general formula REOX (RE=Y, La, Gd, and Lu; X=F, Cl, Br, and I) are reported. These materials were synthesized under dry conditions as microcrystalline powders from conventional solid state reactions. The room temperature X-ray excited emission and scintillation decay curves were measured and analyzed for each material. Additionally, the hygroscopic nature of the oxychlorides and oxybromides was compared to that of their corresponding rare earth halides. The yttrium, lanthanum, and gadolinium oxychlorides, and all of the oxybromides and oxyiodides are found to be activated by Ce{sup 3+}. GdOBr doped with 0.5% Ce{sup 3+} has the highest light output with a relative luminosity of about one-half that of LaBr{sub 3}: Ce{sup 3+}. It displays a single exponential decay of 30 ns.
Date: December 10, 2010
Creator: Eagleman, Yetta; Bourret-Courchesne, Edith & Derenzo, Stephen
Partner: UNT Libraries Government Documents Department

First study of nano-composite scintillators under alpha irradiation

Description: We demonstrate that nano-composite materials based on semiconductor quantum dots have great potential for radiation detection via scintillation. While quantum dots and laser dyes both emit in the visible range at room temperature, the Stokes shift of the dyes is significantly larger. The scintillation output of both systems was studied under alpha irradiation and interpreted using a combination of energy-loss and photon transport Monte Carlo simulation models. The comparison of the two systems, which allows the quantification of the role played by the Stokes shift in the scintillation output, opens up exciting possibilities for a new class of scintillators that would take advantage of the limitless assembly of nano-crystals in large, transparent, and sturdy matrices.
Date: June 1, 2005
Creator: Letant, S & Wang, T
Partner: UNT Libraries Government Documents Department

Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter

Description: We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al.. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well-described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.
Date: February 14, 2011
Creator: Sorensen, P & Dahl, C E
Partner: UNT Libraries Government Documents Department

Measurements of NaI(Tl) electron response: comparison of different samples

Description: This paper measures the sample to sample variation in the light yield proportionality of NaI(Tl), and so explores whether this is an invariant characteristic of the material or whether it depends on the chemical and physical properties of the tested samples. We report on the electron response of nine crystals of NaI(Tl), differing in shape, volume, age, manufacturer and quality. The proportionality has been measured at the SLYNCI facility in the energy range between 3.5 to 460 keV. We observe that while samples produced by the same manufacturer at approximately the same time have virtually identical electron response curves, there are significant sample to sample variations among crystals produced by different manufacturers or at different times. In an effort to correlate changes in the electron response with details of the scintillation mechanism, we characterized other scintillation properties, including the gamma response and the x-ray excited emission spectra and decay times, for the nine crystals. While sample to sample differences in these crystals were observed, we have been unable to identify the underlying fundamental mechanisms that are responsible for these differences.
Date: December 10, 2008
Creator: Hull, Giulia; Choong, Woon-Seng; Moses, William W.; Bizarri, Gregory; Valentine, John D.; Payne, Stephen A. et al.
Partner: UNT Libraries Government Documents Department

Study of New Muon Energy Detector at Tevatron Muon Beam Line

Description: A new method for the energy determination of Tev muons will be studied at Tevatron beam line. More than 200 layers scintillation shower detector is located in front of Tevatron muon experimental group (E-665). The energy resolution of small shower detector induced by muons will be experimentally obtained.
Date: January 1, 1986
Creator: Mitsui, K.; Muraki, Y.; Okada, A.; Ohashi, Y.; U., /Tokyo; Matsumoto, S. et al.
Partner: UNT Libraries Government Documents Department

VARIANCE IN SCINTILLATOR LIGHT COLLECTION

Description: A Monte-Carlo program for the GEORGE'' Computer at Argonne National Laboratory was used to compute the average path length and number of diffuse reilections of a light ray originating at a given point in a cylinder before it is absorbed in a black'' concentric circle in the bottom of the cylinder. The variance of these numbers is estimated and indicates light-trapping effects. Total internal reflection at the exit ( black'') interface is included. The average number of refiections increases rapidly as the crystal length exceeds one diameter. (auth)
Date: June 1, 1963
Creator: Sinnott, G.A. & Managan, W.A.
Partner: UNT Libraries Government Documents Department

