Virtual point detector: On the interpolation and extrapolation of scintillation detectors counting efficiencies

International Nuclear Information System (INIS)

Presler, Oren; German, Uzi; Pushkarsky, Vitaly; Alfassi, Zeev B.

2006-01-01

The concept of transforming the detector volume to a virtual point detector, in order to facilitate efficiency evaluations for different source locations, was proposed in the past for HPGe and Ge(Li) detectors. The validity of this model for NaI(Tl) and BGO scintillation detectors was studied in the present work. It was found that for both scintillation detectors, the point detector model does not seem to fit too well to the experimental data, for the whole range of source-to-detector distances; however, for source-to-detector cap distances larger than 4 cm, the accuracy was found to be high. A two-parameter polynomial expression describing the dependence of the normalized count rate versus the source-to-detector distance was fitted to the experimental data. For this fit, the maximum deviations are up to about 12%. These deviations are much smaller than the values obtained by applying the virtual point concept, even for distances greater than 4 cm, thus the polynomial fitting is to be preferred for scintillation detectors

Problems associated with scintillation counting of NaH14CO3 and gel suspension counting of Ba14CO3

International Nuclear Information System (INIS)

MacRae, J.C.; Wilson, S.

1978-01-01

Liquid NaH 14 CO 3 was assayed in emulsion-type (NE260 and Unisolve) and dioxan-based (NE250) scintillation cocktails contained in glass or polyethylene vials kept at 2 0 or 24-30 0 C. Different particle size ranges of standard Ba 14 CO 3 were assayed by gel suspension counting in Cabosil scintillation cocktail and in NE260 following solubilisation in EDTA-tetrasodium salt. Initial detectable activities of NaH 14 CO 3 in glass and polyethylene vials in NE250, NE260 and Unisolve were 97 and 96, 68 and 83, 71 and 89% of the true value respectively. Subsequent losses of activity over 7 days with the emulsion-type scintillators was greater from the polyethylene vials. Addition of phenylethylamine to the NE260 and Unisolve cocktails gave the true activity levels for all vials with no loss of activity over 6 days. When different particle size ranges of Standard Ba 14 CO 3 were suspended in Cabosil scintillation cocktail there was considerable variation in counting efficiency (77-88%) with little relationship between particle size and counting efficiency. The relationship between counting efficiency and channels ratio was not sufficiently precise for predictive purposes. Solubilisation of Ba 14 CO 3 in EDTA-tetrasodium salt gave similar counting efficiency and channels ratio values for all samples. (U.K.)

Gross alpha/beta analyses in water by liquid scintillation counting

International Nuclear Information System (INIS)

Wong, C.T.; Lawrence Livermore National Laboratory, CA; Soliman, V.M.; Perera, S.K.

2005-01-01

The standard procedure for analyzing gross alpha and gross beta in water is evaporation of the sample and radioactivity determination of the resultant solids by proportional counting. This technique lacks precision, and lacks sensitivity for samples with high total dissolved solids. Additionally, the analytical results are dependent on the choice of radionuclide calibration standard and the sample matrix. Direct analysis by liquid scintillation counting has the advantages of high counting efficiencies and minimal sample preparation time. However, due to the small sample aliquants used for analysis, long count times are necessary to reach required detection limits. The procedure proposed consists of evaporating a sample aliquant to dryness, dissolving the resultant solids in a small volume of dilute acid, followed by liquid scintillation counting to determine radioactivity. This procedure can handle sample aliquants containing up to 500 mg of dissolved solids. Various acids, scintillation cocktail mixtures, instrument discriminator settings, and regions of interest (ROI) were evaluated to determine optimum counting conditions. Precision is improved and matrix effects are reduced as compared to proportional counting. Tests indicate that this is a viable alternative to proportional counting for gross alpha and gross beta analyses of water samples. (author)

Method for determining efficiency in a liquid scintillation system

International Nuclear Information System (INIS)

Laney, B.H.

1975-01-01

This invention relates to a method of counting radioactive events in a liquid scintillation radiation detecting and counting apparatus by utilizing pulses generated by a photomultiplying means resulting from scintillations caused by radioactive events. A counting efficiency value is assigned to each pulse generated in the photomultiplying means according to the height of the pulse. The numerical inverse of each assigned counting efficiency value is determined and each numerical inverse is recorded as an actual number of radioactive events with each having a pulse height identical to that of the corresponding pulse generated in the photomultiplying means. (Patent Office Record)

Liquid scintillation, counting, and compositions

International Nuclear Information System (INIS)

Sena, E.A.; Tolbert, B.M.; Sutula, C.L.

1975-01-01

The emissions of radioactive isotopes in both aqueous and organic samples can be measured by liquid scintillation counting in micellar systems. The micellar systems are made up of scintillation solvent, scintillation solute and a mixture of surfactants, preferably at least one of which is relatively oil-soluble water-insoluble and another which is relatively water-soluble oil-insoluble

Liquid scintillation counting system with automatic gain correction

International Nuclear Information System (INIS)

Frank, R.B.

1976-01-01

An automatic liquid scintillation counting apparatus is described including a scintillating medium in the elevator ram of the sample changing apparatus. An appropriate source of radiation, which may be the external source for standardizing samples, produces reference scintillations in the scintillating medium which may be used for correction of the gain of the counting system

Determining random counts in liquid scintillation counting

International Nuclear Information System (INIS)

Horrocks, D.L.

1979-01-01

During measurements involving coincidence counting techniques, errors can arise due to the detection of chance or random coincidences in the multiple detectors used. A method and the electronic circuits necessary are here described for eliminating this source of error in liquid scintillation detectors used in coincidence counting. (UK)

Counting efficiency for liquid scintillator systems with a single multiplier phototube; Eficiencia de recuento en espectrometros de centelleo con un solo fotomultiplicador

Energy Technology Data Exchange (ETDEWEB)

Grau Malonda, A; Garcia-Torano, E

1984-07-01

In this paper counting efficiency as a function of a free parameter (the figure of merit) has been computed. The results are applicable to liquid scintillator systems with a single multiplier phototube. Tables of counting efficiency for 62 pure beta emitters are given for figures of merit in the range 0.25 to 50. (Author) 16 refs.

Current status of liquid scintillation counting

International Nuclear Information System (INIS)

Klingler, G.W.

1981-01-01

Scintillation counting of alpha particles has been used since the turn of the century. The advent of pulse shape discrimination has made this method of detection accurate and reliable. The history, concepts and development of scintillation counting and pulse shape discrimination are discussed. A brief look at the ongoing work in the consolidation of components now used for pulse shape discrimination is included

Calculating concentration of inhaled radiolabeled particles from external gamma counting: External counting efficiency and attenuation coefficient of thorax

International Nuclear Information System (INIS)

Langenback, E.G.; Foster, W.M.; Bergofsky, E.H.

1989-01-01

We determined the overall external counting efficiency of radiolabeled particles deposited in the sheep lung. This efficiency permits the noninvasive calculation of the number of particles and microcuries from gamma-scintillation lung images of the live sheep. Additionally, we have calculated the attenuation of gamma radiation (120 keV) by the posterior chest wall and the gamma-scintillation camera collection efficiency of radiation emitted from the lung. Four methods were employed in our experiments: (1) by light microscopic counting of discrete carbonized polystyrene particles with a count median diameter (CMD) of 2.85 microns and tagged with cobalt-57, we delineated a linear relationship between the number of particles and the emitted counts per minute (cpm) detected by well scintillation counting; (2) from this conversion relationship we determined the number of particles inhaled and deposited in the lungs by scintillation counting fragments of dissected lung at autopsy; (3) we defined a linear association between the number of particles or microcuries contained in the lung and the emitted radiation as cpm detected by a gamma scintillation camera in the live sheep prior to autopsy; and (4) we compared the emitted radiation from the lungs of the live sheep to that of whole excised lungs in order to calculate the attenuation coefficient (ac) of the chest wall. The mean external counting efficiency was 4.00 X 10(4) particles/cpm (5.1 X 10(-3) microCi/cpm), the camera collection efficiency was 1 cpm/10(4) disintegrations per minute (dpm), and the ac had a mean of 0.178/cm. The external counting efficiency remained relatively constant over a range of particles and microcuries, permitting a more general use of this ratio to estimate number of particles or microcuries depositing after inhalation in a large mammalian lung if a similarly collimated gamma camera system is used

Triton X-100 as a complete liquid scintillation cocktail for counting aqueous solutions and ionic nutrient salts

International Nuclear Information System (INIS)

Reed, D.W.

1984-01-01

Triton X-100, used alone, was found to act as a complete liquid scintillation cocktail. Triton X-100 acted as a scintillator and the effect was not due to Cerenkov radiation. A variety of other commercially available surfactants also acted as scintillators, but with different levels of efficiency. Triton X-100/water combinations were suitable for counting aqueous solutions of 33 P and 86 Rb and the count rate was stable over extended periods of time. Triton X-100/toluene combinations also yielded high counting efficiencies. Triton X-100 was more sensitive to quenching than standard cocktails containing fluors. (author)

Enhanced counting efficiency of Cerenkov radiation from bismuth-210

International Nuclear Information System (INIS)

Peck, G.A.; Smith, J.D.

1998-01-01

This paper describes the measurement of 210 Bi by Cerenkov counting in a commercial liquid scintillation counter. The counting efficiency in water is 0.17 counts per second per Becquerel (17%). When the enhancers Triton X-100 (15% v/v) and sodium salicylate (1% m/v) are added to the solution the counting efficiency for 210 Bi increases from 17% to 75%. The 210 Po daughter of 210 Bi causes interference of 0.85 counts per second per Becquerel in the presence of the enhancers but not in water. When 210 Bi and 210 Po are present in secular equilibrium the total counting efficiency is 160%. When 210 Bi and 210 Po are not in secular equilibrium the 210 Po can be removed immediately before counting by plating onto silver foil. The use of the enhancers gives a substantial increase in counting efficiency compared to counting in water. Compared with solutions used in liquid scintillation counting the enhancer solution is inexpensive and can be disposed of without environmental hazard. (author)

Use of pliable bags in liquid scintillation counting

International Nuclear Information System (INIS)

Simonnet, G.; Jacquet, M.A.; Sharif, A.; Engler, R.

1981-01-01

Pliable plastic bags have been used to replace glass or plastic vials for liquid scintillation counting. The two major advantages of this method are the lower cost of the plastic bags and the fact that, per sample, the radioactive waste is significantly reduced. The following parameters have been checked: the impermeability of the bags to various scintillator mixtures and the fact that neither the irregular shape of the bags nor their position in the counting chamber had any effect on the results of the counting. The latter was also constant with time, at least over a period of 10 days. The technique has been used to count the radioactivity of 3 H-DNA precipitates prepared from bacteria and lymphocytes and deposited on filters impregnated with only 200 μl scintillator. It is a method that can be applied to the counting of any samples deposited on filters and insoluble in scintillator. (author)

Study on quench effects in liquid scintillation counting during tritium measurements

International Nuclear Information System (INIS)

Ivana Jakonic; Jovana Nikolov; Natasa Todorovic; Miroslav Veskovic; Branislava Tenjovic

2014-01-01

Quench effects can cause a serious reduction in counting efficiency for a given sample/cocktail mixture in liquid scintillation counting (LSC) experiments. This paper presents a simple experiment performed in order to test the influence of quenching on the LSC efficiency of 3 H. The aim of this study was to investigate the behavior of several quench agents with different quench strengths (nitromethane, nitric acid, acetone, dimethyl-sulfoxide) added in different amounts to tritiated water in order to obtain standard sets for quench calibration curves. The OptiPhase HiSafe 2 and OptiPhase HiSafe 3 scintillation cocktails were used in this study in order to compare their quench resistance. Measurements were performed using a low-level LS counter (Wallac, Quantulus 1220). (author)

Influence of atomic and nuclear constants on the counting efficiency for 55Fe in liquid scintillators

International Nuclear Information System (INIS)

Fernandez, A.; Grau, A.; Arcos, J. M. los

1985-01-01

In this paper one considers the influence of the different parameters on the determination of the uncertainty of the detection efficiency for 55 F e when the counting technique of liquid scintillation is applied. The following parameters are considered: the relative probabilities of X and Auger emission so as their corresponding energies, the fluorescence yields W K and W L , and the non-interaction probabilities of the emitted X photons. (Author) 11 refs

Method for determining efficiency in a liquid scintillation system

International Nuclear Information System (INIS)

Laney, B.H.

1975-01-01

In a liquid scintillation system utilizing plural photomultiplyier means, a method for determining efficiency of coincident pulse detection. Various incremental counting efficiency levels are associated with asymptotic functions in a two dimension matrix in which the abscissa and ordinate correspond to the pulse heights of each of a pair of coincident pulses from different photomultiplier means. An efficiency determining point is located in the matrix based on the sum of the pulse heights of each of the coincident pulses as well as on the amplitude of the smallest pulse of the coincident pulses. The single counting efficiency determining point is recorded as the level of efficiency at which the photomultiplier means detect scintillations that generate coincident pulses having pulse heights equal to those recorded. (Patent Office Record)

Accurate disintegration-rate measurement of 55Fe by liquid scintillation counting

International Nuclear Information System (INIS)

Steyn, J.; Oberholzer, P.; Botha, S.M.

1979-01-01

A method involving liquid scintillation counting is described for the accurate measurement of disintegration rate of 55 Fe. The method is based on the use of calculated efficiency functions together with either of the nuclides 54 Mn and 51 Cr as internal standards for measurement of counting efficiencies by coincidence counting. The method was used by the NAC during a recent international intercomparison of radioactivity measurements, and a summary of the results obtained by nine participating laboratories is presented. A spread in results of several percent is evident [af

On the use of liquid scintillation counting of 51Cr and 14C in the twin tracer method of measuring assimilation efficiency

International Nuclear Information System (INIS)

Cammen, L.M.

1977-01-01

Calow and Fletcher (1972) calculated assimilation efficiency from the ratio of an assimilated radiotracer ( 14 C) to a non-assimilated tracer ( 51 Cr) in food and feces. Wightman (1975) improved the efficiency of their technique by using liquid scintillation to count both isotopes simultaneously, but stated incorrectly that it was not necessary to convert count per minute (CPM) to disintegration per minute (DPM). Unless the CPM data are corrected for quenching and converted to DPM prior to calculation of assimilation efficiency, a significant error may be introduced. (orig.) [de

Comparison of the efficacy of biodegradable and non-biodegradable scintillation liquids on the counting of tritium- and [14C]-labeled compounds

Directory of Open Access Journals (Sweden)

Medeiros R.B.

2003-01-01

Full Text Available The widespread use of ³H and 14C in research has generated a large volume of waste mixed with scintillation liquid, requiring an effective control and appropriate storage of liquid radioactive waste. In the present study, we compared the efficacy of three commercially available scintillation liquids, Optiphase HiSafe 3, Ultima-Gold(TM AB (biodegradable and Insta-Gel-XF (non-biodegradable, in terms of [14C]-glucose and [³H]-thymidine counting efficiency. We also analyzed the effect of the relative amount of water (1.6 to 50%, radioisotope concentration (0.1 to 100 nCi/ml, pH (2 to 10 and color of the solutions (samples containing 0.1 to 1.0 mg/ml of Trypan blue on the counting efficiency in the presence of these scintillation liquids. There were few significant differences in the efficiency of 14C and ³H counting obtained with biodegradable or non-biodegradable scintillation liquids. However, there was an 83 and 94% reduction in the efficiency of 14C and ³H counting, respectively, in samples colored with 1 mg/ml Trypan blue, but not with 0.1 mg/ml, independent of the scintillation liquid used. Considering the low cost of biodegradable scintillation cocktails and their efficacy, these results show that traditional hazardous scintillation fluids may be replaced with the new safe biodegradable fluids without impairment of ³H and 14C counting efficiency. The use of biodegradable scintillation cocktails minimizes both human and environmental exposure to hazardous solvents. In addition, some biodegradable scintillation liquids can be 40% less expensive than the traditional hazardous cocktails.

Scinfi, a program to calculate the standardization curve in liquid scintillation counting

International Nuclear Information System (INIS)

Grau Carles, A.; Grau Malonda, A.

1984-01-01

A code, Scinfi, was developed, written in Basic, to compute the efficiency-quench standardization curve for any radionuclide. The program requires the standardization curve for 3 H and the polynomial relations between counting efficiency and figure of merit for both 3 H and the problem (e.g. 14 C). The program is applied to the computation of the efficiency-quench standardization curve for 14 C. Five different liquid scintillation spectrometers and two scintillator solutions have been checked. The computation results are compared with the experimental values obtained with a set of 14 C standardized samples. (author)

SCINFI, a program to calculate the standardization curve in liquid scintillation counting

International Nuclear Information System (INIS)

Grau Carles, A.; Grau Malonda, A.

1984-01-01

A code, SCINFI, was developed, written in BASIC, to compute the efficiency- quench standardization curve for any radionuclide. The program requires the standardization curve for 3H and the polynomial relations between counting efficiency and figure of merit for both 3H and the problem (e.g. 14 C ). The program is applied to the computation of the efficiency-quench standardization curve for 14 c . Five different liquid scintillation spectrometers and two scintillator solutions have bean checked. The computation results are compared with the experimental values obtained with a set of 14 c standardized samples. (Author)

A new method of quench monitoring in liquid scintillation counting

International Nuclear Information System (INIS)

Horrocks, D.L.

1978-01-01

The quench level of different liquid scintillation counting samples is measured by comparing the responses (pulse heights) produced by the same energy electrons in each sample. The electrons utilized in the measurements are those of the maximum energy (Esub(max)) which are produced by the single Compton scattering process for the same energy gamma-rays in each sample. The Esub(max) response produced in any sample is related to the Esub(max) response produced in an unquenched, sealed standard. The difference in response on a logarithm response scale is defined as the ''H Number''. The H number is related to the counting efficiency of the desired radionuclide by measurement of a set of standards of known amounts of the radionuclide and different amounts of quench (standard quench curve). The concept of the H number has been shown to be theoretically valid. Based upon this proof, the features of the H number concept as embodied in the Beckman LS-8000 Series Liquid Scintillation Systems have been demonstrated. It has been shown that one H number is unique; it provides a method of instrument calibration and wide dynamic quench range measurements. Further, it has been demonstrated that the H number concept provides a universal quench parameter. Counting efficiency vs. H number plots are repeatable within the statistical limits of +-1% counting efficiency. By the use of the H number concept a very accurate method of automatic quench compensation (A.Q.C.) is possible. (T.G.)

Calibration of a liquid scintillation counter for alpha, beta and Cerenkov counting

International Nuclear Information System (INIS)

Scarpitta, S.C.; Fisenne, I.M.

1996-07-01

Calibration data are presented for 25 radionuclides that were individually measured in a Packard Tri-Carb 2250CA liquid scintillation (LS) counter by both conventional and Cerenkov detection techniques. The relationships and regression data between the quench indicating parameters and the LS counting efficiencies were determined using microliter amounts of tracer added to low 40 K borosilicate glass vials containing 15 mL of Insta-Gel XF scintillation cocktail. Using 40 K, the detection efficiencies were linear over a three order of magnitude range (10 - 10,000 mBq) in beta activity for both LS and Cerenkov counting. The Cerenkov counting efficiency (CCE) increased linearly (42% per MeV) from 0.30 to 2.0 MeV, whereas the LS efficiency was >90% for betas with energy in excess of 0.30 MeV. The CCE was 20 - 50% less than the LS counting efficiency for beta particles with maximum energies in excess of 1 MeV. Based on replicate background measurements, the lower limit of detection (LLD) for a 1-h count at the 95% confidence level, using water as a solvent, was 0.024 counts sec- -1 and 0.028 counts sec-1 for plastic and glass vials, respectively. The LLD for a 1-h-count ranged from 46 to 56 mBq (2.8 - 3.4 dpm) for both Cerenkov and conventional LS counting. This assumes: (1) a 100% counting efficiency, (2) a 50% yield of the nuclide of interest, (3) a 1-h measurement time using low background plastic vials, and (4) a 0-50 keV region of interest. The LLD is reduced an order of magnitude when the yield recovery exceeds 90% and a lower background region is used (i.e., 100 - 500 keV alpha region of interest). Examples and applications of both Cerenkov and LS counting techniques are given in the text and appendices

Detectors for proton counting. Si-APD and scintillation detectors

International Nuclear Information System (INIS)

Kishimoto, Shunji

2008-01-01

Increased intensity of synchrotron radiation requests users to prepare photon pulse detectors having higher counting rates. As detectors for photon counting, silicon-avalanche photodiode (Si-APD) and scintillation detectors were chosen for the fifth series of detectors. Principle of photon detection by pulse and need of amplification function of the detector were described. Structure and working principle, high counting rate measurement system, bunch of electrons vs. counting rate, application example of NMR time spectroscopy measurement and comments for users were described for the Si-APD detector. Structure of scintillator and photomultiplier tube, characteristics of scintillator and performance of detector were shown for the NaI detector. Future development of photon pulse detectors was discussed. (T. Tanaka)

Standardization of Ga-68 by coincidence measurements, liquid scintillation counting and 4πγ counting

International Nuclear Information System (INIS)

Roteta, Miguel; Peyres, Virginia; Rodríguez Barquero, Leonor; García-Toraño, Eduardo; Arenillas, Pablo; Balpardo, Christian; Rodrígues, Darío; Llovera, Roberto

2012-01-01

The radionuclide 68 Ga is one of the few positron emitters that can be prepared in-house without the use of a cyclotron. It disintegrates to the ground state of 68 Zn partially by positron emission (89.1%) with a maximum energy of 1899.1 keV, and partially by electron capture (10.9%). This nuclide has been standardized in the frame of a cooperation project between the Radionuclide Metrology laboratories from CIEMAT (Spain) and CNEA (Argentina). Measurements involved several techniques: 4πβ−γ coincidences, integral gamma counting and Liquid Scintillation Counting using the triple to double coincidence ratio and the CIEMAT/NIST methods. Given the short half-life of the radionuclide assayed, a direct comparison between results from both laboratories was excluded and a comparison of experimental efficiencies of similar NaI detectors was used instead. - Highlights: ► We standardized the positron emitter Ga-68 in a bilateral cooperation. ► We used several techniques, as coincidence, integral gamma and liquid scintillation. ► An efficiency comparison replaced a direct comparison of reference materials.

Standardization of 241Am by digital coincidence counting, liquid scintillation counting and defined solid angle counting

International Nuclear Information System (INIS)

Balpardo, C.; Capoulat, M.E.; Rodrigues, D.; Arenillas, P.

2010-01-01

The nuclide 241 Am decays by alpha emission to 237 Np. Most of the decays (84.6%) populate the excited level of 237 Np with energy of 59.54 keV. Digital coincidence counting was applied to standardize a solution of 241 Am by alpha-gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional counter and the results were compared with two other independent techniques: Liquid scintillation counting using the logical sum of double coincidences in a TDCR array and defined solid angle counting taking into account activity inhomogeneity in the active deposit. The results show consistency between the three methods within a limit of a 0.3%. An ampoule of this solution will be sent to the International Reference System (SIR) during 2009. Uncertainties were analysed and compared in detail for the three applied methods.

Liquid scintillation counting efficiency in three photomultiplier systems. Pure electron capture; Eficiencia de recuento por centelleo liquido en sistemas con tres fotomultiplicadores. Captura electronica pura

Energy Technology Data Exchange (ETDEWEB)

Los Arcos, J M; Grau Carles, A; Grau Malonda, A

1990-07-01

The tables of counting efficiency as a function of the figure of merit for a liquid scintillation counting system working with three phototubes are presented. The evaluation has been carried out for a Toluene-based scintillator with 5, 10 and 15 ml column, and 19 different radionuclides decaying by pure electron capture: 37Ar 41Ca, 49V, 53 Mn, 55Fe, 59Ni, 68Ge 7iGe, 82Sr, 97Tc, 118Te, 131CS, 137La, 140Ca, 157Tb, 165Er, 193Pt, 194Hg, 205Pb. (Author) 22 refs.

Comparison of triple to double coincidence ratio and Quench Parameter External methods for the determination of 3H efficiency by liquid scintillation counting

International Nuclear Information System (INIS)

Nisti, M.B.; Saueia, C.H.R.; Mazzilli, B.P.

2013-01-01

The aim of this study is to determine the tritium efficiency by liquid scintillation counting using two methodologies, Quench Parameter External (QPE) and Triple to Double Coincidence Ratio (TDCR), and to compare the results. The equipment used was the HIDEX model 300-SL Liquid Scintillation Counter, composed of three photomultipliers coupled with coincidence pulses, discrimination level and Mikro Win 2000 software. The efficiency varied from 0.028 to 0.706 cps dps -1 for QPE and from 0.061 to 0.703 cps dps -1 for TDCR. Different efficiencies were obtained using both methods, in the range from 459 to 572 quenching, above this range the efficiencies were similar. The verification of the efficiencies was performed by participating in the Intercomparison National Program (PNI). (author)

Tritium activity in milk by liquid scintillation counting

International Nuclear Information System (INIS)

Zheng Huang

1993-01-01

This paper estimates the total tritium content of both the organic and aqueous fractions simultaneously. To fulfill these conditions, the chosen scintillator should be able to accept large sample loadings and display the same counting efficiency for the organic as well as aqueous fractions of the whole milk. In an attempt to establish this method, samples from four different brands of milk were analysed using the pseudocumence based Picofluor 30 (Canberra Packard) and the di-isopropyl naphthalene based Aquasafe 500 (Zinser Analytic) scintillator solution. Glass vials were used thus enabling visual observation to be made. The tritium activities of four different brands of milks were estimated to be very low and at, or near, the detection level of the system

The liquid scintillation counting efficiency for 137mCs+137mBa and ''129 I; 'Eficiencias de recuento por centelleo liquido para el Cs+13 mBa y ''129 I

Energy Technology Data Exchange (ETDEWEB)

Grau CarLes, A.; Grau Malonda, A.

1995-07-01

We compute the liquid scintillation counting efficiency for 137Cs+137mBa and ''129 I taking into account the scintillator chemical composition. We consider the beta transition shape factors for the for bidden beta transitions of these nuclides, and the effects of 137mBa and 129mXe half-lives on the total counting efficiency. (Author) 8 refs.

Liquid scintillation counting standardization of Na129I by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1996-01-01

We describe a sample preparation procedure for liquid scintillation measurements of stable solution of Na''129I. The counting stability and spectral evolution of this solution is studied in HiSafe''tmII, Ultima-Gold''tm and Insta-Gel''r. The liquid scintillation measurements have been carried efficiencies lower than 0.4%. the solution has been standardized in terms of activity concentration to an overall uncertainty of 0.46% (k=1 )

Standardization of {sup 241}Am by digital coincidence counting, liquid scintillation counting and defined solid angle counting

Energy Technology Data Exchange (ETDEWEB)

Balpardo, C., E-mail: balpardo@cae.cnea.gov.a [Laboratorio de Metrologia de Radioisotopos, CNEA, Buenos Aires (Argentina); Capoulat, M.E.; Rodrigues, D.; Arenillas, P. [Laboratorio de Metrologia de Radioisotopos, CNEA, Buenos Aires (Argentina)

2010-07-15

The nuclide {sup 241}Am decays by alpha emission to {sup 237}Np. Most of the decays (84.6%) populate the excited level of {sup 237}Np with energy of 59.54 keV. Digital coincidence counting was applied to standardize a solution of {sup 241}Am by alpha-gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional counter and the results were compared with two other independent techniques: Liquid scintillation counting using the logical sum of double coincidences in a TDCR array and defined solid angle counting taking into account activity inhomogeneity in the active deposit. The results show consistency between the three methods within a limit of a 0.3%. An ampoule of this solution will be sent to the International Reference System (SIR) during 2009. Uncertainties were analysed and compared in detail for the three applied methods.

Liquid Scintillation counting Standardization of 22 NaCl by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1995-09-01

We describe a procedure for preparing a stable solution of ''22 NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4/% and an overall uncertainty of 0.35%

System and method of liquid scintillation counting

International Nuclear Information System (INIS)

Rapkin, E.

1977-01-01

A method of liquid scintillation counting utilizing a combustion step to overcome quenching effects comprises novel features of automatic sequential introduction of samples into a combustion zone and automatic sequential collection and delivery of combustion products into a counting zone. 37 claims, 13 figures

Determination of Np, Pu and Am in high level radioactive waste with extraction-liquid scintillation counting

International Nuclear Information System (INIS)

Yang Dazhu; Zhu Yongjun; Jiao Rongzhou

1994-01-01

A new method for the determination of transuranium elements, Np, Pu and Am with extraction-liquid scintillation counting has been studied systematically. Procedures for the separation of Pu and Am by HDEHP-TRPO extraction and for the separation of Np by TTA-TiOA extraction have been developed, by which the recovery of Np, Pu and Am is 97%, 99% and 99%, respectively, and the decontamination factors for the major fission products ( 90 Sr, 137 Cs etc.) are 10 4 -10 6 . Pulse shape discrimination (PSD) technique has been introduced to liquid scintillation counting, by which the counting efficiency of α-activity is >99% and the rejection of β-counts is >99.95%. This new method, combining extraction and pulse shape discrimination with liquid scintillation technique, has been successfully applied to the assay of Np, Pu and Am in high level radioactive waste. (author) 7 refs.; 7 figs.; 4 tabs

The ionization quench factor in liquid-scintillation counting standardizations

CERN Document Server

Grau-Malonda, A

1999-01-01

We present a new detailed analysis of the ionization quench function Q(E) used in calculating the counting efficiency in liquid-scintillation counting (LSC), which shows that Q(0)=1, and permits one to derive Q(E) as a function of the electron energy and the parameter kB. The coefficients are tabulated by applying a new empirical formula of Q(E) for kB values in the range between 0.001 and 0.20 gMeV sup - sup 1 cm sup - sup 2. We demonstrate the convenience of applying sup 3 H and sup 5 sup 4 Mn for beta-ray and electron capture standardizations, respectively.

Scintillation counting: an extrapolation into the future

International Nuclear Information System (INIS)

Ross, H.H.

1983-01-01

Progress in scintillation counting is intimately related to advances in a variety of other disciplines such as photochemistry, photophysics, and instrumentation. And while there is steady progress in the understanding of luminescent phenomena, there is a virtual explosion in the application of semiconductor technology to detectors, counting systems, and data processing. The exponential growth of this technology has had, and will continue to have, a profound effect on the art of scintillation spectroscopy. This paper will review key events in technology that have had an impact on the development of scintillation science (solid and liquid) and will attempt to extrapolate future directions based on existing and projected capability in associated fields. Along the way there have been occasional pitfalls and several false starts; these too will be discussed as a reminder that if you want the future to be different than the past, study the past

Counting efficiency formulae for two, three or four photomultiplier systems

International Nuclear Information System (INIS)

Grau Malonda, A.

1993-01-01

Counting efficiency formulae as a function of the non-detection probability and the electron distributions for systems with two, three or dour photomultipliers are obtained in this paper. It is assumed that the photocathode electron emission follows the Poisson distribution. The obtained formulae are basic to compute the counting efficiency in liquid scintillation spectrometers

Liquid Scintillation Counting Standardization of 22NaCl by te CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1995-01-01

We describe a procedure for preparing a stable solution of ''22NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4 % and an overall uncertainty of 0.35 %. (Author) 4 refs

2003: A centennial of spinthariscope and scintillation counting

International Nuclear Information System (INIS)

Kolar, Z.I.; Hollander, W. den

2004-01-01

In 1903 W. Crookes demonstrated in England his 'spinthariscope' for the visual observation of individual scintillations caused by alpha particles impinging upon a ZnS screen. In contrast to the analogue methods of radiation measurements in that time the spinthariscope was a single-particle counter, being the precursor of scintillation counters since. In the same period F. Giesel, J. Elster and H. Geitel in Germany also found that scintillations from ZnS represent single particle events. This paper summarises the historical events relevant to the advent of scintillation counting

Characteristics of commercially available well scintillation counting systems

International Nuclear Information System (INIS)

Morris, A.C. Jr.; Dudley, R.A.

1977-01-01

The document contains data on commercially available well scintillation counting systems as collected during early 1977, and up-dated in July 1977, by the staff of the Medical Application Section, Division of Life Sciences, IAEA. These data also appear as Appendix 2 of IAEA-201, Well Scintillation Counting Systems for Nuclear Medicine Applications in Developing Countries, Vienna, 1977. An attempt was made to include instruments currently offered by all manufacturers. However, it is inevitable that several manufacturers remain unknown to the Section, and a number of known manufacturers failed to provide adequate information. (orig.) [de

Rapid radiometric detection of microbial contamination using 14C-glucose and standard liquid scintillation counting system

International Nuclear Information System (INIS)

Joshi, S.H.; Kamble, S.B.; Pilkhwal, N.S.; Ramamoorthy, N.

1998-01-01

A simple and rapid method for detection of microbial contamination based on quantitation of 14 CO 2 released during metabolism of 14 C-Glucose by microorganisms is reported. Liquid scintillation counting system (LSCS) with a modified sample preparation method was utilised. The scintillator was impregnated on Whatman-1 paper on which 14 CO 2 evolved during metabolism could be absorbed. The important parameters of counting such as efficiency, position sensitivity and geometry as well as effect of NaOH quantity and of microbial load on detection period were studied. The efficiency of radioactivity assay was 18±2.8 %. Contamination of the order of 5-10 organism/ml of product could be detected in about 24 hours. (author)

Solid scintillator 'Ready Cap' for measurement with a liquid scintillation counter

International Nuclear Information System (INIS)

Ijiri, Kenichi; Endo, Masashi; Nogawa, Norio; Tsuda, Shoko; Nakamura, Aiko; Morikawa, Naotake; Osaki, Susumu.

1990-01-01

'Ready Cap', a small plastic container coated with solid scintillator has recently been introduced (Beckman Instruments, Inc.). Pulse height spectra and counting efficiencies obtained with a liquid scintillator and Ready Cap using a liquid scintillation counter were compared for 15 different radionuclides. For radionuclides emitting low-energy β-rays or characteristic X-rays, the spectra for Ready Cap shifted toward the higher energy side compared with the spectra for the liquid scintillator. This tendency was reversed for the nuclides emitting higher-energy β-radiations ( 36 Cl and 32 P). Generally, counting efficiencies both in Ready Cap and in liquid scintillator increased with increase in the energy of β- or X-rays. For some nuclides, Ready Cap gave higher counting efficiencies and for others it gave lower values than in the liquid scintillator. However, the differences were not large within each nuclide. The use of Ready Cap is recommended for measurements of radionuclides when liquid scintillation cocktails have no means of waste disposal under the present Japanese radioisotope regulation. (author)

Liquid organic scintillator in a polymerizable emulsion, its application to radioactive counting and process for its destruction

International Nuclear Information System (INIS)

O'Brien, R.E.; Krieger, J.K.

1981-01-01

Scintillation organic liquid mixture for performing very efficient counts on compound solutions labelled with a radioactive indicator containing up to 10% water by volume and which is easily polymerizable into a solid substance, in order to facilitate its elimination. The mixture includes a polymerizable organic solvent, a solubilizing agent, an intermediate solvent and an organic scintillator [fr

14C measurement: effect of variations in sample preparation and storage on the counting efficiency for 14C using a carbo-sorb/permafluor E+ liquid scintillation cocktail

International Nuclear Information System (INIS)

Kramer, S.J.; Milton, G.M.; Repta, C.J.W.

1995-06-01

The effect of variations in sample preparation and storage on the counting efficiency for 14 C using a Carbo-Sorb/PermafluorE+ liquid scintillation cocktail has been studied, and optimum conditions are recommended. (author). 2 refs., 2 tabs., 4 figs

Liquid scintillation counting (LSC) - an overview

International Nuclear Information System (INIS)

Ravi, S.; Mathew, K.M.

2005-01-01

In Liquid Scintillation Counting, the amount of light produced is proportional to the amount of radiation present in the sample and the energy of the light produced is proportional to the energy of the radiation that is present in the sample. This makes LSC a very convenient tool to measure radioactivity

Direct photon-counting scintillation detector readout using an SSPM

International Nuclear Information System (INIS)

Stapels, Christopher J.; Squillante, Michael R.; Lawrence, William G.; Augustine, Frank L.; Christian, James F.

2007-01-01

Gamma-ray detector technologies, capable of providing adequate energy information, use photomultiplier tubes (PMTs) or silicon avalanche photodiodes to detect the light pulse from a scintillation crystal. A new approach to detect the light from scintillation materials is to use an array of small photon counting detectors, or a 'detector-on-a-chip' based on a novel 'Solid-state Photomultiplier' (SSPM) concept. A CMOS SSPM coupled to a scintillation crystal uses an array of CMOS Geiger photodiode (GPD) pixels to collect light and produce a signal proportional to the energy of the radiation. Each pixel acts as a binary photon detector, but the summed output is an analog representation of the total photon intensity. We have successfully fabricated arrays of GPD pixels in a CMOS environment, which makes possible the production of miniaturized arrays integrated with the detector electronics in a small silicon chip. This detector technology allows for a substantial cost reduction while preserving the energy resolution needed for radiological measurements. In this work, we compare designs for the SSPM detector. One pixel design achieves maximum detection efficiency (DE) for 632-nm photons approaching 30% with a room temperature dark count rate (DCR) of less than 1 kHz for a 30-μm-diameter pixel. We characterize after pulsing and optical cross talk and discuss their effects on the performance of the SSPM. For 30-μm diameter, passively quenched CMOS GPD pixels, modeling suggests that a pixel spacing of approximately 90 μm optimizes the SSPM performance with respect to DE and cross talk

Liquid scintillation alpha counting and spectrometry and its application to bone and tissue samples

International Nuclear Information System (INIS)

McDowell, W.J.; Weiss, J.F.

1976-01-01

Three methods for determination of alpha-emitting nuclides using liquid scintillation counting are compared, and the pertinent literature is reviewed. Data showing the application of each method to the measurement of plutonium concentration in tissue and bone samples are presented. Counting with a commercial beta-liquid scintillation counter and an aqueous-phase-accepting scintillator is shown to be accurate only in cases where the alpha activity is high (several hundred counts/min or more), only gross alpha counting is desired, and beta-gamma emitters are known to be absent from the sample or present at low levels compared with the alpha activity. Counting with the same equipment and an aqueous immiscible scintillator containing an extractant for the nuclide of interest (extractive scintillator) is shown to allow better control of alpha peak shift due to quenching, a significant reduction of beta-gamma interference, and, usually, a low background. The desirability of using a multichannel pulse-height analyzer in the above two counting methods is stressed. The use of equipment and procedures designed for alpha liquid scintillation counting is shown to allow alpha spectrometry with an energy resolution capability of 200 to 300 keV full-peak-width-at-half-peak-height and a background of 0.3 to 1.0 counts/min, or as low as 0.01 counts/min if pulse-shape discrimination methods are used. Methods for preparing animal bone and tissue samples for assay are described

Data process of liquid scintillation counting

International Nuclear Information System (INIS)

Ishikawa, Hiroaki; Kuwajima, Susumu.

1975-01-01

The use of liquid scintillation counting system has been significantly spread because automatic sample changers and printers have recently come to be incorporated. However, the system will be systematized completely if automatic data processing and the sample preparation of radioactive materials to be measured are realized. Dry or wet oxidation method is applied to the sample preparation when radioactive materials are hard to dissolve into scintillator solution. Since these several years, the automatic sample combustion system, in which the dry oxidation is automated, has been rapidly spread and serves greatly to labor saving. Since the printers generally indicate only counted number, data processing system has been developed, and speeded up calculating process, which automatically corrects quenching of samples for obtaining the final radioactivity required. The data processing system is roughly divided into on-line and off-line systems according to whether computers are connected directly or indirectly, while its hardware is classified to input, calculating and output devices. Also, the calculation to determine sample activity by external standard method is explained. (Wakatsuki, Y.)

Application of PSD for low level alpha counting using liquid scintillation counting

International Nuclear Information System (INIS)

Krishnamachari, G.; Vaze, P.K.; Iyer, M.R.

1989-01-01

In the liquid scintillator the light produced by alpha particles decays differently than those produced by electrons. Pulse shape discrimination (PSD) methods are employed to estimate low levels of alpha emitting radionuclides by reducing the background due to either beta or gamma events. An attempt is being made to develop a liquid scintillation counting sytem using a simple PSD circuit to achieve a background of 0.01 counts/min. The PSD circuit is based on measuring zero cross over points to differentiate particle types. The input signal is first differentiated by a delay line and subsequently by a RC circuit. The width of the initial part of the doubly differentiated pulse is different for alpha and beta pulses. This width is converted to amplitude by a time-to-amplitude converter (TAC). The higher amplitude pulses from the TAC are due to alpha particles and they are separated by an integral discriminator. The output from the integral discriminator opens a linear gate to record the pulse height spectrum. The figure of merit of the PSD circuit and background in the alpha energy channel have been worked out using different scintillator types. (author). 4 figs

Liquid scintillation counting techniques for the determination of some alpha emitting actinides: a review

International Nuclear Information System (INIS)

Mirashi, N.N.; Chander, Keshav; Aggarwal, S.K.

2000-12-01

The present report is a review of the work on liquid scintillation counting techniques, for the determination of alpha emitting actinides like uranium, plutonium, americium etc; for the last three decades (1970-1999). It covers the progress that has taken place in conventional liquid scintillation counting employing various solvents, scintillators and extractants. There is gradual development in instrumentation from integral counting of alpha emitters to alpha liquid scintillation spectrometry to resolve and identify different alpha emitters. These advancements have led to Pulse Shape Analysis (PSA) and Photon Electron Rejecting Alpha Liquid Scintillation Spectrometry (PERALS) techniques for the determination of the alpha emitters in the presence of beta and gamma activity. These techniques allow the determination of actinides at very low levels which has increased their applications to almost all the fields of chemistry; be it biomedical, environmental, geological or process chemistry of nuclear fuels. The development of biphasic technique using various extractants to separate different elements and counting in presence of one another has been made possible. Inorganic scintillators have been recently developed which have the advantage of eliminating effects of quenching and presence of beta/gamma emitting actinides. This review will serve as a reference to those who want to carry out work in the field of determination of actinides using liquid scintillation counting techniques. (author)

Optics study of liquid scintillation counting systems

International Nuclear Information System (INIS)

Duran Ramiro, M. T.; Garcia-Torano, E.

2005-01-01

Optics is a key issue in the development of any liquid scintillation counting (LSC) system. Light emission in the scintillating solution, transmission through the vial and reflector design are some aspects that need to be considered in detail. This paper describes measurements and calculations carried out to optimise these factors for the design of a new family of LSC counters. Measurements of the light distribution emitted by a scintillation vial were done by autoradiographs of cylindrical vials made of various materials and results were compared to those obtained by direct measurements of the light distribution made by scanning the vial with a photomultiplier tube. Calculations were also carried out to study the light transmission in the vial and the optimal design of the reflector for a system with one photomultiplier tube. (Author)

Applications of low level liquid scintillation counting

International Nuclear Information System (INIS)

Noakes, J.E.

1983-01-01

Low level liquid scintillation counting is reviewed in terms of its present use and capabilities for measuring low activity samples. New areas of application of the method are discussed with special interest directed to the food industry and environmental monitoring. Advantages offered in the use of a low background liquid scintillation counter for the nuclear power industry and nuclear navy are discussed. Attention is drawn to the need for commercial development of such instrumentation to enable wider use of the method. A user clientele is suggested as is the required technology to create such a counter

Optimisation of liquid scintillation counting conditions to determine low activity levels of tritium and radiostrontium in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Rauret, Gemma; Mestres, J.S.; Ribera, Merce; Rajadel, Pilar (Barcelona Univ. (Spain). Dept. de Quimica Analitica)

1990-08-01

An optimisation of the counting conditions for the measurement of aqueous solutions of tritium or radiostrontium using Insta-Gel II as scintillator is presented. The variables optimised were the window, the ratio of mass of sample to mass of scintillator and the total volume of the counting mixture. An optimisation function which takes into account each of these variables, the background and also the efficiency is proposed. The conditions established allow the lowest possible detection limit to be reached. For tritium, this value was compared with that obtained when the standard method for water analysis was applied. (author).

Liquid scintillation counting standardization of ''125 I in organic and inorganic samples by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J.M.; Grau Carles, A.

1994-01-01

The liquid scintillation counting standardization of organic and inorganic samples of ''125 I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%

Calculation of the detection efficiency in liquid scintillators. II. Single positron emitters

International Nuclear Information System (INIS)

Grau Malonda, A.; Garcia Torano, E.

1982-01-01

Counting efficiency as a function of the figure of merit for 30 positron emitters has been computed from the positron energy spectrum. Only the efficiency contribution of positrons has been taken into consideration. The contribution of the annihilation photons depending on the volume of the scintillator will be investigated in a near future. Efficiency vs figure of merit is plotted and tabulated. (Author) 19 refs

Liquid scintillation counting standardization of 125I in organic and inorganic samples by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J. M.; Grau Carles, A.