HANDBOOK FOR THE NANO-SECOND ELECTRON ACCELERATOR (NSEA)

Description: As an aid to prospective users of the device, the electron accelerator, the detection system, and the readout equipment are described; and the operational procedures followed are explained. Maintenance instructions are also given, as are diagrams of many components. The apparatus was designed mainly for studying scintillation decay times in the nsec region. (D.C.W.)
Date: March 1, 1963
Creator: Mroz, E.A.; Buck, W.L.; Swank, R.K. & Phillips, H.B.
Partner: UNT Libraries Government Documents Department

A study on dual readout crystal calorimeter for hadron and jet energy measurement at a future lepton collider

Description: Studies of requirements and specifications of crystals are necessary to develop a new generation of crystals for dual readout crystal hadron or total absorption calorimeter. This is a short and basic study of the characteristics and hadron energy measurement of PbWO4 and BGO crystals for scintillation and Cerenkov Dual Readout hadron calorimeter.
Date: January 1, 2010
Creator: Yeh, G.P.
Partner: UNT Libraries Government Documents Department

Evaluation of production samples of the scintillators LaBr3:Ce and LaCl3:Ce

Description: We report on the evaluation of the performance of two recently developed scintillator materials, LaCl{sub 3}:Ce and LaBr{sub 3}:Ce, at the task of gamma ray spectroscopy. Their performance is compared to a standard scintillator used for gamma ray spectroscopy--a 25 mm diameter 25 mm tall cylinder of NaI:Tl. We measure the pulse height, energy resolution, and full-energy efficiency of production LaBr{sub 3}:Ce and LaCl{sub 3}:Ce scintillation crystals of different sizes and geometries for a variety of gamma-ray energies. Using production rather than specially selected crystals will establish whether immediate large-scale use is feasible. The crystal is excited by gamma rays from one of six isotopic sources ({sup 125}I, {sup 241}Am, {sup 57}Co, {sup 22}Na, {sup 137}Cs, and {sup 60}Co) placed 15 cm away from the scintillator. Our measurements show that both LaCl{sub 3} and LaBr{sub 3} outperform NaI:Tl in almost all cases. They outperform NaI:Tl at all energies for the photopeak fraction and counting rate measurements, and for energy resolution at higher energies (above 200 keV for LaCl{sub 3} and 75 keV for LaBr{sub 3}). The performance of production crystals is excellent and these scintillators should be considered for immediate use in systems where stopping power and energy resolution are crucial.
Date: September 15, 2005
Creator: Choong, Woon-Seng; Derenzo, Stephen E. & Moses, William W.
Partner: UNT Libraries Government Documents Department

A Method for Concurrent and Continuous Measurement of Rn-222 and Rn-220 Using Scintillation Cells

Description: A method is described for the continuous and simultaneous measurement of both {sup 220}Rn and {sup 222}Rn in air. Two scintillation flasks are arranged in a serial configuration and the concentrations of {sup 222}Rn and {sup 220}Rn are determined by making use of the difference between the half-lives of the two radon isotopes. The method was developed for directly measuring {sup 220}Rn in occupied areas where fuel materials containing {sup 228}Th were being used, but could also be useful for other applications. Since {sup 222}Rn is usually present from either naturally occurring materials or due to the presence of process material, the method was designed to allow measurement of the two isotopes at coincident times. The method is discussed for counting equipment using scintillation cells, but the approach would also be directly applicable for any type of pulse-counting radon monitoring equipment such as pulse-ion chambers. Although intermittent measurements with decay correction could be performed using a single detector, the use of two cells allows continuous monitoring and a higher degree of detection sensitivity. The approach makes use of isotope-independent calibration factors and could therefore easily be modified for use with a single detector when only one of the radon isotopes is expected to be present.
Date: January 31, 2002
Creator: Coleman, R.L.
Partner: UNT Libraries Government Documents Department

Scintillator manufacture at Fermilab

Description: A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.
Date: August 1, 1998
Creator: Mellott, K.; Bross, A. & Pla-Dalmau, A.
Partner: UNT Libraries Government Documents Department