1994-01-01

The liquid scintillation counting standardization of organic and inorganic samples of ''I25I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%. (Author) 14 refs

Pulse-duration discrimination for increasing counting characteristic plateau and for improving counting rate stability of a scintillation counter

International Nuclear Information System (INIS)

Kuz'min, M.G.

1977-01-01

For greater stability of scintillation counters operation, discussed is the possibility for increasing the plateau and reducing its slope. Presented is the circuit for discrimination of the signal pulses from input pulses of a photomultiplier. The counting characteristics have been measured with the scintillation detectors being irradiated by different gamma sources ( 60 Co, 137 Cs, 241 Am) and without the source when the scintillation detector is shielded by a tungsten cylinder with a wall thickness of 23 mm. The comparison has revealed that discrimination in duration increase the plateau and reduces its slope. Proceeding from comparison of the noise characteristics, the relationship is found between the noise pulse number and gamma radiation energy. For better stability of the counting rate it is suggested to introduce into the scintillation counter the circuit for duration discrimination of the output pulses of a photomultiplier

Liquid scintillation: Sample preparation and counting atypical emissions

International Nuclear Information System (INIS)

Anon.

1991-01-01

Liquid scintillation sample preparation has the most published information but the least amount of definitive technical direction because the chemical and physical nature of the samples from biological investigations varies widely. This chapter discusses the following related topics: Aqueous Samples; Tissue Solubilizers; Absorption of 14 CO 2 ; Sample Combustion Methods; Heterogeneous Systems; Sample Preparation Problems (colored samples, chemiluminescence, photoluminescence, static electricity); Counting Various Types of Emitters; Counting Atypical Emissions. 2 refs., 2 figs

Study on determination of 90Sr by liquid scintillation spectrometry

International Nuclear Information System (INIS)

Zhai Xiufang; Li Weiping; Tian Mei; Zou Ronghu

2012-01-01

Both of Liquid scintillation counting and Cerenkov counting can be used to determinate 90 Sr in samples by Liquid scintillation spectrometry. In this work, effects of scintillation vials wit-h different material, Liquid scintillation cocktails, sample volume, Strontium carrier, pH, quenching (chemical quenching and color quenching)are studied, and both counting methods are compared. For Liquid scintillation counting. The results show that the best appropriate volume ratio of sample and liquid scintillation cocktail is 8:12 for OPTIPHASE HISAFE-3 and OPTIPHASE HISAFE-2, stability of solution decreased when sample load exceeds the maximum load for both Liquid scintillation cocktails, and OPTIPHASE HISAFE-3 also show superior performance for high saline solution. The type of scintillation vial haven't clear influence on the MDA of 90 Sr. Chemical quenching and color quenching can decrease the counting efficiency. For Cerenkov counting, the lowest MDA is obtained when polyethylene plastic vial is used and sample volume is 20 ml. Color quenching decreases the counting efficiency, while there isn't chemical quenching for Cerenkov counting. The MDA of 90 Sr is 1.19 and 1.00 Bq/L for Liquid scintillation counting and Cerenkov counting with the optimal labeling condition. (authors)

Standardization of Ga-68 by coincidence measurements, liquid scintillation counting and 4πγ counting.

Science.gov (United States)

Roteta, Miguel; Peyres, Virginia; Rodríguez Barquero, Leonor; García-Toraño, Eduardo; Arenillas, Pablo; Balpardo, Christian; Rodrígues, Darío; Llovera, Roberto

2012-09-01

The radionuclide (68)Ga is one of the few positron emitters that can be prepared in-house without the use of a cyclotron. It disintegrates to the ground state of (68)Zn partially by positron emission (89.1%) with a maximum energy of 1899.1 keV, and partially by electron capture (10.9%). This nuclide has been standardized in the frame of a cooperation project between the Radionuclide Metrology laboratories from CIEMAT (Spain) and CNEA (Argentina). Measurements involved several techniques: 4πβ-γ coincidences, integral gamma counting and Liquid Scintillation Counting using the triple to double coincidence ratio and the CIEMAT/NIST methods. Given the short half-life of the radionuclide assayed, a direct comparison between results from both laboratories was excluded and a comparison of experimental efficiencies of similar NaI detectors was used instead. Copyright © 2012 Elsevier Ltd. All rights reserved.

Alpha liquid scintillation counting: past, present, and future

International Nuclear Information System (INIS)

McDowell, W.J.

1979-01-01

Beta liquid scintillation counting has been used for about 30 years, and its effectiveness for alpha particles has been known for almost that long; however, the technique has not been widely applied to alpha particle detection because of poor energy resolution, high background, and variable interference from beta and gamma radiation. Beginning with the work of Horrocks in the early 1960s, improvements in energy resolution and background rejection have been made. Further developments at Oak Ridge National Laboratory over the past 10 to 12 years have resulted in improved methods of sample preparation (using liquid-liquid extraction methods to isolate the sample and introduce it into the scintillator) and better instrumentation, including electronic rejection of beta and gamma pulses. Energy resolutions of 200- to 300-keV FWHM and background counts of 0.01 cpm are now routine. Alpha liquid scintillation spectrometry is now suitable for a wide range of applications, from the accurate quantitative determination of relatively large amounts of known nuclides in laboratory-generated samples to the detection and identification of very small, subpicocurie amounts of alpha emitters in environmental-type samples. Suitable nuclide separation procedures, sample preparation methods, and instrument configurations are outlined for a variety of analyses

Measurement of radionuclides using ion chromatography and flow-cell scintillation counting with pulse shape discrimination

International Nuclear Information System (INIS)

DeVol, T.A.; Fjeld, R.A.

1995-01-01

A project has been initiated at Clemson Univ. to develop a HPLC/flow- cell system for analysis of non-gamma emitting radionuclides in environmental samples; an important component is development of a low background flow-cell detector that counts alpha and beta particles separately through pulse shape discrimination. Objective of the work presented here is to provide preliminary results of an evaluation of the following scintillators: CaF 2 :Eu, scintillating glass, and BaF 2 . Slightly acidic aqueous solutions of the alpha emitter 233 U and the beta emitter 45 Ca were used. Detection efficiencies and minimum detectable activities were determined

Compositions and process for liquid scintillation counting

International Nuclear Information System (INIS)

1974-01-01

Liquid scintillation counting compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers which give homogeneous monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous monophasic-appearing aqueous counting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

Well scintillation counting systems for nuclear medicine applications in developing countries

International Nuclear Information System (INIS)

1977-01-01

This report of a consultants' meeting, organized by the Medical Applications Section of the Division of Life Sciences, IAEA, during the period 23-25 May 1977, examines well scintillation counting systems in the light of the requirements of laboratories in developing countries. It has three facets: 1) identification of the most rewarding applications of nuclear medicine techniques, 2) identification of favourable design attributes of instruments used in such applications, and 3) development of maintenance strategies to assure reliable performance of the instruments once put into service. Some characteristics of commercially available well scintillation counting systems are given

High-efficiency organic glass scintillators

Science.gov (United States)

Feng, Patrick L.; Carlson, Joseph S.

2017-12-19

A new family of neutron/gamma discriminating scintillators is disclosed that comprises stable organic glasses that may be melt-cast into transparent monoliths. These materials have been shown to provide light yields greater than solution-grown trans-stilbene crystals and efficient PSD capabilities when combined with 0.01 to 0.05% by weight of the total composition of a wavelength-shifting fluorophore. Photoluminescence measurements reveal fluorescence quantum yields that are 2 to 5 times greater than conventional plastic or liquid scintillator matrices, which accounts for the superior light yield of these glasses. The unique combination of high scintillation light-yields, efficient neutron/gamma PSD, and straightforward scale-up via melt-casting distinguishes the developed organic glasses from existing scintillators.

QUENCH: A software package for the determination of quenching curves in Liquid Scintillation counting.

Science.gov (United States)

Cassette, Philippe

2016-03-01

In Liquid Scintillation Counting (LSC), the scintillating source is part of the measurement system and its detection efficiency varies with the scintillator used, the vial and the volume and the chemistry of the sample. The detection efficiency is generally determined using a quenching curve, describing, for a specific radionuclide, the relationship between a quenching index given by the counter and the detection efficiency. A quenched set of LS standard sources are prepared by adding a quenching agent and the quenching index and detection efficiency are determined for each source. Then a simple formula is fitted to the experimental points to define the quenching curve function. The paper describes a software package specifically devoted to the determination of quenching curves with uncertainties. The experimental measurements are described by their quenching index and detection efficiency with uncertainties on both quantities. Random Gaussian fluctuations of these experimental measurements are sampled and a polynomial or logarithmic function is fitted on each fluctuation by χ(2) minimization. This Monte Carlo procedure is repeated many times and eventually the arithmetic mean and the experimental standard deviation of each parameter are calculated, together with the covariances between these parameters. Using these parameters, the detection efficiency, corresponding to an arbitrary quenching index within the measured range, can be calculated. The associated uncertainty is calculated with the law of propagation of variances, including the covariance terms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Measurement of scintillation decay curves by a single photon counting technique

International Nuclear Information System (INIS)

Noguchi, Tsutomu

1978-01-01

An improved apparatus suitable for the measurement of spectroscopic scintillation decay curves has been developed by combination of a single photon counting technique and a delayed coincidence method. The time resolution of the apparatus is improved up to 1.16 nsec (FWHM), which is obtained from the resolution function of the system for very weak Cherenkov light flashes. Systematic measurement of scintillation decay curves is made for liquid and crystal scintillators including PPO-toluene, PBD-xylene, PPO-POPOP-toluene, anthracene and stilbene. (auth.)

Application of avalanche photodiodes for the measurement of actinides by alpha liquid scintillation counting

International Nuclear Information System (INIS)

Reboli, A.

2005-10-01

Alpha emitters analysis using liquid scintillation spectroscopy is often used when sensitivity and fast samples preparation are the important points. A more extensive use of this technique is until now limited by its poor resolution compared to alpha particle spectroscopy with semiconductor detectors. To improve the resolution and thus promote this method for the measurement of actinides in environment, we have tested silicon avalanche photodiodes (APD) as new detectors for scintillation photons. The set-up consists of a large area avalanche photodiode (16 mm diameter) coupled to a thin vial containing alpha-emitters within a liquid scintillation cocktail. After optimization of several parameters like bias voltage, temperature, counting geometry and composition of the scintillating cocktail, energy resolutions have been found to be better than those obtained with standard photomultiplier tubes (PMT): 5% (200 keV FWHM) for 232 Th and 4.2% (240 keV FWHM) for 236 Pu. Our results show that the improvement is due to less fluctuations associated with light collection since the spatial response of APDs is more uniform than that of PMTs. The expected gain on quantum efficiency (80% for APDs instead of 25% for PMTs) is nullified by a corresponding increase on electronic noise and excess noise factor. Significant better results are foreseen by using green scintillators (450 - 550 nm wavelengths region) with larger Stokes-shift and blue-enhanced APDs which reach their maximum quantum efficiency in this region. (author)

Applications of liquid scintillation tubes

International Nuclear Information System (INIS)

Broga, D.W.

1977-01-01

A new cocktail containing device for liquid scintillation counting, the scintillation tube, consists of a two-layered plastic bag which is heatsealed after the cocktail and sample have been placed in it. It is then placed in a carrying vial and counted in a conventional liquid scintillation counter. These tubes have proved to be a practical and economical alternative to vials. Some of their advantages are elimination of absorption problems, transparency, lower background and higher counting efficiency, low breakage danger and savings in waste disposal costs. Two applications for which the tubes are particularly suitable are the counting of laboratory swipes and urine analysis. (author)

A scintillation detector signal processing technique with active pileup prevention for extending scintillation count rates

International Nuclear Information System (INIS)

Wong, W.H.; Li, H.

1998-01-01

A new method for processing signals from scintillation detectors is proposed for very high count-rate situations where multiple-event pileups are the norm. This method is designed to sort out and recover every impinging event from multiple-event pileups while maximizing the collection of scintillation signal for every event to achieve optimal accuracy in determining the energy of the event. For every detected event, this method cancels the remnant signals from previous events, and excludes the pileup of signals from following events. With this technique, pileup events can be recovered and the energy of every recovered event can be optimally measured despite multiple pileups. A prototype circuit demonstrated that the maximum count rates have been increased by more than 10 times, comparing to the standard pulse-shaping method, while the energy resolution is as good as that of the pulse shaping (or the fixed integration) method at normal count rates. At 2 x 10 6 events/sec for NaI(Tl), the true counts acquired are 3 times more than the delay-line clipping method (commonly used in fast processing designs) due to events recovered from pileups. Pulse-height spectra up to 3.5 x 10 6 events/sec have been studied

Some studies on extractive liquid scintillation counting for Th-234/P-234m

International Nuclear Information System (INIS)

Grudpan, K.; Singjanusong, P.; Punyodom, W.

1990-01-01

A study on solvent extraction for Th-234/Pa-234m by liquid scintillation counting has not been reported. This paper will report an application of the technique on such a study. In a hydrochloric acid solution of an uranyl salt, Pa-234m which is one of the daughters of U-238 can be separated by extraction into isobutyl methyl ketone (IBMK). Cerenkov counting was applied for the extraction investigation. Solvent extraction of Th-234/Pa-234m from an aqueous nitric acid solution by TOPO/PPO in toluene by using liquid scintillation counting will be described

Correct liquid scintillation counting of steroids and glycosides in RIA samples: a comparison of xylene-based, dioxane-based and colloidal counting systems. Chapter 14

International Nuclear Information System (INIS)

Spolders, H.

1977-01-01

In RIA, the following parameters are important for accurate liquid scintillation counting. (1) Absence of chemiluminescence. (2) Stability of count rate. (3) Dissolving properties for the sample. For samples with varying colours, a quench correction must be applied. For any type of accurate quench correction, a homogeneous sample is necessary. This can be obtained if proteins and the buffer can be dissolved completely in the scintillator solution. In this paper, these criteria are compared in xylene-based, dioxane-based and colloidal scintillation solutions for either bound or free antigens of different polarity. The labelling radioisotope used was 3 H. Using colloidal scintillators with plasma and buffer samples, phasing or sedimentation of salt or proteins sometimes occurs. The influence of sedimentation or phasing on count rate stability and correct quench correction is illustrated by varying the ratio between the scintillator solution and a RIA sample containing a semi-polar steroid aldosterone. (author)

Liquid scintillation counting of calcium-45 in plant and soil material

International Nuclear Information System (INIS)

Waller, S.S.; Dodd, J.D.

1977-01-01

The recovery efficiencies of 45 Ca, for plant material using dry ashing with HCL as the extractant, and for soils using column extraction with MgCl 2 as the extractant, have been determined. The extraction and detection procedures, using available scintillation solvent systems, are given and show a combination of a high counting efficiency with high recovery efficiencies. The extraction procedures are simple, involving minimal operator time, and allow simultaneous 45 Ca determination in both plant and soil material. Both extraction procedures exhibit good reproducibility over a wide range of specific activities while being relatively insensitive to quenching and carrier calcium normally encountered in plant and soil material. These procedures are particularly useful in ecological studies requiring the examination of a large number of plant and/or soil samples over a wide range of radioactive concentrations. (U.K.)

Determination of 90SR in food using extraction chromatography and LSC - Liquid Scintillation Counting

International Nuclear Information System (INIS)

Temba, Eliane S.C.; Amaral, Angela M.; Reis Junior, Aluisio S.; Monteiro, Roberto P.G.

2013-01-01

A methodology for the determination of 90 Sr in food is described. The procedure involved a preliminary freeze-drying of the samples followed by dry-ashing and sample digestion. The separation procedure was carried out using extraction chromatography with Sr Resin, from Eichrom, and 90 Sr was measured by liquid scintillation counting (LSC). A certified reference material, IAEA-375, was analyzed in order to evaluate the reliability of the method, and the results showed good agreement between the measured and certified values. The chemical yield was above 90% and the typical counting efficiency was 82%. The calculated limit of detection was 4.8 x 10 -3 Bq g -1 . (author)

Combustion water purification techniques influence on OBT analysing using liquid scintillation counting method

International Nuclear Information System (INIS)

Varlam, C.; Vagner, I.; Faurescu, I.; Faurescu, D.

2015-01-01

In order to determine organically bound tritium (OBT) from environmental samples, these must be converted into water, measurable by liquid scintillation counting (LSC). For this purpose we conducted some experiments to determine OBT level of a grass sample collected from an uncontaminated area. The studied grass sample was combusted in a Parr bomb. However usual interfering phenomena were identified: color or chemical quench, chemiluminescence, overlap over tritium spectrum because of other radionuclides presence as impurities ( 14 C from organically compounds, 36 Cl as chloride and free chlorine, 40 K as potassium cations) and emulsion separation. So the purification of the combustion water before scintillation counting appeared to be essential. 5 purification methods were tested: distillation with chemical treatment (Na 2 O 2 and KMnO 4 ), lyophilization, chemical treatment (Na 2 O 2 and KMnO 4 ) followed by lyophilization, azeotropic distillation with toluene and treatment with a volcanic tuff followed by lyophilization. After the purification step each sample was measured and the OBT measured concentration, together with physico-chemical analysis of the water analyzed, revealed that the most efficient method applied for purification of the combustion water was the method using chemical treatment followed by lyophilization

Liquid scintillation counting of 3H-thymidine incorporated into rat lens DNA

International Nuclear Information System (INIS)

Soederberg, P.G.; Lindstroem, B.

1990-01-01

DNA synthesis in the lens has previously been localized by autoradiography following incorporation of 3 H-thymidine. For the quantification of DNA synthesis in the lens, pooling of lenses and extraction of the DNA for liquid scintillation counting, has formerly been adapted. In the present investigation a method has been developed for the extraction of the unincorporated tracer from whole lenses after short time incubation in a medium containing 3 H-thymidine. The 3 H-thymidine incorporated into individual lenses was then detected by liquid scintillation counting after dissolution of the lenses. The sources of the variation in the method are evaluated. (author)

Evaluation of the uncertainty for the efficiency curve determination of 210Pb by liquid scintillation

International Nuclear Information System (INIS)

Sampaio, C.S.; Sousa, W.O.; Dantas, B.M.

2014-01-01

Methodologies for the evaluation of uncertainties associated with the determination of the efficiency curve of 210 Pb by liquid scintillation counting (LSC) are presented. No statistical difference were found when compared the uncertainties of the curves that represented the counting net before and after the secular equilibrium between 210 Pb and 210 Bi, nether when compared the curves when counting only 210 Pb and the curve with the total count of 210 Pb and 210 Bi, for the same time interval after precipitation. (author)

Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

Energy Technology Data Exchange (ETDEWEB)

Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

2016-08-21

Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

International Nuclear Information System (INIS)

Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

2016-01-01

Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

Monte Carlo simulations and measurements for efficiency determination of lead shielded plastic scintillator detectors

Science.gov (United States)

Yasin, Zafar; Negoita, Florin; Tabbassum, Sana; Borcea, Ruxandra; Kisyov, Stanimir

2017-12-01

The plastic scintillators are used in different areas of science and technology. One of the use of these scintillator detectors is as beam loss monitors (BLM) for new generation of high intensity heavy ion in superconducting linear accelerators. Operated in pulse counting mode with rather high thresholds and shielded by few centimeters of lead in order to cope with radiofrequency noise and X-ray background emitted by accelerator cavities, they preserve high efficiency for high energy gamma ray and neutrons produced in the nuclear reactions of lost beam particles with accelerator components. Efficiency calculation and calibration of detectors is very important before their practical usage. In the present work, the efficiency of plastic scintillator detectors is simulated using FLUKA for different gamma and neutron sources like, 60Co, 137Cs and 238Pu-Be. The sources are placed at different positions around the detector. Calculated values are compared with the measured values and a reasonable agreement is observed.

QUENCH: A software package for the determination of quenching curves in Liquid Scintillation counting

International Nuclear Information System (INIS)

Cassette, Philippe

2016-01-01

In Liquid Scintillation Counting (LSC), the scintillating source is part of the measurement system and its detection efficiency varies with the scintillator used, the vial and the volume and the chemistry of the sample. The detection efficiency is generally determined using a quenching curve, describing, for a specific radionuclide, the relationship between a quenching index given by the counter and the detection efficiency. A quenched set of LS standard sources are prepared by adding a quenching agent and the quenching index and detection efficiency are determined for each source. Then a simple formula is fitted to the experimental points to define the quenching curve function. The paper describes a software package specifically devoted to the determination of quenching curves with uncertainties. The experimental measurements are described by their quenching index and detection efficiency with uncertainties on both quantities. Random Gaussian fluctuations of these experimental measurements are sampled and a polynomial or logarithmic function is fitted on each fluctuation by χ"2 minimization. This Monte Carlo procedure is repeated many times and eventually the arithmetic mean and the experimental standard deviation of each parameter are calculated, together with the covariances between these parameters. Using these parameters, the detection efficiency, corresponding to an arbitrary quenching index within the measured range, can be calculated. The associated uncertainty is calculated with the law of propagation of variances, including the covariance terms. - Highlights: • The program “QUENCH” is devoted to the interpolation of quenching curves in LSC. • Functions are fitted to experimental data with uncertainties in both quenching and efficiency. • The parameters of the fitting function and the associated covariance matrix are evaluated. • The detection efficiency and uncertainty corresponding to a given quenching index is calculated.

Radioactive flow detectors: liquid or solid scintillators

International Nuclear Information System (INIS)

Reich, A.R.

1983-01-01

During the past five years, two schools of thought have emerged producing two different types of radio-HPLC detectors. Based on the naphthalene-in-the-vial principle, manufacturers have developed heterogeneous scintillation detectors. In these detectors the anthracene or naphthalene crystals are replaced by other scintillators. In order to avoid dead space and turbulence, a narrow diameter tube is used, either straight, or more popularly formed into a coil or a 'U' as the cell. To optimize light transmission to the photomultiplier tubes, mirrors are used. Due to limiting factors in this technique the counting efficiency for tritium is below the 10 percent level. The other school of radio-HPLC detectors based their design on classical liquid scintillation counting technology. In a homogeneous detector, the effluent from the HPLC system is mixed with a suitable liquid scintillator before entering the counting cell. The cell design is typically a flat glass or Teflon coil tightly sandwiched between two photomultiplier tubes, making good optical contact without the use of mirrors. Depending on the chromatographic effluent, 3 H efficiencies between 25 to 50 percent, and 14 C counting efficiencies up to 85 percent can be achieved

Method for determination of radon-222 in water by liquid scintillation counting

International Nuclear Information System (INIS)

Suomela, J.

1993-06-01

The procedure for the determination of radon-222 by liquid scintillation counting is quite specific for this radionuclide. Radon-222 is extracted readily from the water sample by an organic scintillant. The decay products of radon-222 will remain in the water phase whilst radon-222 will be extracted into the organic phase. Before measurement the sample is stored for three hours until equilibrium is reached between radon-222 and its alpha emitting decay products. The alpha activity from radon-222 and its decay products is measured in a liquid scintillation counter

Standarization of Mn-54 by liquid scintillation counting using organic samples of (C8H15 O2)2 Mn-54

International Nuclear Information System (INIS)

1990-01-01

A new method of standardization of Mn 54 by liquid scintillation counting with an organic sample of (C 8 H 15 O 2 ) 2 Mn 54 is described. This procedure shows a good long term stability of samples, over 20 days, and counting efficiencies between 10% and 24% for PCS e INSTAGEL and 10% 32% for a toluene-based scintillator. The discrepancies between experimental and computed values are less that 0,9% for PCS and INSTAGEL and less than 1,2% for Toluene, in the 5-2,5 interval of quenching parameter. The global uncertainty on the activity concentrat-ion of a sample standardized by this method has been lower than 3% (Author)

Combustion water purification techniques influence on OBT analysing using liquid scintillation counting method

Energy Technology Data Exchange (ETDEWEB)

Varlam, C.; Vagner, I.; Faurescu, I.; Faurescu, D. [National Institute for Cryogenics and Isotopic Technologies, Valcea (Romania)

2015-03-15

In order to determine organically bound tritium (OBT) from environmental samples, these must be converted into water, measurable by liquid scintillation counting (LSC). For this purpose we conducted some experiments to determine OBT level of a grass sample collected from an uncontaminated area. The studied grass sample was combusted in a Parr bomb. However usual interfering phenomena were identified: color or chemical quench, chemiluminescence, overlap over tritium spectrum because of other radionuclides presence as impurities ({sup 14}C from organically compounds, {sup 36}Cl as chloride and free chlorine, {sup 40}K as potassium cations) and emulsion separation. So the purification of the combustion water before scintillation counting appeared to be essential. 5 purification methods were tested: distillation with chemical treatment (Na{sub 2}O{sub 2} and KMnO{sub 4}), lyophilization, chemical treatment (Na{sub 2}O{sub 2} and KMnO{sub 4}) followed by lyophilization, azeotropic distillation with toluene and treatment with a volcanic tuff followed by lyophilization. After the purification step each sample was measured and the OBT measured concentration, together with physico-chemical analysis of the water analyzed, revealed that the most efficient method applied for purification of the combustion water was the method using chemical treatment followed by lyophilization.

Role of quenching on alpha/beta separation in liquid scintillation counting for several high capacity cocktails

International Nuclear Information System (INIS)

Pujol, L.; Sanchez-Cabeza, J.-A.

1997-01-01

The optimization of alpha/beta separation in liquid scintillation using pulse shape analysis is convenient for the simultaneous determination of alpha and beta emitters in natural water and other samples. In this work, alpha/beta separation was studied for different scintillant/vial combinations and it was observed that both the optimum pulse shape discrimination level and the total interference value (that is, the summed relative interference between alpha and beta spectra) were dependent on the sample quenching and independent of the scintillant/vial combination. These results provide a simple method for modifying the counting configuration, such as a change in the cocktail, vial or sample characteristics, without the need to perform exhaustive parameter optimizations. Also, it was observed that, for our counting conditions, the combination of Ultima Gold AB scintillation cocktail with Zinsser low diffusion vials presented the lowest total interference, namely 0.94 ± 0.28%, which is insignificant for the counting of environmental samples. (Author)

Assay of /sup 32/Si by liquid scintillation counting

Energy Technology Data Exchange (ETDEWEB)

Cumming, J B [Brookhaven National Lab., Upton, NY (USA)

1983-10-03

Application of the radioactivity of /sup 32/Si to problems of interest in geo- and cosmo-chemistry has been hampered by uncertainties in the half-life of this nuclide. A procedure for the stimulation assay of /sup 32/Si and its /sup 32/P daughter utilizing a liquid scintillation detector in association with a pulse height analyzer is described. The results indicate that /sup 32/Si can be assayed to an accuracy of a few percent by liquid scintillation counting techniques which do not require the preparation of an organic Si derivative. Combination of the mean specific activity with the /sup 32/Si abundance determined by accelerator-based mass spectrometry gave the reported 101+-18 year half-life.

The determination of Pu-241 by liquid scintillation counting in gaseous effluents of an incineration facility, FERAB, and the Karlsruhe Nuclear Reprocessing Plant, WAK

International Nuclear Information System (INIS)

Godoy, J.M.; Schuettelkopf, H.

1983-03-01

Although the concentration of Pu-241 in nuclear fuel to be reprocessed is high, there are only few results published about the emission of Pu-241 with gaseous and liquid effluents. Nearly no information is available, too, about the environmental contamination of nuclear installations by Pu-241. Therefore a procedure was developed to measure Pu-241 by liquid scintillation counting. Sample preparation was performed by electroplating of plutonium on stainless steel planchets. To correct the selfabsorption the linear dependence of counting efficiency in the liquid scintillation counter and the resolution in the α-spectrometer was used. (orig./HP) [de

Comparison of analysis techniques by liquid scintillation and Cerenkov Effect for 40K quantification in aqueous samples

International Nuclear Information System (INIS)

Miranda C, L.; Davila R, J. I.; Lopez del R, H.; Mireles G, F.

2015-09-01

In this work the counting by liquid scintillation and Cerenkov Effect to quantify 40 K in aqueous samples was used. The performance of both techniques was studied by comparing the response of three commercial liquid scintillation OptiPhase HiSafe 3, Ultima Gold Ab and OptiPhase TriSafe, the vial type and presentation conditions of the sample for counting. In liquid scintillation, the ability to form homogeneous mixtures depended on the ionic strength of the aqueous solutions. The scintillator OptiPhase HiSafe 3 showed a greater charge capacity for solutions with high ionic strength (<3.4), while the scintillator OptiSafe TriSafe no form homogeneous mixtures for solutions of ionic strength higher than 0.3. Counting efficiencies for different proportions of sample and scintillator near 100% for the scintillators OptiSafe HiSafe 3 and Ultima Gold Ab were obtained. In the counting by Cerenkov Effect, the efficiency and sensitivity depended of the vial type; polyethylene vials were more suitable for counting that the glass vials. The sample volume had not significant effect on counting efficiency, obtaining an average value of 44.8% for polyethylene vials and 37.3% for glass vials. Therefore, the liquid scintillation was more efficient and sensitive for the measurement of 40 K in aqueous solutions. (Author)

Liquid scintillation counting analysis of cadmium-109

International Nuclear Information System (INIS)

Robinson, M.K.; Barfuss, D.W.

1991-01-01

Recently the authors have used radiolabled cadmium-109 to measure the transport of inorganic cadmium in renal proximal tubules. An anomaly discovered in the liquid scintillation counting analysis of Cd-109 which is not attributable to normal decay; it consists of a significant decrease in the measured count rate of small amounts of sample. The objective is to determine whether the buffer solution used in the membrane transport studies is causing precipitation of the cadmium or whether cadmium is being adsorbed by the glass. It was important to determine whether the procedure could be modified to correct this problem. The problem does not appear to be related to the use of the buffer or to adsorption of Cd onto glass. Correction based on using triated L-glucose in all of these experiments and calculating a correction factor for the concentration of cadmium

Simple analytical technique for liquid scintillation counting of environmental carbon-14 using gel suspension method

International Nuclear Information System (INIS)

Okai, Tomio; Wakabayashi, Genichiro; Nagao, Kenjiro; Matoba, Masaru; Ohura, Hirotaka; Momoshima, Noriyuki; Kawamura, Hidehisa

2000-01-01

A simple analytical technique for liquid scintillation counting of environmental 14 C was developed. Commercially available gelling agent, N-lauroyl-L -glutamic -α,γ-dibutylamide, was used for the gel-formation of the samples (gel suspension method) and for the subsequent liquid scintillation counting of 14 C in the form of CaCO 3 . Our procedure for sample preparation is much simpler than that of the conventional methods and requires no special equipment. Self absorption, stability and reproducibility of gel suspension samples were investigated in order to evaluate the characteristics of the gel suspension method for 14 C activity measurement. The self absorption factor is about 70% and slightly decrease as CaCO 3 weight increase. This is considered to be mainly due to the absorption of β-rays and scintillation light by the CaCO 3 sample itself. No change of the counting rate for the gel suspension sample was observed for more than 2 years after the sample preparation. Four samples were used for checking the reproducibility of the sample preparation method. The same values were obtained for the counting rate of 24 C activity within the counting error. No change of the counting rate was observed for the 're-gelated' sample. These results show that the gel suspension method is appropriate for the 14 C activity measurement by the liquid scintillation counting method and useful for a long-term preservation of the sample for repeated measurement. The above analytical technique was applied to actual environmental samples in Fukuoka prefecture, Japan. Results obtained were comparable with those by other researchers and appear to be reasonable. Therefore, the newly developed technique is useful for the routine monitoring of environmental 14 C. (author)

Liquid scintillation alpha spectrometry techniques

International Nuclear Information System (INIS)

McKlveen, J.W.; McDowell, W.J.

1984-01-01

Accurate, quantitative determinations of alpha emitting nuclides by conventional plate counting methods are difficult, because of sample self-absorption problems in counting and because of non-reproducible losses in conventional sample separation methods. Liquid scintillation alpha spectrometry offers an attractive alternative with no sample self-absorption or geometry problems and with 100% counting efficiency. Sample preparation may include extraction of the alpha emitter of interest by a specific organic phase-soluble compound directly into the liquid scintillation counting medium. Detection electronics use energy and pulse-shape discrimination, to yield alpha spectra without beta and gamma background interference. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium and colonium assay. Possibilities for a large number of other applications exist. Accuracy and reproducibility are typically in the 1% range. Backgrounds of the order of 0.01 cpm are readily achievable. The paper will present an overview of liquid scintillation alpha counting techniques and some of the results achieved for specific applications. (orig.)

Four shells atomic model to computer the counting efficiency of electron-capture nuclides

International Nuclear Information System (INIS)

Grau Malonda, A.; Fernandez Martinez, A.

1985-01-01

The present paper develops a four-shells atomic model in order to obtain the efficiency of detection in liquid scintillation courting, Mathematical expressions are given to calculate the probabilities of the 229 different atomic rearrangements so as the corresponding effective energies. This new model will permit the study of the influence of the different parameters upon the counting efficiency for nuclides of high atomic number. (Author) 7 refs

Determination of plutonium-241 by liquid scintillation counting method and its application to environmental samples

International Nuclear Information System (INIS)

Watanabe, Miki; Amano, Hikaru

1997-03-01

Radionuclides are usually measured by gross counting mode in liquid scintillator counting (LSC) which measures both α and β pulses. This method can easily measure radioactivities, but its background counting is high. Recently reported α-β pulse shape discrimination method (α-β PSD method) in LSC which distinguishes α pulses from β pulses, shows low background counting, so it makes the detection limit lower. The aim of this research is to develop the best method for the determination of 241 Pu which is β-emitter, and Pu isotopes of α-emitters which have long half-lives and stay long in animal body. In this research, two LSC machines was carried out in different scintillators, vial volumes, measurement modes and so on. The following things were found. 1. The liquid scintillator based on naphthalene is proved to be the best separator of α-ray from β-ray, because it acts quickly in energy translation procedure between solvent and aromatic compounds. 2. α-β PSD method makes the background counting rate ten times lower than usual method. It makes the measurement performance better. 3. It is possible to determine 241 Pu in environmental samples around Chernobyl by the combination of LSC and radiochemical separation methods. (author)

Compositions and process for liquid scintillation counting

International Nuclear Information System (INIS)

Kauffman, J.M.

1976-01-01

Liquid scintillation counting compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers, which give homogeneous, monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques, which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous, monophasic appearing aqueous couting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

Compositions and process for liquid scintillation counting

International Nuclear Information System (INIS)

Kauffman, J.M.

1978-01-01

Liquid scintillation compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers, which give homogeneous, monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques, which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous, monophasic appearing aqueous counting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

Chemical and colour quenching in liquid scintillation counting

International Nuclear Information System (INIS)

Grau Malonda, A.; Scott Guilleard, P.E.

1986-01-01

Chemical and colour quenching for H-3 and C-14 was studied. The method includes spectral analysis of colouring agents; methyl red (4'-dimethylamine-azobenzene 2-carboxilic acid) dimethyl yellow (4'-dimethylamine-azobenzene) and melachite green (metane, bis (4'-dimethyl aminophenyl)-(phenyl)). External standard channels ratio was applied for the liquid scintillation counting of samples. The introduction of an isolated external standard seems to be a strong tool for the correction of chemical and colour quenching curves. (author). 10 figs., 12 refs

Chemical and colour quenching in liquid scintillation counting

International Nuclear Information System (INIS)

Scott G, P. E.; Grau M, A.

1987-01-01

Chemical and colour quenching for H-3 and C-14 was studied. The method includes spectral analysis of colouring agents; methyl red, (4'-dimethylamine-azobenzene 2-carboxylic acid) dimethyl yellow (4'-dimethylamine-azobenzene) and malachite green (methane, bis .(4-dimethyl aminophenyl) - (phenyl)). External standard channels ratio was applied for the liquid scintillation counting of samples. The introduction of an isolated external standard seems to be a strong tool for the correction of chemical and colour quenching curves. (Author) 12 refs

An investigation of various wavelength-shifting compounds for improving counting efficiency when 32P-Cerenkov radiation is measured in aqueous samples

International Nuclear Information System (INIS)

Ginkel, G. van

1980-01-01

Various water-soluble wavelength-shifting compounds were investigated to assess their suitability for the improvement of counting efficiency when Cerenkov radiation from phosphorous-32 is measured in a liquid scintillation counter. Of these compounds esculin, β-methyl-umbelliferon and sodium salicylate led to the greatest improvement in counting efficiency. Especially esculin and β-methyl-umbelliferon are fairly stable under a variety of experimental conditions and improve counting efficiencies by a factor of about 1.3 and 1.2 respectively. The use of ethanol as a water-miscible solvent combined with wavelength shifters soluble in both solvents does not improve counting efficiency. (author)

SCINFI, a program to calculate the standardization curve in liquid scintillation counting; SCINFI, un programa para calcular la curva de calibracion eficiencia-extincion en centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Grau Carles, A.; Grau Malonda, A.

1984-07-01

A code, SCINFI, was developed, written in BASIC, to compute the efficiency- quench standardization curve for any radionuclide. The program requires the standardization curve for 3H and the polynomial relations between counting efficiency and figure of merit for both 3H and the problem (e.g. 14{sup C}). The program is applied to the computation of the efficiency-quench standardization curve for 14{sup c}. Five different liquid scintillation spectrometers and two scintillator solutions have bean checked. The computation results are compared with the experimental values obtained with a set of 14{sup c} standardized samples. (Author)

Measurements of 222Rn and 226Ra Levels in environmental samples by using liquid scintillation counter

International Nuclear Information System (INIS)

Moustafa, A.S.

2004-01-01

The advantageous of liquid scintillation counting technique for 6 Ra determination compared with other methods are the high counting efficiency and the easier sample preparation, with no need for sample pre-concentration. In this work, liquid scintillation counting system was used to measure 222 Rn and 226 Ra levels in environmental samples. The liquid scintillation cocktail was prepared in the laboratory and was found efficient for measuring 222 Rn. Soil, sediment and TENORM samples were dried, grind, sieved and added to hydrochloric acid, in a standard scintillation vial, preloaded with the liquid scintillation cocktail. By measuring 222 Rn levels in the prepared vials, at different intervals of time after preparation, 222 Rn and 226 Ra levels were determined

Standardization of iodine-129 by the TDCR liquid scintillation method and 4π β-γ coincidence counting

Science.gov (United States)

Cassette, P.; Bouchard, J.; Chauvenet, B.

1994-01-01

Iodine-129 is a long-lived fission product, with physical and chemical properties that make it a good candidate for evaluating the environmental impact of the nuclear energy fuel cycle. To avoid solid source preparation problems, liquid scintillation has been used to standardize this nuclide for a EUROMET intercomparison. Two methods were used to measure the iodine-129 activity: triple-to-double-coincidence ratio liquid scintillation counting and 4π β-γ coincidence counting; the results are in good agreement.

Measurement of isotopic uranium in water for compliance monitoring by liquid scintillation counting with alpha/beta discrimination

International Nuclear Information System (INIS)

Venso, E.A.S.

1993-01-01

A simple and inexpensive method is described for analysis of uranium (U) activity and mass in water by liquid scintillation counting using α/β discrimination. This method appears to offer a solution to the need for an inexpensive protocol for monitoring U activity and mass simultaneously and an alternative to the potential inaccuracy involved when depending on the mass-to-activity conversion factor or activity screen. U is extracted virtually quantitatively into 20 ml extractive scintillator from a 1-ell aliquot of water acidified to less than pH 2. After phase separation, the sample is counted for a 20-minute screening count with a minimum detection level of 0.27 pCi ell -1 . α-particle emissions from the extracted U are counted with close to 100% efficiency with a Beckman LS6000 LL liquid scintillation counter equipped with pulse-shape discrimination electronics. Samples with activities higher than 10 pCi ell -1 are recounted for 500-1000 minutes for isotopic analysis. Isotopic analysis uses events that are automatically stored in spectral files and transferred to a computer during assay. The data can be transferred to a commercially available spreadsheet and retrieved for examination or data manipulation. Values for three readily observable spectral features can be rapidly identified by data examination and substituted into a simple formula to obtain 234 U/ 238 U ratio for most samples. U mass is calculated by substituting the isotopic ratio value into a simple equation. The utility of this method for the proposed compliance monitoring of U in public drinking water supplies was field tested with a survey of drinking water from Texas supplies that had previously been known to contain elevated levels of gross α activity. U concentrations in 32 samples from 27 drinking water supplies ranged from 0.26 to 65.5 pCi ell -1 , with seven samples exceeding the proposed Maximum Contaminant Level

Radioactivity measurement of barium carbonate [14C] by liquid scintillation counting

International Nuclear Information System (INIS)

Kobayashi, Katsutoshi; Hoizumi, Kiyoshi

1985-03-01

Two methods of sample preparation for the measurement of specific activity of BaCO 3 [ 14 C] by external standard method in liquid scintillation counting were studied. BaCO 3 [ 14 C] was decomposed by perchloric acid solution and generated CO 2 [ 14 C] was absorbed by ethylene glycol monomethyl ether solution of monoethanolamine as the method 1 or aqueous sodium hydroxide as the method 2. In order to prepare the sample solution of adequate radioactivity concentration, these carbonate solutions by the methods 1 and 2 were diluted with the suitable organic solvent and distilled water respectively. One tenth millilitre of these sample solutions was added into 10 ml of PPO-toluene scintillator containing 0.1 ml of monoethanolamine in a counting vial and homogeneously dissolved with ethyl alcohol. The results of the radioactivity measurement of BaCO 3 [ 14 C] based on the different method agreed within 5 % and the counting rate was found to be stable for as long as 7 deays or more. Both methods of preparation are suitable for the routine measurement because of their simplicity and feasibility. In the case of method 2, the liquid radioactive waste is almost inorganic solution and recovery in the form of BaCO 3 [ 14 C] is easily performed, so that this method is very advantageous from the view point of the radioactive waste treatement. (author)

Comparison of accelerator mass spectrometric measurement with liquid scintillation counting measurement for the determination of 14C in environmental samples

International Nuclear Information System (INIS)

Yasuike, Kaeko; Yamada, Yoshimune; Amano, Hikaru

2010-01-01

The concentrations of organically-bound 14 C in tree-ring cellulose of a Japanese Black Pine grown in Shika-machi (37.0 deg. N, 136.8 deg. E) and those of a Japanese Cedar grown in Kanazawa (36.5 deg. N, 136.7 deg. E), Japan, were analyzed for the ring-years from 1989 to 1998 by the accelerator mass spectrometric measurement. The results were compared with those of the same samples analyzed by the liquid scintillation counting measurement to determine the reliability of liquid scintillation counting measurement. An important result of this study is that the sensitivity and reproducibility of accelerator mass spectrometric measurement was almost equal to that of liquid scintillation counting measurement.

Stability and counting losses of Li sup 36 CL samples in liquid scintillation measurements. Evaluacion de la estabilidad y perdidas de recuento de muestras de Li sup 36 CL en medidas por centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Grau, A.; Rodriguez, L.; Los Arcos, J.M.

1990-01-01

A systematic study of several factors concerning the liquid scintillation counting efficiency of Li{sup 36}CL samples in ethanolic solutions has been carried out. The stability of samples containing less than 1.2 Bq/{mu}l of Li{sup 36}Cl in ethanol, added to a toluene-based scintillator is enterely satisfactory. Samples with higher concentration show counting losses than can reach up to 29% of the optimal values along 24 hours. After regeneration of unstable samples by progressive ethanol dilution, the counting efficiency remains always lower than 98% of the best value. Nevertheless the counting rate obtained can be predicted as an exponential function of the dilution degree or activity concentration in the sample. The spectral degradation can be taken into account by defining a parameter, {delta}, wich allows to evaluate the counting loss correction in a sample as a rational function of {delta} (Author)

The study of error for analysis in dynamic image from the error of count rates in Nal (Tl) scintillation camera

International Nuclear Information System (INIS)

Oh, Joo Young; Kang, Chun Goo; Kim, Jung Yul; Oh, Ki Baek; Kim, Jae Sam; Park, Hoon Hee

2013-01-01

This study is aimed to evaluate the effect of T 1/2 upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with '9 9m TcO 4 - of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in χ 2 test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of T 1/2 error from change of gradient with -0.25% to +0.25%, if T 1/2 is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see T 1/2 error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a

Passive neutron coincidence counting with plastic scintillators for the characterization of radioactive waste drums

Energy Technology Data Exchange (ETDEWEB)

Deyglun, C.; Simony, B.; Perot, B.; Carasco, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Saurel, N.; Colas, S. [CEA, DAM, Valduc, F-21120 Is-sur-Tille (France); Collot, J. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Grenoble Alpes, CNRS/IN2P3, Grenoble (France)

2015-07-01

The quantification of radioactive material is essential in the fields of safeguards, criticality control of nuclear processes, dismantling of nuclear facilities and components, or radioactive waste characterization. The Nuclear Measurement Laboratory (LMN) of CEA is involved in the development of time-correlated neutron detection techniques using plastic scintillators. Usually, 3He proportional counters are used for passive neutron coincidence counting owing to their high thermal neutron capture efficiency and gamma insensitivity. However, the global {sup 3}He shortage in the past few years has made these detectors extremely expensive. In addition, contrary to {sup 3}He counters for which a few tens of microseconds are needed to thermalize fast neutrons, in view to maximize the {sup 3}He(n,p){sup 3}H capture cross section, plastic scintillators are based on elastic scattering and therefore the light signal is formed within a few nanoseconds, correlated pulses being detected within a few dozen- or hundred nanoseconds. This time span reflects fission particles time of flight, which allows reducing accordingly the duration of the coincidence gate and thus the rate of random coincidences, which may totally blind fission coincidences when using {sup 3}He counters in case of a high (α,n) reaction rate. However, plastic scintillators are very sensitive to gamma rays, requiring the use of a thick metallic shield to reduce the corresponding background. Cross talk between detectors is also a major issue, which consists on the detection of one particle by several detectors due to elastic or inelastic scattering, leading to true but undesired coincidences. Data analysis algorithms are tested to minimize cross-talk in simultaneously activated detectors. The distinction between useful fission coincidences and the correlated background due to cross-talk, (α,n) and induced (n,2n) or (n,n'γ) reactions, is achieved by measuring 3-fold coincidences. The performances of a

The measurement of Rn-222 in drinking water by low-level liquid scintillation counting

International Nuclear Information System (INIS)

Barnett, J.M.; McKlveen, J.W.