POTENTIAL IMPACT OF TANK F FLUSH SOLUTION ON H-CANYON EVAPORATOR OPERATION

Description: Previous chemical analysis of a sample from the liquid heel found in Tank F of the High Activity Drain (HAD) system in F/H laboratory revealed the presence of n-paraffin, tributyl phosphate (TBP), Modifier from the Modular Caustic-Side Solvent Extraction Unit (MCU) process and a vinyl ester resin that is very similar to the protective lining on Tank F. Subsequent analyses detected the presence of a small amount of diisopropylnaphthalene (DIN) (major component of Ultima Gold{trademark} AB liquid scintillation cocktail). Indications are that both vinyl ester resin and DIN are present in small amounts in the flush solution. The flush solution currently in the LR-56S trailer likely has an emulsion which is believed to contain a mixture of the reported organic species dominated by TBP. An acid treatment similar to that proposed to clear the HAD tank heel in F/H laboratory was found to allow separation of an organic phase from the cloudy sample tested by SRNL. Mixing of that clear sample did re-introduce some cloudiness that did not immediately clear but that cloudiness is attributed to the DIN in the matrix. An organic phase does quickly separate from the cloudy matrix allowing separation by a box decanter in H-Canyon prior to transfer to the evaporator feed tank. This separation should proceed normally as long as the emulsion is broken-up by acidification.
Date: September 13, 2010
Creator: Kyser, E.; Fondeur, F. & Fink, S.
Partner: UNT Libraries Government Documents Department

IBM-704 CODES FOR PREDICTING THE RESPONSE OF GAMMA-RAY SCINTILLATION COUNTERS

Description: A manual for Operating several codes for an IBM-704 to calculate the pulse-heat response functions for gamma-ray scintiliation counters is presented. Using . the Monte Carlo method of computation, the codes will calculate the pulse-heat response function of xylene, Csl, or Nal counters of various geometrical configurations with cylindrical symmetry. Various monoenergetic source configurations are possible with a maximum source energy of 10.22 Mev. (auth)
Date: May 19, 1960
Creator: Zerby, C D & Moran, H S
Partner: UNT Libraries Government Documents Department

An Automatic Lithium Drifting Apparatus for Silicon and Germanium Detectors

Description: Drifting a thick lithium-drifted counter (silicon and germanium) is a time-consuming operation that frequently results in a poor device, owing to inadequate knowledge of progress of the drifting operation. The drifting apparatus described here automatically controls the temperature of the detector that is being drifted to maintain the leakage current at a preselected value. While drifting proceeds, a continuous measurement is made of the distance of the lithium-drifted region from the opposite face of the wafer. When the drifted region reaches 30 mil or less from the back of the wafer a meter indicates the thickness of the undrifted region and, when this thickness falls below a preselected value, the temperature of the detector is automatically reduced to room temperature. The need for constant supervision of the drifting operation is thereby eliminated, and reliance on theoretical drift-rate calculations to predict the drift-through time is avoided. The technique has been applied to the manufacture of lithium-drifted silicon detectors with excellent results. The application of the technique to lithium-drifted germanium {gamma} detectors is also discussed briefly.
Date: February 8, 1964
Creator: Goulding, Fred S. & Hansen, W. L.
Partner: UNT Libraries Government Documents Department

FY05 LDRD Final ReportNanomaterials for Radiation Detection

Description: We have demonstrated that it is possible to enhance current radiation detection capability by manipulating the materials at the nano level. Fabrication of three-dimensional (3-D) nanomaterial composite for radiation detection has great potential benefits over current semiconductor- and scintillation-based technologies because of the precise control of material-radiation interaction and modulation of signal output. It is also a significant leap beyond current 2-D nanotechnology. Moreover, since we are building the materials using a combination of top-down and bottom-up approaches, this strategy to make radiation detection materials can provide significant improvement to radiation-detection technologies, which are currently based on difficult-to-control bulk crystal growth techniques. We are applying this strategy to tackle two important areas in radiation detection: gamma-rays and neutrons. In gamma-ray detection, our first goal is to employ nanomaterials in the form of quantum-dot-based mixed matrices or nanoporous semiconductors to achieve scintillation output several times over that from NaI(Tl) crystals. In neutron detection, we are constructing a 3-D structure using a doped nanowire ''forest'' supported by a boron matrix and evaluating the detection efficiency of different device geometry with simulation.
Date: February 6, 2006
Creator: Wang, T F; Letant, S E; Nikolic, R J & Chueng, C L
Partner: UNT Libraries Government Documents Department