1991-01-01

Radon-222 has consistently been found in well water. The research objectives are to establish a method to collect well water and to measure the Rn in ground water using liquid scintillation (LS) counting. Water is collected at the well head while the well is pumping. The water is adjusted to a slow, non-aerated, steady flow through a clear tube, and a 437 mL (16 oz) glass bottle is filled. The sample is tightly capped after a high meniscus has developed. In the laboratory, standard 22 mL LS glass vials are filled with 10 mL of a toluene based mineral oil LS cocktail. Then, two 5 mL sample aliquots are pipetted into the vial. Vials are capped tightly, shaken vigorously, and placed in the LS counter. Secular equilibrium is established in approximately 3.5 hours, after which samples are counted for 100 minutes each. Quality assurance and control is performed weekly on the LS counter's electronics, spectral window, counting efficiency, and background. The counting efficiency ranges between 315-345 percent depending on the chosen spectral window. The average background is about 6 cpm. A total of 28 wells were tested for Rn in the Carefree-Cave Creek, Arizona, USA area, and 12 wells were selected, each over 50 Bq/L (1,350 pCi/L), for an extended 6 month period. The area's average Rn concentration was found to be 46.5 Bq/L (1,255 pCi/L); it is a geometric mean. The associated estimated lung dose is 1.13 mSv/a

Upgradation of automatic liquid scintillation counting system

International Nuclear Information System (INIS)

Bhattacharya, Sadhana; Behere, Anita; Sonalkar, S.Y.; Vaidya, P.P.

2001-01-01

This paper describes the upgradation of Microprocessor based Automatic Liquid Scintillation Counting systems (MLSC). This system was developed in 1980's and subsequently many systems were manufactured and supplied to Environment Survey labs at various Nuclear Power Plants. Recently this system has been upgraded to a more sophisticated one by using PC add-on hardware and developing Windows based software. The software implements more intuitive graphical user interface and also enhances the features making it comparable with commercially available systems. It implements data processing using full spectrum analysis as against channel ratio method adopted earlier, improving the accuracy of the results. Also it facilitates qualitative as well as quantitative analysis of the β-spectrum. It is possible to analyze a sample containing an unknown β-source. (author)

Neutron detection and multiplicity counting using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array

International Nuclear Information System (INIS)

Miller, M.C.

1998-03-01

Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ( 10 B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where 3 He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector's response and filtering based on the presence of a simultaneous energy deposition corresponding to the 10 B(n,alpha) reaction products in the plastic scintillator (93 keV ee ) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including 137 Cs, 54 Mn, AmLi, and 252 Cf. Results of this study indicate that a neutron-capture probability of ∼10% and a die-away time of ∼10 micros are possible with a 4-detector array with a detector volume of 1600 cm 3 . Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 micros are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this investigation are encouraging and may lead to a new class of high-efficiency

Scintillation counter based radiation dosimeter

International Nuclear Information System (INIS)

Shin, Jeong Hyun

2009-02-01

The average human exposure per year is about 240mrem which is come from Radon and human body and terrestrial and cosmic radiation and man-made source. Specially radiation exposure through air from environmental radiation sources is 80mrem/yr(= 0.01mR/hr) which come from Terrestrial and cosmic radiation. Radiation dose is defined as energy deposit/mass. There are two major methods to detect radiation. First method is the energy integration using Air equivalent material like GM counter wall material. Second method is the spectrum to dose conversion method using NaI(Tl), HPGe. These two methods are using generally to detect radiation. But these methods are expensive. So we need new radiation detection method. The research purpose is the development of economical environmental radiation dosimeter. This system consists of Plastic/Inorganic scintillator and Si photo-diode based detector and counting based circuitry. So count rate(cps) can be convert to air exposure rate(R/hr). There are three major advantages in this system. First advantages is no high voltage power supply like GM counter. Second advantage is simple electronics. Simple electronics system can be achieved by Air-equivalent scintillation detector with Al filter for the same detection efficiency vs E curve. From former two advantages, we can know the most important advantages of the this system. Third advantage is economical system. The price of typical GM counter is about $1000. But the price of our system is below $100 because of plastic scintillator and simple electronics. The role of scintillation material is emitting scintillation which is the flash of light produced in certain materials when they absorb ionizing radiation. Plastic scintillator is organic scintillator which is kind of hydrocarbons. The special point are cheap price, large size production(∼ton), moderate light output, fast light emission(ns). And the role of Al filter is equalizing counting efficiency of air and scintillator for

The efficacy of biodegradable liquid scintillation counting cocktails

International Nuclear Information System (INIS)

Klein, R.C.; Gershey, E.L.

1990-01-01

Liquid scintillation counting (LSC) waste once accounted for ∼50% of the low-level radioactive wastes generated by academic and biomedial research. Strict regulations banning the land burial of organic liquids led the U.S. Nuclear Regulatory Commission to deregulate very low level LSC waste (10CFR20.306 of the Code of Federal Regulations) in 1981. Today, LSC waste containing ≤0.05 μCi/ml of 3 H or 14 C is generally incinerated as flammable liquid. Several manufacturers are now offering cocktails that contain long-chain and multiringed aromatic compounds that have not been identified as hazardous by the Environmental Protection Agency (EPA) under the Resource Conservation and Recovery Act (40CFR261) or the Clean Water Act (40CFR122). In addition to lower toxicity and higher flash points than their predecessors, these new cocktails are being advertised as biodegradable. Simple exclusion from the relatively short EPA lists of hazardous chemicals, however, may only reflect insufficient study. Five cocktail solvent families were identified by gas chromatography (GC) and GC/mass spectrometry: meta- and ortho-xylenes, trimethylbenzene isomers, linear alkylbenzenes, 1-phenyl-1-(3,4-xylyl)-ethane, and diisopropylnaphthalene. Cocktail efficiencies were determined for tritiated samples commonly found in biomedical research by the internal standard method

The determination of Pu-241 by liquid scintillation counting in liquid effluents of the Karlsruhe Nuclear Research Center

International Nuclear Information System (INIS)

Godoy, J.M.; Schuettelkopf, H.; Pimpl, M.

1983-04-01

A procedure was developed to measure Pu-241 by liquid scintillation counting. Sample preparation was performed by electroplating of plutonium on stainless steel planchets. To correct the selfabsorption, the linear dependence of counting efficiency in the liquid scintillation counter from the resolution in the alpha spectrometer was used. Pu-238, Pu-239+240 and Pu-241 were measured in the liquid effluents of the Karlsruhe Nuclear Research Center (KfK). The concentrations in monthly mixed samples ranged from 0.07 until 46 nCi Pu-238/m 3 , from 0.13 until 2.1 nCi Pu-239+240/m 3 and from 25 until 190 nCi Pu-241/m 3 . Between 5.4% and 41% of the plutonium content of the KfK waste water are released to the River Old Rhine. The values for the activity ratio Pu-238/Pu-239+240 are between 0.39 and 1.1 and for Pu-241/Pu-239+240 are between 11 and 300. The mean value for Pu-241/Pu-239+240 is 61. The dose exposure of the environmental population of the Karlsruhe Nuclear Research Center caused by released Pu-241 is negligible low. (orig./HP) [de

Determination of 226Ra and 224Ra in drinking waters by liquid scintillation counting

International Nuclear Information System (INIS)

Manjon, G.; Vioque, I.; Moreno, H.; Garcia-Tenorio, R.; Garcia-Leon, M.

1997-01-01

A method for the determination of Ra-isotopes in water samples has been developed. Ra is coprecipitated with Ba as sulphate. The precipitate is then dissolved with EDTA and counted with a liquid scintillation system after mixing with a scintillation cocktail. The study of the temporal evolution of the separated activity gives the isotopic composition of the sample, i.e. the 224 Ra and 226 Ra contribution to the total activity. The method has been applied to some Spanish drinking waters. (author)

Study of alternative methods for the management of liquid scintillation counting wastes

International Nuclear Information System (INIS)

Roche-Farmer, L.

1980-02-01

The Nuclear Engineering Waste Disposal Site in Richland, Washington, is the only radioactive waste disposal facility that will accept liquid scintillation counting wastes (LSCW) for disposal. That site is scheduled to discontinue receiving LSCW by the end of 1982. This document explores alternatives presently available for management of LSCW: evaporation, distillation, solidification, conversion, and combustion

Imaging performance comparison between a LaBr3: Ce scintillator based and a CdTe semiconductor based photon counting compact gamma camera.

Science.gov (United States)

Russo, P; Mettivier, G; Pani, R; Pellegrini, R; Cinti, M N; Bennati, P

2009-04-01

The authors report on the performance of two small field of view, compact gamma cameras working in single photon counting in planar imaging tests at 122 and 140 keV. The first camera is based on a LaBr3: Ce scintillator continuous crystal (49 x 49 x 5 mm3) assembled with a flat panel multianode photomultiplier tube with parallel readout. The second one belongs to the class of semiconductor hybrid pixel detectors, specifically, a CdTe pixel detector (14 x 14 x 1 mm3) with 256 x 256 square pixels and a pitch of 55 microm, read out by a CMOS single photon counting integrated circuit of the Medipix2 series. The scintillation camera was operated with selectable energy window while the CdTe camera was operated with a single low-energy detection threshold of about 20 keV, i.e., without energy discrimination. The detectors were coupled to pinhole or parallel-hole high-resolution collimators. The evaluation of their overall performance in basic imaging tasks is presented through measurements of their detection efficiency, intrinsic spatial resolution, noise, image SNR, and contrast recovery. The scintillation and CdTe cameras showed, respectively, detection efficiencies at 122 keV of 83% and 45%, intrinsic spatial resolutions of 0.9 mm and 75 microm, and total background noises of 40.5 and 1.6 cps. Imaging tests with high-resolution parallel-hole and pinhole collimators are also reported.

Analytical method of Kr-85 determination, using cryogenic concentration and separation and liquid scintillation counting

International Nuclear Information System (INIS)

Heras Iniquez, M.C.; Perez Garcia, M.M.; Grau Malonda, A.

1983-01-01

The method used in the Laboratory of the JEN for the determination of Kr-85 levels in gaseous effluents of nuclear power and in the atmosphere is described. Samples of air, collected in metallic cylinders, are introduced into a gas-solid chromatographic separation system which resolves Kr from the other air components. The separated Kr ia dissolved in a toluene based scintillation cocktail, and the Kr-85 content is determined by liquid scintillation counting. (Author)

A scheme for recycling of used liquid scintillation counting cocktail for tritium analysis

International Nuclear Information System (INIS)

Gocher, A.K.; Tailor, S.P.; Tiwari, S.N.; Ravi, P.M.; Tripathi, R.M.

2018-01-01

Ultima Gold LLT TM is a ready to use scintillation cocktail used for estimation of tritium activity in various water sample collected from Rawatbhata Rajasthan Site environment up to 30 km radial distance. The present study explores the possibility of re-using the cocktail used in non detect (BDL) samples for counting of high active samples. Results of tritium standard counted with used cocktail (UC) was within ±10 % variation w.r.t fresh Ultima gold scintillation cocktail. Also results of high active samples prepared using 20 ml Used Cocktail (UC) and 1 ml sample (20 ml UC: 1ml aq. sample) were found in the range -7% to +11.1% w.r.t same sample prepared using fresh Ultima Gold. Used cocktail (UC) can be reused for tritium activity estimation of high active samples. Re-using of used cocktail will ultimately reduce the cocktail consumption, reduce the operational cost and reduce the quantity of waste cocktail disposal to the environment

Measurement of light emission in scintillation vials

International Nuclear Information System (INIS)

Duran Ramiro, M. Teresa; Garcia-Torano, Eduardo

2005-01-01

The efficiency and energy resolution of liquid scintillation counting (LSC) systems are strongly dependent on the optical characteristics of scintillators, vials, and reflectors. This article presents the results of measurements of the light-emission profile of scintillation vials. Two measurement techniques, autoradiographs and direct measurements with a photomultiplier tube, have been used to obtain light-emission distribution for standard vials of glass, etched glass and polyethylene. Results obtained with both techniques are in good agreement. For the first time, the effect of the meniscus in terms of light contribution has been numerically estimated. These results can help design LSC systems that are more efficient in terms of light collection

Liquid emulsion scintillators which solidify for facile disposal

International Nuclear Information System (INIS)

O'Brien, R.E.; Krieger, J.K.

1981-01-01

A liquid organic scintillation cocktail is described which counts solutions of radiolabelled compounds containing up to ten % by volume of water with high efficiency and is readily polymerizable to a solid for easy disposal. The cocktail comprises a polymerizable organic solvent, a solubilizing agent, an intermediate solvent, and an organic scintillator. A method of disposing of liquid organic scintillation cocktail waste and a kit useful for practising the method are also described. (U.K.)

Low level scintillation counting of 239Pu

International Nuclear Information System (INIS)

Fueloep, M.; Minarik, F.; Cierna, V.

1984-01-01

For measuring the content of 239 Pu in samples taken from the working or living environment, methods should be used which are sufficiently sensitive for determining activities of the order of 10 -3 Bq. It is useful to use liquid scintillators for reasons of their 4π geometry and the exclusion of kinetic energy losses of particles detected in the sample and on the path between the sample and the detector. The method of background discrimination according to pulse shape may be used to suppress gamma background in the area of alpha particle peaks to the level 2.5x10 -4 s -1 . The diagram is given of electronic circuits for shape discrimination. The scintillator used was a SLS-31 with a PBD activator, a POPOP spectrum shifter and a mixture of solvents: toluene, dioxane and methanol. The efficiency of 239 Pu alpha particle detection is estimated at 78% and may further be improved by improving shape discrimination. (M.D.)

Advanced Multilayer Composite Heavy-Oxide Scintillator Detectors for High Efficiency Fast Neutron Detection

Science.gov (United States)

Ryzhikov, Vladimir D.; Naydenov, Sergei V.; Pochet, Thierry; Onyshchenko, Gennadiy M.; Piven, Leonid A.; Smith, Craig F.

2018-01-01

We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium - designated as ZEBRA - serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron

Study on efficiency calibration of tritium in liquid scintillation spectrometry

International Nuclear Information System (INIS)

Zhai Xiufang; Wang Yaoqin; Li Weiping; Liang Wei; Xu Hui; Zhang Ruirong

2014-01-01

The method for efficiency calibration of tritium sample in liquid scintillation spectrometry was presented. The quenching effects from different chemical quenchers (Acidbase, CH_3NO_2, CCl_4, CH_3COCH_3) and color quencher (Na_2CrO_4) were studied. For each quencher, the methods of sample channel ratio (SCR), spectrum index of the sample (SIS) and spectral quenching parameter of the external standard (SQP (E)) were used for efficiency calibration respectively, and three methods were compared. The results show that the quenching from the various chemical quencher can be unified for one chemical quenching for efficiency calibration. There is great difference in the correction curves of chemical quenching and color quenching, and the fact is independent of the used efficiency calibration method. The SCR method is not advantageous for the tritium sample with low radioactivity or strong quenching. The SQP (E) method is independent of the sample count rate, and it is especially suitable for the efficiency calibration of low radioactivity tritium. The SIS method can be used for samples with high radioactivity. The accurate efficiency calibration for various quenching can be carried out by combining the SIS method and the SQP (E) method. (authors)

Efficiency and yield spectra of inorganic scintillates

International Nuclear Information System (INIS)

Rodnyi, P.A.

1998-01-01

Recent developments in the field of energy loss in inorganic scintillators are reviewed. The main parameters, which control the fundamental limit of the scintillator energy efficiency, are determined. It is shown that together with simple cascade processes one should take into account the production of plasmons to estimate the energy efficiency of scintillators or other phosphors excited by an ionizing radiation. Core-to-valence luminescence related to 5pCs→3pCl transitions is investigated in some chlorides: CsCl, KCl, RbCl, NaCl, KCaCl 3 , RbCaCl 3 . The yield spectra of the crystals in the VUV and X-ray regions are also studied. It is shown that the 4pRb-core states are involved in the process of creation of holes in the 5pCs-core band in Rb-based crystals. The formation of holes in the potassium core band acts as a competing process and suppresses the radiative core-to-valence transitions

Development of a high-count-rate neutron detector with position sensitivity and high efficiency

International Nuclear Information System (INIS)

Nelson, R.; Sandoval, J.

1996-01-01

While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled 3 He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source

An investigation of various wavelength-shifting compounds for improving counting efficiency when 32P-cerenkov radiation is measured in aqueous samples

NARCIS (Netherlands)

Ginkel, G. van

Various water-soluble wavelength-shifting compounds were investigated to assess their suitability for the improvement of counting efficiency when erenkov radiation from phosphorous-32 is measured in a liquid scintillation counter. Of these compounds esculin, β-methyl-umbelliferon and sodium

A new analytical method for 32P. Liquid scintillation counting with solvent extraction

International Nuclear Information System (INIS)

Liyanage, J.A.; Yonezawa, C.

2003-01-01

Trace determination of phosphorus has been studied using neutron activation analysis. Radioactivity of 32 P in tri-n-octylamine phosphomolybdate complex was measured using liquid scintillation counting by extracting the complex into xylene. Phosphorus can be quantitatively determined from 16.7 to 600 μg/10 ml by using the radiochemical analysis method described. (author)

Liquid scintillation systems and apparatus for measuring high-energy radiation emitted by samples in standard laboratory test tubes

International Nuclear Information System (INIS)

Benvenutti, R.A.

1976-01-01

Liquid scintillation detection system employs improved sample holders in which the cap of a glass vial is provided with a well for receiving a standard laboratory test tube containing a radioactive sample. The well is immersed in a liquid scintillator in the vial, the scintillator containing lead acetate solution to enhance its efficiency. A commercially available beta-counting liquid scintillation apparatus is modified to provide gamma-counting with the improved sample holders

An efficient energy response model for liquid scintillator detectors

Science.gov (United States)

Lebanowski, Logan; Wan, Linyan; Ji, Xiangpan; Wang, Zhe; Chen, Shaomin

2018-05-01

Liquid scintillator detectors are playing an increasingly important role in low-energy neutrino experiments. In this article, we describe a generic energy response model of liquid scintillator detectors that provides energy estimations of sub-percent accuracy. This model fits a minimal set of physically-motivated parameters that capture the essential characteristics of scintillator response and that can naturally account for changes in scintillator over time, helping to avoid associated biases or systematic uncertainties. The model employs a one-step calculation and look-up tables, yielding an immediate estimation of energy and an efficient framework for quantifying systematic uncertainties and correlations.

High efficiency scintillation detectors

International Nuclear Information System (INIS)

Noakes, J.E.

1976-01-01

A scintillation counter consisting of a scintillation detector, usually a crystal scintillator optically coupled to a photomultiplier tube which converts photons to electrical pulses is described. The photomultiplier pulses are measured to provide information on impinging radiation. In inorganic crystal scintillation detectors to achieve maximum density, optical transparency and uniform activation, it has been necessary heretofore to prepare the scintillator as a single crystal. Crystal pieces fail to give a single composite response. Means are provided herein for obtaining such a response with crystal pieces, such means comprising the combination of crystal pieces and liquid or solid organic scintillator matrices having a cyclic molecular structure favorable to fluorescence. 8 claims, 6 drawing figures

The determination of 14CO2 in breath by liquid scintillation counting

International Nuclear Information System (INIS)

Ozker, K.; East, B.W.; Boddy, K.

1977-03-01

A sensitive method of sampling and measuring the specific activity of 14 CO 2 in expired breath in order to evaluate the metabolic pathways of 14 C-labelled compounds has been devised. 14 CO 2 is blown through a short plastic tube, attached to a drier, into a scintillation vial containing hyamine hydroxide and ethanol. 14 CO 2 was generated to the end-point of neutralization of hyamine hydroxide, indicated by the decolourisation of phenolphthalein. 14 CO 2 was counted after mixing the hyamine hydroxide and ethanol with 15ml toluene scintillation solution. The specific activity of 14 CO 2 from the samples was compared with that of solutions of known activity. The method is sensitive for clinical applications and can be performed at a patient's bedside. (U.K.)

Counting statistics in low level radioactivity measurements fluctuating counting efficiency

International Nuclear Information System (INIS)

Pazdur, M.F.

1976-01-01

A divergence between the probability distribution of the number of nuclear disintegrations and the number of observed counts, caused by counting efficiency fluctuation, is discussed. The negative binominal distribution is proposed to describe the probability distribution of the number of counts, instead of Poisson distribution, which is assumed to hold for the number of nuclear disintegrations only. From actual measurements the r.m.s. amplitude of counting efficiency fluctuation is estimated. Some consequences of counting efficiency fluctuation are investigated and the corresponding formulae are derived: (1) for detection limit as a function of the number of partial measurements and the relative amplitude of counting efficiency fluctuation, and (2) for optimum allocation of the number of partial measurements between sample and background. (author)

Influence of atomic and nuclear constants on the counting efficiency for 55{sup F}e in liquid scintillators; Influencia de los parametros atomicos y nucleares en la calibracion de 55{sup F}e mediante centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Fernandez, A.; Grau, A.; Arcos, J. M. los

1985-07-01

In this paper one considers the influence of the different parameters on the determination of the uncertainty of the detection efficiency for 55{sup F}e when the counting technique of liquid scintillation is applied. The following parameters are considered: the relative probabilities of X and Auger emission so as their corresponding energies, the fluorescence yields W{sup K} and W{sup L}, and the non-interaction probabilities of the emitted X photons. (Author) 11 refs.

Low-level measurements by liquid scintillation counting

International Nuclear Information System (INIS)

Schoenhofer, F.

1991-01-01

Liquid scintillation counting has become a convenient tool for analysis of many beta- and alpha-emitters even in ultra low-level concentration ranges. Extremely low background is achieved in a commercially available counter by an active shielding and heavy lead shielding. Thus special time saving radiochemical separation processes could be designed. Extremely simple sample preparation techniques can be used. Counting time can be reduced and sample throughput enhanced. Also precision can be enhanced. From the author's research, several applications are discussed. They include: tritium in water without enrichment, tritium in urine (excretion analysis), carbon-14 in samples like alcohol or vinegar, Rn-222 in water and air, even gaseous Kr-85. A simple and fast method for Sr-90 in environmental samples and food has been developed and the Ra-226-concentration in water can be measured as low as 30 mBq/l without any chemical separation or enrichment. The instrument has been used successfully for screening purposes after the Chernobyl accident as well as for monitoring groundwater after a large scale contamination in Lower Austria. Using a 'gross-beta-measurement' effluents from a nuclear installation are monitored, clearly showing advantages over traditional methods. α-β-discrimination reduces the background for alpha emitters to practically zero. Examples from the determination of Ra-226 in water are shown

Alternating sample changer and an automatic sample changer for liquid scintillation counting of alpha-emitting materials

International Nuclear Information System (INIS)

Thorngate, J.H.

1977-08-01

Two sample changers are described that were designed for liquid scintillation counting of alpha-emitting samples prepared using solvent-extraction chemistry. One operates manually but changes samples without exposing the photomultiplier tube to light, allowing the high voltage to remain on for improved stability. The other is capable of automatically counting up to 39 samples. An electronic control for the automatic sample changer is also described

Standardization of I-125 solution by extrapolation of an efficiency wave obtained by coincidence X-(X-γ) counting method

International Nuclear Information System (INIS)

Iwahara, A.

1989-01-01

The activity concentration of 125 I was determined by X-(X-α) coincidence counting method and efficiency extrapolation curve. The measurement system consists of 2 thin NaI(T1) scintillation detectors which are horizontally movable on a track. The efficiency curve is obtained by symmetricaly changing the distance between the source and the detectors and the activity is determined by applying a linear efficiency extrapolation curve. All sum-coincidence events are included between 10 and 100 KeV window counting and the main source of uncertainty is coming from poor counting statistic around zero efficiency. The consistence of results with other methods shows that this technique can be applied to photon cascade emitters and are not discriminating by the detectors. It has been also determined the 35,5 KeV gamma-ray emission probability of 125 I by using a Gamma-X type high purity germanium detector. (author) [pt

Liquid Scintillation Counting Standardization of {sup 2}2NaCl by te CIEMAT/NIST method; Calibracion por Centelleo Liquido del ''22NaCl, mediante el metodo CIEMAT/NIST

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1995-07-01

We describe a procedure for preparing a stable solution of ''22NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4 % and an overall uncertainty of 0.35 %. (Author) 4 refs.

The measurement of 222Rn in drinking water by low-level liquid scintillation counting

International Nuclear Information System (INIS)

Barnett, J.M.; McKlveen, J.W.

1992-01-01

Radon-222 (Rn) has universally been found in well water. Non-stagnant ground water is collected at the well head while the well is pumping. The water is adjusted to a slow, non-aerated, steady flow through a clear tube, and a 500 ml glass bottle is filled. The sample is tightly capped after a high meniscus has developed. In the laboratory, standard 22 ml glass vials are filled with 10 ml of a toluene based mineral oil LS cocktail. Then, two 5 ml sample aliquots are pipetted into the vial. Vials are capped tightly, shaken vigorously, and placed in the liquid scintillation (LS) counter. Secular equilibrium is established in approximately 4 hours, after which samples are counted for 100 minutes each. The counting efficiency for Rn and progeny ranges between 315 to 345 percent depending on the chosen spectral window. The average background is about 6 cpm. A total of 28 wells were tested for Rn in the Carefree-Cave Creek, Arizone, USA area. The area's geometric average Rn concentration was found to be 46.5 Bq*1 -1 . The associated estimated lung dose is 0.51 mSv*y -1 . (author) 8 refs.; 1 fig.; 1 tab

Optimization of plastic scintillator thicknesses for online beta/gamma detection

Directory of Open Access Journals (Sweden)

Pourtangestani K.

2012-04-01

Full Text Available For efficient beta detection in a mixed beta gamma field, Monte Carlo simulation models have been built to optimize the thickness of a plastic scintillator, used in a whole body monitor. The simulation has been performed using the MCNP/X code for different thicknesses of plastic scintillator from 150 μm to 600 μm. The relationship between the thickness of the scintillator and the efficiency of the detector has been analyzed. For 150 μm thickness, an experimental investigation has been conducted with different beta sources at different positions on the scintillator and the counting efficiency of the unit has been measured. Evaluated data along with experimental ones have been discussed. A thickness of 300 μm to 500 μm has been found to be the optimum thickness for high efficiency beta detection in the presence of low energy gamma-rays.

Spectrum library concept and pulse shape analysis in liquid scintillation counting

Energy Technology Data Exchange (ETDEWEB)

Kaihola, L [Wallac Oy, Turku (Finland)

1997-03-01

Wallac introduced in 1990 a new absolute liquid scintillation counting (LSC) method, Digital Overlay Technique (DOT) to correct for quench. This method allows quantization of multilabel samples by referring to library spectra which are generated against chemical and color quench indices at the factory. The libraries can further be expanded to any beta emitter by user with a method called fine tuning, which can be carried out even with a single sample. Spectrum libraries are created over the whole spectrum range of the radionuclide and allow automatic identification of a single label beta emitting radionuclide, called Easy Count method. Another improvement in LSC is commercial introduction of Pulse Shape Analysis (PSA) in 1986 by Wallac. This method recognizes alpha particle decay by pulse shape and leads to excellent sensitivity in alpha counting because most of the background signal in LSC comprises of short or beta like pulses. PSA detects alpha events in the presence of high excess of beta activity over alphas, up to a ratio 100000 to 1. (orig.)

Preparation of manganese salts of carboxylic acids labelled with ''54Mn and comparison with ''54 MnCl2 in liquid scintillation counting

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Arcos Merino, J. M. los; Grau Malonda, A.

1992-01-01

Procedures for liquid scintillation sample preparation of manganese dimethylbutirate, decanoate and palmitate, labelled with 54 Mn are described. their quenching effect, spectral evolution and counting stability along several weeks are analysed in liquid scintillation measurements with Toluene. HISafe II. PCS, instagel. Dioxane-naphtalene and Toluene-alcohol. For comparison, Inorganic 54 MnCl-2 samples are also studied, resulting in acceptable counting stability but showing greater quenching and signs of little spectral degradation against the organic samples. (Author)

Determination of radon in indoor air in Quebec by liquid scintillation counting in ortho-xylene

Energy Technology Data Exchange (ETDEWEB)

Chah, B; Zikovsky, L; Champagne, P [Ecole Polytechnique, Montreal, PQ (Canada)

1992-01-01

A new method for the determination of radon in air has been developed. it is based on low temperature absorption of radon in ortho-xylene followed by liquid scintillation counting. The method is reasonably fast and sensitive enough to analyse air without precipitation. The detection limit at the 95% confidence level for a 20 l air sample and 1 h counting time is 2 mBql{sup -1}. Radon concentrations measured in indoor air in Quebec varied from 7 to 162 mBql{sup -1}. (Author).

Standardization of 40 K by liquid scintillation counting. Determination of the half-life

International Nuclear Information System (INIS)

Grau Carles, A.; Grau Malonda, A.

1997-01-01

The relative abundance of the natural radioisotope ''40 K in environmental samples frequently generates interferences in low activity measurements. In the present study we propose the determination of ''40 K by the CIEMAT/NIST method. On this context, the verification of ''40 K half-life is required. We present a half-life value obtained by liquid scintillation counting in excellent agreement with those reported in the literature. (Author)

Preparatory on manganose salts of carboxilic acids labelled with 54Mn and comparison with 54MnCl2 in liquid scintillation counting

International Nuclear Information System (INIS)

Rodriguez, L.; Los Arcos, J.M.; Grau, A.

1992-01-01

Procedures for scintillation sample preparation of manganose dimethylbutirate, decanoate and palmitate, labelled with 54 Mn are described. Their quenching effect, spectral evolution and counting stability along several weeks are analysed in liquid scintillation measurements with Toluene, HlSafe II, PCS, Instagel, Dioxane-naphtalene and Toluene-alcohol. For comparison, inorganic 54 MnCl 2 samples are also studied, resulting in acceptable counting stability but showing greater quenching and signs of little spectral degradation against the organic samples. (author) 14 fig. 15 ref

Quantitative determination of 14C(-)-epicatechin and 14C-rutin on the Uncaria plant by a two-step heterogeneous thin-layer chromatographic-liquid scintillation counting procedure

International Nuclear Information System (INIS)

Das, N.P.; Law, K.H.

1987-01-01

A simple, rapid, precise and relatively inexpensive thin-layer chromatographic method coupled to heterogeneous liquid scintillation counting procedure was used for the quantitation of radioactivity of biologically synthesized ( 14 C) flavonoids and other phenolic plant constituents. The two flavonoids, namely ( 14 C) rutin and ( 14 C) (-) -epicatechin, extracted from the plant Uncaria elliptica Roxb were separated on plastic thin-layer plates coated with silica gel using the two solvent systems : acetonitrile-acetic acid-water (8.5:0.5:1.5) and ethyl acetate-acetic acid-water (3:1:3). The respective spots on the plates that corresponded to the two flavonoids were cut out and eluted with 3 ml aliquots of methanol followed by direct addition of scintillation flour. This method gave 99 +- 2 per cent of the total count indicating the excellent elution procedure. The results were reproducible and showed linearity over the range of 0 - 35000 dpm. The elution efficiency by several other organic solvents were also investigated. (author). 19 refs., 4 tables

Planktonic primary production evaluation by means of the 14C method with liquid scintillation counting

International Nuclear Information System (INIS)

Frangopol, T.P.; Bologa, S.A.

1979-05-01

Preliminary results on the planktonic primary production obtained for the first time with the 14 C method off the Romanian Black Sea coast (1977, 1978) and in the Sinoe, Mamaia and Bicaz lakes (1978) are presented, along with a review of this method with special reference to liquid scintillation counting. 140 Refs. (author)

Quality control of radiation counting systems and measurement of minimum detectable activity

International Nuclear Information System (INIS)

Song, Byoung Chul; Han, Sung Sim; Kim, Young Bok; Jee, Kwang Yong; Sohn, Se Chul

2004-01-01

Various radiation counters have been using to determine radioactivity of radwastes for disposal. A radiation counting system was set up using a radiation detector chosen in this study and its stability was investigated through the periodic determination of background and counting efficiencies in accordance with a quality control program to increase the confidence level. The average background level for the γ-spectrometer was 1.59 cps and the average counting level for the standard sample was 45248 dps within 20 confidence levels. The average alpha background level for the low background α/β counting system was 0.31 cpm and the efficiency for alpha counting was 34.38 %. The average beta background level for the α/β counting system was 1.30 cpm and the efficiency for beta counting was 46.5%. The background level in the region of 3H and 14C for the liquid scintillation counting system was 2.52 and 3.31 cpm and the efficiency for alpha counting was 58.5 and 95.6%, respectively. The minimum detectable activity for the γ-spectrometer was found to be 3.2 Bq/mL and 3.8 Bq/mL for the liquid scintillation counter, and 20.5 and 23.0 Bq/mL, respectively for the α and β counting system

Review of the evolution of safety, ecological and economical aspects of liquid scintillation counting materials and techniques

International Nuclear Information System (INIS)

Kalbhen, D.A.

1983-01-01

The wide applicability of liquid scintillation techniques for counting weak β-emitters and other radionuclides has led to the daily use of a large number of liquid scintillation counter instruments in research and control laboratories. Of the solvents used in liquid scintillators, xylene, toluene and trimethyl benzene are most common. To a minor extent, dioxane, methylglycol, ethanol and methanol are also used. The estimated annual total volume is around 2-3 million liters of scintillation cocktails. The present situation demonstrates a problem in laboratory safety and concomitant cost for waste treatment, usually not recognized. The use and handling of these inflammable and irritant solvents can induce certain risks to personnel and laboratory safety. A significant reduction of the ecological and health risks is important. In recent years, some progress has been made by using smaller volumes and smaller sizes of vials. The introduction of non-flammable scintillator solvents, which do not penetrate through polyethylene vials and do not escape into the laboratory atmosphere, also adds to the safety process

Preparation of 45Ca(HDEHP)n and (CaH1502)2 samples for liquid scintillation counting, compared to 45caCl2 results

International Nuclear Information System (INIS)

Rodriguez, L.; Arcos, J. M. los; Grau Malonda, A.

1994-01-01

A procedure for preparation of liquid scintillation counting organic samples of the Di-2-ethylhexyl phosphate calcium complex and the 2-ethylhexanoate calcium salt, labelled with 45Ca, is described. The chemical quench, the counting stability and spectral evolution of both compounds is studied in six scintillators,Toluene-alcohol, Dioxane-naphtalene, Hi safe II, Ultimate-Gold and Instagel, and compared to results obtained from a commercial solution of 4 5CaCl2. (Author) 7 refs

Liquid scintillation counting standardization of 125I in organic and inorganic samples by the CIEMAT/NIST method; Calibracion por centelleo liquido del 125I en muestras inorganicas y organicas, mediante el metodo CIEMAT/NIST

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J. M.; Grau Carles, A.

1994-07-01

The liquid scintillation counting standardization of organic and inorganic samples of ''I25I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%. (Author) 14 refs.

A study of light collection efficiency in scintillation detectors

International Nuclear Information System (INIS)

Xiaoguang, Y.

1984-01-01

A group of computer programs was set up to study the light collection efficiency in scintillation detectors with rectangular cross sections. The input conditions can be chosen arbitrarily, including: the size, light attenuation length and refraction index of the scintillator and light guide, the refraction index of the coupling medium, the reflection characteristics of the walls, and the position of light sources. A few examples are discussed in this article. (orig.)

Liquid Scintillation High Resolution Spectral Analysis

Energy Technology Data Exchange (ETDEWEB)

Grau Carles, A.; Grau Malonda, A.

2010-08-06

The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

Liquid Scintillation High Resolution Spectral Analysis

International Nuclear Information System (INIS)

Grau Carles, A.; Grau Malonda, A.

2010-01-01

The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

Optimization of Plastic Scintillator Thicknesses for Online Beta Detection in Mixed Fields

Energy Technology Data Exchange (ETDEWEB)

Pourtangestani, K.; Machrafi, R. [University of Ontario Institute of Technology, Oshawa, ON (Canada)

2013-07-15

For efficient beta detection in a mixed beta-gamma field, Monte Carlo simulation models have been developed to optimize the thickness of a plastic scintillator used in whole body monitor. The simulation has been performed using MCNP/X code and different thicknesses of plastic scintillators ranging from 150 to 600 {mu}m have been used. The relationship between the thickness of the scintillator and the efficiency of the detector has been analysed. For 150 {mu}m thickness, an experimental investigation has been conducted with different beta sources at different positions on the scintillator and the counting efficiency of the unit has been measured. Evaluated data along with experimental ones have been discussed. A thickness of 300 {mu}m to 500 {mu}m has been found to be an optimum thickness for better beta detection efficiency in the presence of low energy gamma ray. (author)

Determination of 90Sr by liquid scintillation counting

International Nuclear Information System (INIS)

Cerchetti, Maria L.; Aghazarian, V.P.

2006-01-01

99m Tc, the result of the radioactive decay of 99 Mo, is one of the most applied radioisotopes in nuclear medicine and is used in nuclear medicine as a radiopharmaceutical product. It is important to ensure 99 Mo quality in order to fit the 99m Tc quality specifications. The main objective was to obtain a technique for 90 Sr determination in 99 Mo and environmental samples. The purification of 90 Sr is performed by extraction chromatography where crown-ether resin (Sr-Spec, Eichrom) was used. The measurement of the 90 Sr activity is performed by Liquid Scintillation Counting (LSC) using the double windows method. This method permits the 90 Sr determination without waiting until radiochemical equilibrium 90 Sr / 90 Y has been reached. The recovery factor was determined by gamma spectrometry with 85 Sr, and by gravimetry with stable strontium carrier solution. The minimum detectable activity was 0,05 Bq. The recovery factor was the major contribution in the total uncertainty. (author)

Comparison of analysis techniques by liquid scintillation and Cerenkov Effect for {sup 40}K quantification in aqueous samples; Comparacion de las tecnicas de analisis por centelleo liquido y efecto Cerenkov para la cuantificacion {sup 40}K en muestras acuosas

Energy Technology Data Exchange (ETDEWEB)

Miranda C, L.; Davila R, J. I.; Lopez del R, H.; Mireles G, F., E-mail: lilimica20@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

2015-09-15

In this work the counting by liquid scintillation and Cerenkov Effect to quantify {sup 40}K in aqueous samples was used. The performance of both techniques was studied by comparing the response of three commercial liquid scintillation OptiPhase HiSafe 3, Ultima Gold Ab and OptiPhase TriSafe, the vial type and presentation conditions of the sample for counting. In liquid scintillation, the ability to form homogeneous mixtures depended on the ionic strength of the aqueous solutions. The scintillator OptiPhase HiSafe 3 showed a greater charge capacity for solutions with high ionic strength (<3.4), while the scintillator OptiSafe TriSafe no form homogeneous mixtures for solutions of ionic strength higher than 0.3. Counting efficiencies for different proportions of sample and scintillator near 100% for the scintillators OptiSafe HiSafe 3 and Ultima Gold Ab were obtained. In the counting by Cerenkov Effect, the efficiency and sensitivity depended of the vial type; polyethylene vials were more suitable for counting that the glass vials. The sample volume had not significant effect on counting efficiency, obtaining an average value of 44.8% for polyethylene vials and 37.3% for glass vials. Therefore, the liquid scintillation was more efficient and sensitive for the measurement of {sup 40}K in aqueous solutions. (Author)

Alpha/beta separation in liquid scintillation gel samples

International Nuclear Information System (INIS)

Grau Carles, A.; Grau Malonda, A.

1994-01-01

The pulse shape analysis commonly used in liquid scintillation alpha/beta separations is satisfactory for moderate quench levels. However, for gel samples, the alpha particle counting efficiency is never greater than 10%, and an optimum separation of the alpha component cannot be achieved when beta to alpha counting rate ratios are greater than 100. In such cases, it is better to use a spectrum analysis method for alpha/beta separation. ((orig.))

Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches

International Nuclear Information System (INIS)

Danevich, F.A.; Kobychev, V.V.; Kobychev, R.V.; Kraus, H.; Mikhailik, V.B.; Mokina, V.M.; Solsky, I.M.

2014-01-01

Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO 4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreement

Gross alpha and gross beta determination in surface and groundwater water by liquid scintillation counting (LSC)

International Nuclear Information System (INIS)

Faria, Ligia S.; Moreira, Rubens M.

2013-01-01

The present study has used 40 samples of groundwater and surface water collected at four different sites along the period of one year in Brumadinho and Nova Lima, two municipalities in the State of Minas Gerais, Brazil, as part of a more extensive study aiming at determination of the natural radioactivity in the water used for domestic use. These two sites are inside an Environmental Protection Area is located in a region of very intensive iron ore exploration. In addition of mineral resources, the region has a geological characteristic that includes quartzitic conglomerates associated with uranium. Radioactivity levels were determined via liquid scintillation counting (LSC), a fast and high counting efficiency method that can be advantageously employed to determine gross alpha and gross beta activity in liquid samples. Previously to gross alpha and gross beta counting the samples were acidified with concentrated HNO 3 in the field. The technique involved a pre-concentration of the sample to obtain a low detection limit. Specific details of the employed methodology are commented. The results showed that concentrations of gross alpha natural activity and gross beta values ranged from less than the detection limit of the equipment (0.03 Bq.L -1 ) to 0.275 ± 0.05 Bq.L -1 for gross alpha. As regards gross beta, all samples were below the limit of detection. (author)

Measures to handle accidental contamination of persons with standard counting devices available in a department of nuclear medicine

International Nuclear Information System (INIS)

Aiginger, H.; Lauer, D.; Unfried, E.; Koenig, F.; Ogris, E.

1998-01-01

The assets and shortcomings of a well-type NaI detector and a Ge detector were examined using the Marinelli geometry, test tube geometry, and beaker geometry. Plots of the efficiency vs. energy (efficiency calibration), recorded time vs. true time (dead-time effects), and maximum activity vs. energy are reproduced. A high counting efficiency is typical of the scintillation detector in the well for the test tube geometry, particularly in the low energy range. For energies higher than 100 keV, the counting efficiency decreases because of the increasing penetration of the detector bulk by high-energy photons. For the germanium detector, the highest counting efficiency was achieved in the beaker geometry. A linear relationship exists between the calculated and measured counts at the beginning of the recorded curve for both systems. For the well-type detector the maximum detectable count rate was about 30 kcps, the linearity of the plot of the true count rate was guaranteed up to 10 kcps. Dead time correction was to be made at higher count rates. For the germanium detector the maximum detectable count rate was only about 8 kcps due to the longer dead time, the linear segment, however, was longer than for the scintillation detector. It is concluded that although the maximum detectable count rate of the germanium detector is lower, higher true activities can be detected with it owing to the lower detection efficiency. The well-type scintillation detector is advantageous for the test tube geometry. (P.A.)

Gross beta determination in drinking water using scintillating fiber array detector.