Crystal growth and scintillation properties of strontium iodide scintillators

Description: Single crystals of SrI{sub 2}:Eu and SrI{sub 2}:Ce/Na were grown from anhydrous iodides by the vertical Bridgman technique in evacuated silica ampoules. Growth rates were of the order of 5-30 mm/day. Radioluminescence spectra of SrI{sub 2}:Eu and SrI{sub 2}:Ce/Na exhibit a broad band due to Eu{sup 2+} and Ce{sup 3+} emission, respectively. The maximum in the luminescence spectrum of SrI{sub 2}:Eu is found at 435 nm. The spectrum of SrI{sub 2}:Ce/Na exhibits a doublet peaking at 404 and 435 nm attributed to Ce{sup 3+} emission, while additional impurity - or defected - related emission is present at approximately 525 nm. The strontium iodide scintillators show very high light yields of up to 120,000 photons/MeV, have energy resolutions down to 3% at 662 keV (Full Width Half Maximum) and exhibit excellent light yield proportionality with a standard deviation of less than 5% between 6 and 460 keV.
Date: June 1, 2009
Creator: van Loef, Edgar; Wilson, Cody; Cherepy, Nerine; Payne, Steven; Choong, Woon-Seng; Moses, William W. et al.
Partner: UNT Libraries Government Documents Department

ACID EVAPORATION OF ULTIMA GOLD TM AB LIQUID SCINTILLATION COCKTAIL RESIDUE

Description: Prior analyses of samples from the F/H Lab solutions showed the presence of diisopropylnapthalene (DIN), a major component of Ultima Gold{trademark} AB liquid scintillation cocktail (LSC). These solutions are processed through H-Canyon Tank 10.5 and ultimately through the 17.8E evaporator. Similar solutions originated in SRNL streams sent to the same H Canyon tanks. This study examined whether the presence of these organics poses a process-significant hazard for the evaporator. Evaporation and calorimetry testing of surrogate samples containing 2000 ppm of Ultima Gold{trademark} AB LSC in 8 M nitric acid have been completed. These experiments showed that although reactions between nitric acid and the organic components do occur, they do not appear to pose a significant hazard for runaway reactions or generation of energetic compounds in canyon evaporators. The amount of off-gas generated was relatively modest and appeared to be well within the venting capacity of the H-Canyon evaporators. A significant fraction of the organic components likely survives the evaporation process primarily as non-volatile components that are not expected to represent any new process concerns during downstream operations such as neutralization. Laboratory Waste solutions containing minor amounts of DIN can be safely received, stored, transferred, and processed through the canyon waste evaporator.
Date: December 21, 2011
Creator: Kyser, E.; Fondeur, F. & Crump, S.
Partner: UNT Libraries Government Documents Department

Scintillators with potential to supersede lanthanum bromide

Description: New scintillators for high-resolution gamma ray spectroscopy have been identified, grown and characterized. Our development efforts have focused on two classes of high light yield materials: Europium-doped alkaline earth halides and Cerium-doped garnets. Of the halide single crystals we have grown by the Bridgman method - SrI{sub 2}, CaI{sub 2}, SrBr{sub 2}, BaI{sub 2} and BaBr{sub 2} - SrI{sub 2} is the most promising. SrI{sub 2}(Eu) emits into the Eu{sup 2+} band, centered at 435 nm, with a decay time of 1.2 {micro}s and a light yield of up to 115,000 photons/MeV. It offers energy resolution better than 3% FWHM at 662 keV, and exhibits excellent light yield proportionality. Transparent ceramics fabrication allows production of Gadolinium- and Terbium-based garnets which are not growable by melt techniques due to phase instabilities. While scintillation light yields of Cerium-doped ceramic garnets are high, light yield non-proportionality and slow decay components appear to limit their prospects for high energy resolution. We are developing an understanding of the mechanisms underlying energy dependent scintillation light yield non-proportionality and how it affects energy resolution. We have also identified aspects of optical design that can be optimized to enhance energy resolution.
Date: June 1, 2009
Creator: Cherepy, Nerine; Payne, Steven; Aszatlos, Steve; Hull, Giulia; Kuntz, J.; Niedermayr, Tom et al.
Partner: UNT Libraries Government Documents Department