Science.gov (United States)

Lv, Wen-Hui; Yi, Hong-Chang; Liu, Tong-Qing; Zeng, Zhi; Li, Jun-Li; Zhang, Hui; Ma, Hao

2018-04-04

A scintillating fiber array detector for measuring gross beta counting is developed to monitor the real-time radioactivity in drinking water. The detector, placed in a stainless-steel tank, consists of 1096 scintillating fibers, both sides of which are connected to a photomultiplier tube. The detector parameters, including working voltage, background counting rate and stability, are tested, and the detection efficiency is calibrated using standard potassium chloride solution. Water samples are measured with the detector and the results are compared with those by evaporation method. The results show consistency with those by evaporation method. The background counting rate of the detector is 38.131 ± 0.005 cps, and the detection efficiency for β particles is 0.37 ± 0.01 cps/(Bq/l). The MDAC of this system can be less than 1.0 Bq/l for β particles in 120 min without pre-concentration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Measurement and simulation of neutron detection efficiency in lead-scintillating fiber calorimeters

Energy Technology Data Exchange (ETDEWEB)

Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati, INFN (Italy); Bini, C. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Roma (Italy); Curceanu, C. [Laboratori Nazionali di Frascati, INFN (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Ferrari, A. [Fondazione CNAO, Milano (Italy); Fiore, S.; Gauzzi, P. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Giovannella, S., E-mail: simona.giovannella@lnf.infn.i [Laboratori Nazionali di Frascati, INFN (Italy); Happacher, F. [Laboratori Nazionali di Frascati, INFN (Italy); Iliescu, M. [Laboratori Nazionali di Frascati, INFN (Italy); IFIN-HH, Bucharest (Romania); Martini, M. [Laboratori Nazionali di Frascati, INFN (Italy); Dipartimento di Energetica dell' Universita ' La Sapienza' , Roma (Italy); Miscetti, S. [Laboratori Nazionali di Frascati, INFN (Italy); Nguyen, F. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Passeri, A. [INFN Sezione di Roma Tre, Roma (Italy); Prokofiev, A. [Svedberg Laboratory, Uppsala University (Sweden); Sciascia, B. [Laboratori Nazionali di Frascati, INFN (Italy)

2009-12-15

The overall detection efficiency to neutrons of a small prototype of the KLOE lead-scintillating fiber calorimeter has been measured at the neutron beam facility of The Svedberg Laboratory, TSL, Uppsala, in the kinetic energy range [5-175] MeV. The measurement of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 30% to 50%. This value largely exceeds the estimated 8-15% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beam line has been performed with the FLUKA Monte Carlo code. First data-MC comparisons are encouraging and allow to disentangle a neutron halo component in the beam.

Measurement and simulation of neutron detection efficiency in lead-scintillating fiber calorimeters

International Nuclear Information System (INIS)

Anelli, M.; Bertolucci, S.; Bini, C.; Branchini, P.; Curceanu, C.; De Zorzi, G.; Di Domenico, A.; Di Micco, B.; Ferrari, A.; Fiore, S.; Gauzzi, P.; Giovannella, S.; Happacher, F.; Iliescu, M.; Martini, M.; Miscetti, S.; Nguyen, F.; Passeri, A.; Prokofiev, A.; Sciascia, B.

2009-01-01

The overall detection efficiency to neutrons of a small prototype of the KLOE lead-scintillating fiber calorimeter has been measured at the neutron beam facility of The Svedberg Laboratory, TSL, Uppsala, in the kinetic energy range [5-175] MeV. The measurement of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 30% to 50%. This value largely exceeds the estimated 8-15% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beam line has been performed with the FLUKA Monte Carlo code. First data-MC comparisons are encouraging and allow to disentangle a neutron halo component in the beam.

Variable sampling-time technique for improving count rate performance of scintillation detectors

International Nuclear Information System (INIS)

Tanaka, E.; Nohara, N.; Murayama, H.

1979-01-01

A new technique is presented to improve the count rate capability of a scintillation spectrometer or a position sensitive detector with minimum loss of resolution. The technique is based on the combination of pulse shortening and selective integration in which the integration period is not fixed but shortened by the arrival of the following pulse. Theoretical analysis of the degradation of the statiscal component of resolution is made for the proposed system with delay line pulse shortening, and the factor of resolution loss is formulated as a function of the input pulse rate. A new method is also presented for determining the statistical component of resolution separately from the non-statistical system resolution. Preliminary experiments with a NaI(Tl) detector have been carried out, the results of which are consistent with the theoretical prediction. However, due to the non-exponential scintillation decay of the NaI(Tl) crystal, a simple delay line clipping is not satisfactory, and an RC high-pass filter has been added, which results in further degradation of the statistical resolution. (Auth.)

Development of water radiocontamination monitor using a plastic scintillator detector

International Nuclear Information System (INIS)

Mesquita, C.H. de; Madi Filho, T.; Hamada, M.M.

1990-01-01

An alpha, beta and gamma radiation water monitor was developed using a plastic scintillator detector with a sensitivity level of 15 bplastic scintillator detector with a sensitivity level of 15 Bq.L -1 and a counting efficiency of 25% for 131 I. It was proposed to be used in the radiation monitoring program of the research reactor swimming-pool of Sao Paulo. A simplified design and some properties of this monitor are presented. (author) [pt

Three L-subshells atomic model to compute counting efficiency of electron-capture nuclides; Modelo con tres subcapas L para calcular la eficiencia de recuento de nucleidos que se desintegran por captura electronica

Energy Technology Data Exchange (ETDEWEB)

Grau, A.; Arcos, J. M. los

1986-07-01

The present paper develops a three L-subshell a and K, M-a hells atomic model in order to obtain the counting efficiency in liquid scintillation counting. Mathematical expressions are given to calculate the probabilities of 264 different atomic rearrangement way so as the corresponding effective energies. This new model will permit to test the influence of the different atomic and nuclear parameters upon the counting efficiency nuclides of low and medium atomic number decaying by electron capture. (Author) 8 refs.

Age determination of trace plutonium using liquid scintillation counting and α-spectrometry

International Nuclear Information System (INIS)

Chen Yan; Chang Zhiyuan; Zhao Yonggang; Li Jinghuai; Shu Fujun

2010-01-01

Liquid scintillation counting combined with α-spectrometry through measuring 241 Pu/ 241 Am ratio to determine the age of trace Pu was studied. The technique was explored for the age determination of nanogram grade Pu sample on the basis of Pu/Am separation. The ages of two Pu samples-one with known and the other with unknown age were determined by the method. The determined age by the method is in agreement with the reference value. The established method for determining the age of trace Pu can be adopted in the verification activities of nuclear safeguards and nuclear arms control. (authors)

Preparation and calibration by liquid scintillation of a sample of Cl 36

International Nuclear Information System (INIS)

Grau Malonda, A.; Los Arcos, J.M.; Rodriguez Barquero, L.; Suarez, C.

1989-01-01

A procedure to prepare a sample of Clorine 36, as Li 36 Cl, able to be measured by liquid scintillation counting, is described. The sample is chemically stable, with no variation of the quenching parameter up to 4 mg of LiCl per 15 ml of scintillator, keeps constant the counting efficiency for concentration higher than 40 μg of Li 36 Cl in that volume, and shows no deterioration over a 3 weed period. The Li 36 Cl solution has been standarized using the free parameter method with different volumes of toluene, PCS and Instagel, to an uncertainty of 0,3% (Author)

Testing the count rate performance of the scintillation camera by exponential attenuation: Decaying source; Multiple filters

International Nuclear Information System (INIS)

Adams, R.; Mena, I.

1988-01-01

An algorithm and two fortrAN programs have been developed to evaluate the count rate performance of scintillation cameras from count rates reduced exponentially, either by a decaying source or by filtration. The first method is used with short-lived radionuclides such as 191 /sup m/Ir or 191 /sup m/Au. The second implements a National Electrical Manufacturers' Association (NEMA) protocol in which the count rate from a source of 191 /sup m/Tc is attenuated by a varying number of copper filters stacked over it. The count rate at each data point is corrected for deadtime loss after assigning an arbitrary deadtime (tau). A second-order polynomial equation is fitted to the logarithms of net count rate values: ln(R) = A+BT+CT 2 where R is the net corrected count rate (cps), and T is the elapsed time (or the filter thickness in the NEMA method). Depending on C, tau is incremented or decremented iteratively, and the count rate corrections and curve fittings are repeated until C approaches zero, indicating a correct value of the deadtime (tau). The program then plots the measured count rate versus the corrected count rate values

Studying, Determining The Radionuclide Of Tritum In The Water Samples (Rain, Surface Water) By Using Liquid Scintillation Counting (TRi-carb 3180TR/SL)

International Nuclear Information System (INIS)

Nguyen Thi Linh; Nguyen Dinh Tung; Truong Y; Le Nhu Sieu; Nguyen Van Phuc; Nguyen Van Phu; Nguyen Kim Thanh

2014-01-01

Tritium in the environment is of natural or man-made origin. Tritium is a radioactive isotope that occurs in the environment and is associated with the interaction of cosmic ray in the atmosphere. However, the most significant sources of tritium in the environment results from nuclear weapons testing in the atmosphere carried out during the late 1950s and early 1960s. Today, the most important new sources of tritium in the environments, such as power stations, processing and using of isotopes released the local tritium. The objective of this study is the application of the liquid scintillation technique to tritium analysis in water samples (rain, and surface waters). Following the Eichrom Tritium Column technique, an aliquot of the passed tritium resin sample (10 mL) is mixed with 10 mL of scintillation cocktail (Ultima Gold LLT, Packard) in 20-mL plastic- container vials and the sample activity is determined using a liquid scintillation spectrometer, Tri-carb 3180TR/SL. Counting efficiency is evaluated with internal standards. The tritium concentrations of water samples that were collected from DaLat, Lamdong range between 0 to 36.2 TU. (author)

Optics study of liquid scintillation counting systems; Estudio de la Optica en sistemas de medida por centelle liquido

Energy Technology Data Exchange (ETDEWEB)

Duran Ramiro, M. T.; Garcia-Torano, E.

2005-07-01

Optics is a key issue in the development of any liquid scintillation counting (LSC) system. Light emission in the scintillating solution, transmission through the vial and reflector design are some aspects that need to be considered in detail. This paper describes measurements and calculations carried out to optimise these factors for the design of a new family of LSC counters. Measurements of the light distribution emitted by a scintillation vial were done by autoradiographs of cylindrical vials made of various materials and results were compared to those obtained by direct measurements of the light distribution made by scanning the vial with a photomultiplier tube. Calculations were also carried out to study the light transmission in the vial and the optimal design of the reflector for a system with one photomultiplier tube. (Author)

Preparation of 45 Ca (HDEHP)n and (C8H15O2)2 samples for liquid scintillation counting, compared to 45CaCl2 results

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Los Arcos Merino, J.M.; Grau Malonda, A.

1994-01-01

A procedure for preparation of liquid scintillation counting organic samples of the Di-2-ethylhexyl phosphate calcium complex and the 2-ethyhexanoate calcium salt, labelled with ''45 Ca, is described. The chemical quench, the counting stability and spectral evolution of both compounds is studied in six scintillators, Toluene, Toluene-alcohol, Dioxane-napthalhene, Hisafe II, Ultima-Gold and Instagel, and compared to results obtained from a commercial solution of ''45 CaCl 2

Measurement and simulation of the neutron detection efficiency with a Pb-scintillating fiber calorimeter

Energy Technology Data Exchange (ETDEWEB)

Anelli, M; Bertolucci, S; Curceanu, C; Giovannella, S; Happacher, F; Iliescu, M; Martini, M; Miscetti, S [Laboratori Nazionali di Frascati, INFN (Italy); Battistoni, G [Sezione INFN di Milano (Italy); Bini, C; Zorzi, G De; Domenico, Adi; Gauzzi, P [Ubiversita degli Studi ' La Sapienza' e Sezine INFN di Roma (Italy); Branchini, P; Micco, B Di; Ngugen, F; Paseri, A [Universita degli di Studi ' Roma Tre' e Sezione INFN di Roma Tre (Italy); Ferrari, A [Fondazione CNAO, Milano (Italy); Prokfiev, A [Svedberg Laboratory, Uppsala University (Sweden); Fiore, S, E-mail: matteo.martino@inf.infn.i

2009-04-01

We have measured the overall detection efficiency of a small prototype of the KLOE PB-scintillation fiber calorimeter to neutrons with kinetic energy range [5,175] MeV. The measurement has been done in a dedicated test beam in the neutron beam facility of the Svedberg Laboratory, TSL Uppsala. The measurements of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 28% to 33%. This value largely exceeds the estimated {approx}8% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beam line has been performed with the FLUKA Monte Carlo code. The simulated response of the detector to neutrons is presented together with the first data to Monte Carlo comparison. The results show an overall neutron efficiency of about 35%. The reasons for such an efficiency enhancement, in comparison with the typical scintillator-based neutron counters, are explained, opening the road to a novel neutron detector.

Apparent and actual 14C retention in the slower turnover bicarbonate pool in man when using liquid scintillation counting

International Nuclear Information System (INIS)

Clague, M.B.; Keir, M.J.; Clayton, C.B.

1979-01-01

The use of liquid scintillation counting to determine 14 CO 2 expiration without correct calibration of the apparatus suggests that about 25% of the label is retained within the slower turnover bicarbonate pool. Calibration reduces this figure to 13% and is in agreement with the figure obtained using a calibrated ionisation chamber. The discrepancy is due to reduction in the specific radioactivity in the vial, the mechanism involved being unknown, but it may be a characteristic of certain liquid scintillators under certain conditions. (author)

Performance of two liquids scintillation and optimization of a Wallac 1411 counter in the tritium quantification in aqueous samples

International Nuclear Information System (INIS)

Contreras de la Cruz, E. de J.; Lopez del Rio, H.; Davila R, J. I.; Mireles G, F.; Pinedo V, J. L.

2014-10-01

The optimization of a liquid scintillation counting Wallac 1411 is presented as well as the performance of the liquids scintillation miscible in water OptiPhase Hi Safe 3 and Last Gold Ab, in the tritium quantification in aqueous samples. The luminescence effect, the quenching, the solution ph and the level of pulse amplitude comparator (Pac) were evaluated in the response of both liquids scintillation in the tritium measurement. The quenching and the luminescence modify the scintillators response; in the first of them the counting efficiency decreases and the minimum detectable activity increases; the second interferes in the tritium quantification in the interest window, but the effect disappears after 4 hours of darkness of the samples. The maximum counting efficiency was of 24% for OptiPhase Hi Safe 3 and 31% for Last Gold Ab, diminishing with the quenching until values of 8 and 11%, respectively. For a counting time of 6 hours and lower quenching, the minimum detectable concentration for OptiPhase Hi Safe 3 was of 13.4 ± 0.2 Bq/L and 9.9 ± 0.1 Bq/L for Last Gold Ab. Both scintillators responded appropriately to sour and basic solutions, being only presented chemiluminescence in Last Gold Ab to ph highly basic. The Pac application that varies between 1 and 256 does not have effect in the tritium measurement until values above 90. (Author)

A methodology for the optimization of the estimation of tritium in urine by liquid scintillation counting

International Nuclear Information System (INIS)

Joseph, S.; Kramer, G.H.

1982-10-01

A method has been designed to optimize liquid scintillation (LS) urinalysis with respect to sensitivity and cost. Three related factors, quench, sample composition and counting efficiency, were measured simultaneously and the results plotted in three dimensions to determine the optimum conditions for urinalysis. Picric acid was used to simulate quenching. Subsequent urinalysis experiments showed that quenching by picric acid was analogous to urine quenching. The optimization methodology was applied to ten commercial LS cocktails and a wide divergence in results was obtained. This method can also be used to optimize minimum detectable activities (MDA) but the results show that there is no fixed sample composition that can be used for all the various types of urine samples; however, it is possible to achieve general improvements of at least a factor of 2 in the MDA for Scintiverse (the only one tested for this particular application of the methodology)

Advantages of GSO Scintillator in Imaging and Law Level Gamma-ray Spectroscopy

CERN Document Server

Sharaf, J

2002-01-01

The single GSO crystal is an excellent scintillation material featuring a high light yield and short decay time for gamma-ray detection. Its performance characteristics were investigated and directly compared to those of BGO. For this purpose, the two scintillators are cut into small crystals of approximately 4*4*10 mm sup 3 and mounted on a PMT. Energy resolution, detection efficiency and counting precision have been measured for various photon energies. In addition to this spectroscopic characterization, the imaging performance of GSO was studied using a scanning rig. The modulation transfer function was calculated and the spatial resolution evaluated by measurements of the detector's point spread function. It is shown that there exists some source intensity for which the two scintillators yield identical precision for identical count time. Below this intensity, the GSO is superior to the BGO detector. The presented properties of GSO suggest potential applications of this scintillator in gamma-ray spectrosc...

Study on calibration of neutron efficiency and relative photo-yield of plastic scintillator

International Nuclear Information System (INIS)

Peng Taiping; Zhang Chuanfei; Li Rurong; Zhang Jianhua; Luo Xiaobing; Xia Yijun; Yang Zhihua

2002-01-01

A method used for the calibration of neutron efficiency and the relative photo yield of plastic scintillator is studied. T(p, n) and D(d, n) reactions are used as neutron resources. The neutron efficiencies and the relative photo yields of plastic scintillators 1421 (40 mm in diameter and 5 mm in thickness) and determined in the neutron energy range of 0.655-5 MeV

Calculation of the detection efficiency in liquid scintillators. II. Single positron emitters; Calculo de la eficiencia de deteccion en liquidos centelleadores. II Nucleidos que se desintegran por emision simple de positrones

Energy Technology Data Exchange (ETDEWEB)

Grau Malonda, A.; Garcia Torano, E.

1982-07-01

Counting efficiency as a function of the figure of merit for 30 positron emitters has been computed from the positron energy spectrum. Only the efficiency contribution of positrons has been taken into consideration. The contribution of the annihilation photons depending on the volume of the scintillator will be investigated in a near future. Efficiency vs figure of merit is plotted and tabulated. (Author) 19 refs.

Measurement of the neutron detection efficiency of a 80% absorber-20% scintillating fibers calorimeter

Energy Technology Data Exchange (ETDEWEB)

Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); Bini, C., E-mail: cesare.bini@roma1.infn.i [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Via della Vasca Navale, 84 I-00146 Roma (Italy); Corradi, G.; Curceanu, C. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Via della Vasca Navale, 84 I-00146 Roma (Italy); INFN Sezione di Roma Tre, Via della Vasca Navale, 84 I-00146 Roma (Italy); Ferrari, A. [Institute of Safety Research and Institute of Radiation Physics, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden (Germany); Fiore, S. [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Gauzzi, P., E-mail: paolo.gauzzi@roma1.infn.i [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Giovannella, S.; Happacher, F. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); Iliescu, M. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); ' Horia Hulubei' National Institute of Physics and Nuclear Engineering, Str. Atomistilor no. 407, P.O. Box MG-6 Bucharest-Magurele (Romania); Luca, A.; Martini, M.; Miscetti, S. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy)

2011-01-21

The neutron detection efficiency of a sampling calorimeter made of 1 mm diameter scintillating fibers embedded in a lead/bismuth structure has been measured at the neutron beam of The Svedberg Laboratory at Uppsala. A significant enhancement of the detection efficiency with respect to a bulk organic scintillator detector with the same thickness is observed.

An improved method for 85Kr analysis by liquid scintillation counting and its application to atmospheric 85Kr determination

International Nuclear Information System (INIS)

Momoshima, Noriyuki; Inoue, Fumio; Sugihara, Shinji; Shimada, Jun; Taniguchi, Makoto

2010-01-01

Atmospheric 85 Kr concentration at Fukuoka, Japan was determined by an improved 85 Kr analytical method using liquid scintillation counting (LSC). An average value of 1.54 ± 0.05 Bq m -3 was observed in 2008, which is about two times that measured in 1981 at Fukuoka, indicating a 29 mBq y -1 rate of increase as an average for these 27 years. The analytical method developed involves collecting Kr from air using activated charcoal at liquid N 2 temperature and purifying it using He at dry ice temperature, followed by Kr separation by gas chromatography. An overall Kr recovery of 76.4 ± 8.1% was achieved when Kr was analyzed in 500-1000 l of air. The Kr isolated by gas chromatography was collected on silica gel in a quartz glass vial cooled to liquid N 2 temperature and the activity of 85 Kr was measured with a low-background LS counter. The detection limit of 85 Kr activity by the present analytical method is 0.0015 Bq at a 95% confidence level, including all propagation errors, which is equivalent with 85 Kr in 1.3 l of the present air under the analytical conditions of 72.1% counting efficiency, 0.1597 cps background count rate, and 76.4% Kr recovery.

Color quench correction for low level Cherenkov counting.

Science.gov (United States)

Tsroya, S; Pelled, O; German, U; Marco, R; Katorza, E; Alfassi, Z B

2009-05-01

The Cherenkov counting efficiency varies strongly with color quenching, thus correction curves must be used to obtain correct results. The external (152)Eu source of a Quantulus 1220 liquid scintillation counting (LSC) system was used to obtain a quench indicative parameter based on spectra area ratio. A color quench correction curve for aqueous samples containing (90)Sr/(90)Y was prepared. The main advantage of this method over the common spectra indicators is its usefulness also for low level Cherenkov counting.

Scintillating fiber tracking at high luminosities using Visible Light Photon counter readout

International Nuclear Information System (INIS)

Atac, M.

1995-11-01

This paper reviews the research work on the Visible Light Photon Counters (VLPC) that have been developed for the scintillating fiber tracking at high luminosity colliders and high rate fixed target experiments. The devices originated from the joint work between UCLA and Rockwell International Science Center. The VLPCs are capable of counting photons very efficiently down to a single photon level with high avalanche gain, producing pulses at very high rates with very short rise times. Due to small gain dispersions they can be used in counting photons with high quantum efficiencies, therefore they are excellent devices for charged particle tracking using small diameter scintillating plastic fibers. In this paper, fiber tracking for the CDF and D0 upgrades and a possible usage of the VLPC readout for the experiment E803 at Fermilab will be discussed

Evaluation of the Detection Efficiency of LYSO Scintillator in the Fiber-Optic Radiation Sensor

Directory of Open Access Journals (Sweden)

Chan Hee Park

2014-01-01

Full Text Available The aim of this study was to develop and evaluate fiber-optic sensors for the remote detection of gamma rays in areas that are difficult to access, such as a spent fuel pool. The fiber-optic sensor consists of a light-generating probe, such as scintillators for radiation detection, plastic optical fibers, and light-measuring devices, such as PMT. The (Lu,Y2SiO5:Ce(LYSO:Ce scintillator was chosen as the light-generating probe. The (Lu,Y2SiO5:Ce(LYSO:Ce scintillator has higher scintillation efficiency than the others and transmits light well through an optical fiber because its refraction index is similar to the refractive index of the optical fiber. The fiber-optic radiation sensor using the (Lu,Y2SiO5:Ce(LYSO:Ce scintillator was evaluated in terms of the detection efficiency and reproducibility for examining its applicability as a radiation sensor.

Estimating the standard deviation for 222Rn scintillation counting - a note concerning the paper by Sarmiento et al

International Nuclear Information System (INIS)

Key, R.M.

1977-01-01

In a recent report Sarmiento et al.(1976) presented a method for estimating the statistical error associated with 222 Rn scintillation counting. Because of certain approximations, the method is less accurate than that of an earlier work by Lucas and Woodward (1964). The Sarmiento method and the Lucas method are compared, and the magnitude of errors incurred using the approximations are determined. For counting times greater than 300 minutes, the disadvantage of the slight inaccuracies of the Sarmiento method are outweighed by the advantage of easier calculation. (Auth.)

Isolation and activity determination of 99Tc in nuclear waste by liquid scintillation counting

International Nuclear Information System (INIS)

Reis Junior, Aluisio S.; Temba, Eliane S.C.; Kastner, Geraldo F.; Monteiro, Roberto P.G.

2011-01-01

A radiochemical separation and purification for technetium was proposed for radioactive waste in which rhenium is to be used as a yield monitor. The separation was performed by anion exchange chromatography and the purification was performed by extraction chromatography using a TEVA resin.The determination of 99 Tc was by liquid scintillation counting and rhenium was activated by Triga Mark 1 research reactor and measured by gamma spectrometry. Some real samples of nuclear waste such as evaporator concentrate and filter were analysed. The chemical recovery determined using rhenium as tracer was around 90 %. (author)

High Efficiency, Low Cost Scintillators for PET

International Nuclear Information System (INIS)

Kanai Shah

2007-01-01

Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized

Comparison of two types of scintillation probe for moisture density gauge

International Nuclear Information System (INIS)

Machaj, B.

1974-01-01

Investigations of pulse shape discrimination scintillation probe, and amplitude discrimination probe as a detector for moisutre density gauge have been carried out. It was found that sandwich scintillator consisting of NE-421 + NE-102A was the best for pulse shape discrimination probe for thermal neutrons and gamma radiation detection. Similarly LiJ(Eu) crystal was the best for amplitude discrimination probe. The amplitude discrimination probe with LiJ(Eu) comparing to pulse shape discrimination probe with sandwich scintillator, provides approximately two times higher thermal neutron detection efficiency and higher count rate stability. It is considered therefore more suitable as the detector for moisture density gauge. (author)

Sample oxidation for liquid scintillation counting

International Nuclear Information System (INIS)

Kisieleski, W.E.; Buess, E.M.

1976-01-01

The general features of biological and medical investigations which are responsible for the demands such investigations place upon the design specifications of liquid scintillation counters and associated methodology are reviewed. Special emphasis is given to the oxidative technique for sample preparation

Paraffin scintillator for radioassay of solid support samples

International Nuclear Information System (INIS)

Fujii, Haruo; Takiue, Makoto

1989-01-01

A new paraffin scintillator used for solid support sample counting has been proposed, and its composition and various characteristics are described. The solid support sample treated with this scintillator can be easily handled because of rigid sample conditions. This technique provides great advantages such as the elimination of a large volume of scintillator and little radioactive waste material by using an economical polyethylene bag instead of the conventional counting vial. (author)

Use of liquid scintillation counting for quantitative analysis of volatile organic compounds in batch isotherm analysis

International Nuclear Information System (INIS)

Wickman, D.C.

1987-01-01

An estimate of how rapidly hazardous wastes move through subsurface soils via ground water is important to predict the location and concentration of the contaminant plume vs. time. The contaminated ground water system may be viewed as an HPLC column with the organic components of the waste in adsorption/desorption equilibrium with the subsurface soil. The batch isotherm method was chosen to determine the equilibrium constant between trichloroethylene, o-dichlorobenzene, 1-methyl naphthalene and aquifer materials obtained from various locations around the country. Liquid Scintillation counting has been found to be an excellent technique for batch isotherm analysis; using 14C labeled compounds, it affords unattended analysis, accuracy at very low concentrations and rapid data reduction. Ten ml serum containing about 5 ml water and a known weight of soil (approximately 2 grams) were spiked with the labeled solution to yield organic solute concentrations in the range of 0.02-1.0 mg/1. Six different concentrations were used. After spiking, the bottles were filled to the top with water and crimp sealed with teflon coated septa. All soil containing bottles were then rotated at 50 rpm and 22 degrees Celsius. Twenty-four hours later the bottles were uncapped and a 1.4 ml aliquot was removed and placed in scintillation cocktail and counted

Analytical calculations of the efficiency of gamma scintillators total efficiency for coaxial disk sources

Energy Technology Data Exchange (ETDEWEB)

Selim, Y S; Abbas, M I; Fawzy, M A [Physics Department, Faculty of Science, Alexandria University, Aleaxndria (Egypt)

1997-12-31

Total efficiency of clad right circular cylindrical Nal(TI) scintillation detector from a coaxial isotropic radiating circular disk source has been calculated by the of rigid mathematical expressions. Results were tabulated for various gamma energies. 2 figs., 5 tabs.

Precise method for correcting count-rate losses in scintillation cameras

International Nuclear Information System (INIS)

Madsen, M.T.; Nickles, R.J.

1986-01-01

Quantitative studies performed with scintillation detectors often require corrections for lost data because of the finite resolving time of the detector. Methods that monitor losses by means of a reference source or pulser have unacceptably large statistical fluctuations associated with their correction factors. Analytic methods that model the detector as a paralyzable system require an accurate estimate of the system resolving time. Because the apparent resolving time depends on many variables, including the window setting, source distribution, and the amount of scattering material, significant errors can be introduced by relying on a resolving time obtained from phantom measurements. These problems can be overcome by curve-fitting the data from a reference source to a paralyzable model in which the true total count rate in the selected window is estimated from the observed total rate. The resolving time becomes a free parameter in this method which is optimized to provide the best fit to the observed reference data. The fitted curve has the inherent accuracy of the reference source method with the precision associated with the observed total image count rate. Correction factors can be simply calculated from the ratio of the true reference source rate and the fitted curve. As a result, the statistical uncertainty of the data corrected by this method is not significantly increased

Phoswich Detector for Simultaneous Counting of Alpha- and Beta-ray in a Pipe during Decommissioning

International Nuclear Information System (INIS)

Seo, B.K.; Kim, G.H.; Woo, Z.H.; Jung, Y.H.; Oh, W.Z.; Lee, K.W.; Han, M.J.

2006-01-01

A great quantity of waste has been generated during the decommissioning of nuclear facilities. These wastes are contaminated with various types of alpha, beta, and gamma nuclides. The contamination level of the decommissioning wastes must be surveyed for free release, but it is very difficult to monitor the radioactive contamination level of the pipe inside using conventional counting methods because of the small diameter. In this study a Phoswich detector for simultaneous counting of alpha- and beta-rays in a pipe was developed. The Phoswich detector is convenient for monitoring of alpha and beta contamination using only a single detector, which was composed of thin cylindrical ZnS(Ag) and plastic scintillator. The scintillator for counting an alpha particle has been applied a cylindrical polymer composite sheet, having a double layer structure of an inorganic scintillator ZnS(Ag) layer adhered onto a polymer sub-layer. The sub-layer in an alpha particle counting sheet is made of polysulfone, working as a mechanical and optical support. The ZnS(Ag) layer is formed by coating a ternary mixture of ZnS(Ag), cyano resin as a binder and solvent onto the top of a sub-layer via the screen printing method. The other layer for counting a beta particle used a commercially available plastic scintillator. The plastic scintillator was simulated by using the Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. Characteristics of the detector fabricated were also estimated. As a result, it was confirmed that detector capability was suitable for counting the beta ray. The overall counting results reveal that the developed Phoswich detector is efficient for simultaneous counting of alpha and beta ray in a pipe. (authors)

New scintillating crystals for PET scanners

CERN Document Server

Lecoq, P

2002-01-01

Systematic R&D on basic mechanism in inorganic scintillators, initiated by the Crystal Clear Collaboration at CERN 10 years ago, has contributed not to a small amount, to the development of new materials for a new generation of medical imaging devices with increased resolution and sensitivity. The first important requirement for a scintillator to be used in medical imaging devices is the stopping power for the given energy range of X and gamma rays to be considered, and more precisely the conversion efficiency. A high light yield is also mandatory to improve the energy resolution, which is essentially limited by the photostatistics and the electronic noise at these energies. A short scintillation decay time allows to reduce the dead time and therefore to increase the limiting counting rate. When all these requirements are fulfilled the sensitivity and image contrast are increased for a given patient dose, or the dose can be reduced. Examples of new materials under development by the Crystal Clear Collabor...

Discriminator setting and cocktail preparation for analysis of alpha and beta emitters in aqueous solution using liquid scintillation counter

International Nuclear Information System (INIS)

Zaini Hamzah; Masitah Alias; Zaharudin Ahmad

2011-01-01

Liquid scintillation counting (LSC) is not only being used to measure pure beta emitters, but it can be used to measure both alpha and beta emitters simultaneously. Measurement of alpha and beta emitters in aqueous solution is done using a single sample. For the sample preparation, colorless detergent or emulsifier was used to incorporate the water into an organic based scintillator to produce a clear homogeneous solution, since this is the best form to give the highest count rate and detection efficiency. The instrument also need some attention, where after calibration, the LSC was set for the discriminator level which is suitable for measurement of both alpha and beta radiations. In this study, the focus is on the development of the best scintillation cocktail and establishes the best discriminator setting. From this study the best proportion of scintillation cocktail is 2:4:4 for water, toluene, and Triton-N101 (emulsifier) respectively and the best discriminator setting for alpha and beta counting are 120. (author)

Technology update on fast plastic scintillators for medical applications

International Nuclear Information System (INIS)

Lyons, P.B.

1977-01-01

Plastic scintillators appear to have potential utility in three research areas related to nuclear medicine: (1) high count rate applications in general, (2) positron camera applications, and (3) positron source localization through measurement of relative arrival times of annihilation quanta at two co-linear detectors. These three areas of applicability depend on improvement in three specific areas of plastic scintillator technology: (a) development of plastics with very fast decay times, (b) development of plastics with greatly improved high energy photon detection efficiencies (high-Z loaded plastics), and (c) improvement of fast timing system capabilities. The three preceding areas of improvement are discussed

Preparation and standardization of a sample of P 32 by liquid scintillation

International Nuclear Information System (INIS)

Rodriguez, L.; Grau, A.; Los Arcos, J.M.; Suarez, C.

1988-01-01

A procedure to standardize P 32 in liquid scintillation counting by labelling a tsributyl phosphate organic molecule is described. This method shows a high counting efficiency, over 99%, while keeping a good stability of samples in PCS or toluene, which vary less that 1% in two weed periods. The global uncertainty that results for calibrating the radioactive solution through this method has been less that 2.2%. (Author)

A Monte Carlo Model for Neutron Coincidence Counting with Fast Organic Liquid Scintillation Detectors

International Nuclear Information System (INIS)

Gamage, Kelum A.A.; Joyce, Malcolm J.; Cave, Frank D.

2013-06-01

Neutron coincidence counting is an established, nondestructive method for the qualitative and quantitative analysis of nuclear materials. Several even-numbered nuclei of the actinide isotopes, and especially even-numbered plutonium isotopes, undergo spontaneous fission, resulting in the emission of neutrons which are correlated in time. The characteristics of this i.e. the multiplicity can be used to identify each isotope in question. Similarly, the corresponding characteristics of isotopes that are susceptible to stimulated fission are somewhat isotope-related, and also dependent on the energy of the incident neutron that stimulates the fission event, and this can hence be used to identify and quantify isotopes also. Most of the neutron coincidence counters currently used are based on 3 He gas tubes. In the 3 He-filled gas proportional-counter, the (n, p) reaction is largely responsible for the detection of slow neutrons and hence neutrons have to be slowed down to thermal energies. As a result, moderator and shielding materials are essential components of many systems designed to assess quantities of fissile materials. The use of a moderator, however, extends the die-away time of the detector necessitating a larger coincidence window and, further, 3 He is now in short supply and expensive. In this paper, a simulation based on the Monte Carlo method is described which has been performed using MCNPX 2.6.0, to model the geometry of a sector-shaped liquid scintillation detector in response to coincident neutron events. The detection of neutrons from a mixed-oxide (MOX) fuel pellet using an organic liquid scintillator has been simulated for different thicknesses of scintillators. In this new neutron detector, a layer of lead has been used to reduce the gamma-ray fluence reaching the scintillator. The effect of lead for neutron detection has also been estimated by considering different thicknesses of lead layers. (authors)

Rapid determination of 226Ra in drinking water samples using dispersive liquid-liquid microextraction coupled with liquid scintillation counting

International Nuclear Information System (INIS)

Sadi, B.K.; Chunsheng Li; Kramer, G.H.; Johnson, C.L.; Queenie Ko; Lai, E.P.C.

2011-01-01

A new radioanalytical method was developed for rapid determination of 226 Ra in drinking water samples. The method is based on extraction and preconcentration of 226 Ra from a water sample to an organic solvent using a dispersive liquid-liquid microextraction (DLLME) technique followed by radiometric measurement using liquid scintillation counting. In DLLME for 226 Ra, a mixture of an organic extractant (toluene doped with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone) and a disperser solvent (acetonitrile) is rapidly injected into the water sample resulting in the formation of an emulsion. Within the emulsion, 226 Ra reacts with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone and partitions into the fine droplets of toluene. The water/toluene phases were separated by addition of acetonitrile as a de-emulsifier solvent. The toluene phase containing 226 Ra was then measured by liquid scintillation counting. Several parameters were studied to optimize the extraction efficiency of 226 Ra, including water immiscible organic solvent, disperser and de-emulsifier solvent type and their volume, chelating ligands for 226 Ra and their concentrations, inorganic salt additive and its concentration, and equilibrium pH. With the optimized DLLME conditions, the accuracy (expressed as relative bias, B r ) and method repeatability (expressed as relative precision, S B ) were determined by spiking 226 Ra at the maximum acceptable concentration level (0.5 Bq L -1 ) according to the Guidelines for Canadian Drinking Water Quality. Accuracy and repeatability were found to be less than -5% (B r ) and less than 6% (S B ), respectively, for both tap water and bottled natural spring water samples. The minimum detectable activity and sample turnaround time for determination of 226 Ra was 33 mBq L -1 and less than 3 h, respectively. The DLLME technique is selective for extraction of 226 Ra from its decay progenies. (author)

Method and apparstus for determining random coincidence count rate in a scintillation counter utilizing the coincidence technique

International Nuclear Information System (INIS)

Horrocks, D.L.

1980-01-01

A method and apparatus for the reliable determination of a random coincidence count attributable to chance coincidences of single-photon events which are each detected in only a single detector of a scintillation counter utilizing two detectors in a coincidence counting technique are described. A firstdelay device is employed to delay output pulses from one detector, and then the delayed signal is compared with the undelayed signal from the other detector in a coincidence circuit, to obtain an approximate random coincidence count. The output of the coincidence circuit is applied to an anti-coincidence circuit, where it is corrected by elimination of pulses coincident with, and attributable to, conventionally detected real coincidences, and by elimination of pulses coincident with, and attributable to, real coincidences that have been delayed by a second delay device having the same time parameter as the first. 8 claims

Performance of 2000CA/LL and 2260XL liquid scintillation spectrometers for low-level tritium and carbon-14 analyses

International Nuclear Information System (INIS)

Rozanski, K.; Stichler, W.; Schwarz, P.

1991-01-01

The performance of two commercially available liquid scintillation spectrometers for low-level counting of 3 H and 14 C has been investigated. Two models of new technology Tri-Carb spectrometers from the Packard Instrument Company were tested: the 2000CA/LL and 2260XL. The measurements revealed a superior 3 H performance of the 2000CA/LL equipment owing to its substantially higher counting efficiency. Results for 14 C are less conclusive and depend on the configuration of the counting parameters selected. A comparison of three commercially available scintillation cocktails for tritium assay in water samples revealed a superior performance for PicoFluor LLT. (Author)

The study of vial and cocktail for tritium radioactivity analysis of rain water by liquid scintillation counter

International Nuclear Information System (INIS)

Noh, Sung Jin; Kim, Hyo Jin; Kim, Hyun; Lee, Man Woo; Jeong, Dong Hyeok; Yang, Kwang Mo; Kang, Yeong Rok; Nam, Sang Hee

2015-01-01

Even though the current method for tritium (3H) analysis is routine, for the case of the low level of tritium in the environment, special conditions have to be fulfilled in order to obtain accurate and reliable tritium measurements. There are very little comparative data concerning commercial scintillating cocktails. The best cocktails for measuring tritium are those based on benzene derived solvent, and the worse cocktails are those which have complex chemical composition or contain too small concentration of scintillators. The aim of study was to investigate various vials and cocktails by comparison with the combination of few different scintillation cocktails and vials in our routine measurements according to count, efficiency, and the figure of merit (FOM). The comparison of three types of vials with scintillation cocktails for tritium activity analysis of rain water shows that glass vials have higher count rates and HiSafe 3 cocktails have lower FOM

Strontium-90 (90Sr) determination using liquid scintillation counting

International Nuclear Information System (INIS)

Cheberle, L.T.V.; Rosa, M.M.L.; Ferreira, M.T.; Taddei, M.H.T.

2015-01-01

This procedure describes a method for separation and measurement of strontium 90 Sr in water, soils, and biological samples. Water samples may be concentrated using evaporation or calcium phosphate coprecipitation. Soils and biological materials must be dissolved using wet digestion. Tracers and carriers must be added before the attack. Radioactive strontium is separated employing a specific resin before determination by liquid scintillation counting using the double energetic window method. The resin is used to concentrate strontium from samples. Stable strontium is used to monitor method yields and correct results to improve precision and accuracy. The presence of elemental strontium in the sample may bias the gravimetric yield determination. If it is suspected that natural strontium is present in the sample, its concentration should be determined by a suitable means (ICP), and the yield calculation properly modified. Sr-Spec resin with an 8M HNO 3 load solution is used to effectively remove 140 Ba and 40 K isotopes, as well as other interferences from the matrix. Tetravalent plutonium, neptunium, cerium and ruthenium, however, are not removed using nitric acid. The radiochemical procedure was tested using PROCORAD intercomparison exercises and PNI samples. (author)

Determination of 226Ra and 224Ra in sediments samples by liquid scintillation counting

International Nuclear Information System (INIS)

Villa, M.; Moreno, H.P.; Manjon, G.

2005-01-01

An experimental procedure has been developed for a rapid determination of the activity concentration of 226 Ra and 224 Ra in sediments by liquid scintillation counting. The importance of the method lies in its application to the measurement of sediments where the Ra-isotopes activity concentration has been increased due to an anthropomorphic enhancement based on releases of naturally occurring radioactive material (NORM). A sample pre-treatment, including a digestion with aqua regia and a precipitation of hydroxides, was applied to samples before the radium extraction, which was made by co-precipitation with barium. Measurements were done in a low background scintillation spectrometer Quantulus 1220, which can separate and detect simultaneously α and β particles. Additionally, some improvements are suggested for a better α and β interference correction of the results. The obtaining of radiochemical yields is also improved using 133 Ba as tracer, which decays by emission of conversion electrons and γ-rays; the wide range of radiochemical yields obtained confirms the need of this analyses. The procedure has been applied to the measurement of riverbed sediments from an estuary in the south-west of Spain, affected in the past by direct and indirect phosphogypsum discharges

Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

Energy Technology Data Exchange (ETDEWEB)

Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

2015-07-01

It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

Radioactivity measurements by liquid scintillation spectroscopy

International Nuclear Information System (INIS)

Cassette, Ph.

2004-01-01

The activity measurement techniques by liquid scintillation spectroscopy consist to mix the radioactive solution to measure with a scintillating liquid and to transform the ionizing radiations, resulting from decays, into light, detectable and quantifiable. The main advantages of these techniques are the easiness of preparation of the radioactive sources, the geometric efficiency of detection of 4π and the possibility of detection of low-level energy radiations. There are one of the only methods giving the possibility to measure the activity of pure β radionuclides; indeed, the nuclear disintegration is not accompanied of gamma radiations detectable by other techniques. There are one of the only methods too of measurement of radionuclides which disintegrate by electron capture and especially those leading to the emission of low-level energy ionizing radiations. Liquid scintillation spectroscopy can be used as an absolute method of activity measurement that is to say without the use of a calibration standard. The modern liquid scintillation counting devices can be very sensitive; the measurement of micro-activities being possible. Some of the applications of these activity measurement techniques are the carbon 14 dating and the geological tracing. Their main disadvantage is the global energetic yield which is low and variable in terms of the composition of the scintillation source necessitating to calculate the detection yield for each condition of measurement. (O.M.)

Primary standardization of {sup 152}Eu by 4πβ(LS) - γ (NaI) coincidence counting and CIEMAT-NIST method

Energy Technology Data Exchange (ETDEWEB)

Ruzzarin, A., E-mail: aruzzarin@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (LIN/PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear; Cruz, P.A.L. da; Ferreira Filho, A.L.; Iwahara, A. [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiações Ionizantes

2017-07-01

The 4πβ-γ coincidence counting and CIEMAT/NIST liquid scintillation method were used in the standardization of a solution of {sup 152}Eu. In CIEMAT/NIST method, measurements were performed in a Liquid Scintillation Counter model Wallac 1414. In the 4πβ-γ coincidence counting, the solution was standardized using a coincidence method with 'beta-efficiency extrapolation'. A simple 4πβ-γ coincidence system was used, with acrylic scintillation cell coupled to two coincident photomultipliers at 180° each other and NaI(Tl) detector. The activity concentrations obtained were 156.934 ± 0.722 and 157.403 ± 0.113 kBq/g, respectively, for CIEMAT/NIST and 4πβ-γ coincidence counting measurement methods. (author)

Basic principles of scintillation counting; Principes de Base du Comptage par Scintillations; Osnovnye printsipy stsintillyatsij; Principios fundamentales del recuento con aparatos de centelleo

Energy Technology Data Exchange (ETDEWEB)

Johns, H E; Cederlund, J F [Ontario Cancer Institute, Toronto (Canada)

1959-07-01

The effect of the energy of radiation, the crystal size, the collimation of the beam and scattering on the pulse-height distribution produced by monoenergetic radiation will be discussed. These aspects will be related to scintillation scanning. The effects of voltage on the operation of photomultiplier s and so-called plateaus will be dealt with. Glow-transfer tubes for counting will be dealt with and a useful substraction circuit for comparing the counting rate from two separate scintillation counters will be presented. (author) [French] Les auteurs examineront l'effet de l'energie du rayonnement, de la dimension du cristal, de la collimation du faisceau et de la diffusion sur la repartition de l'amplitude des impulsions dues au rayonnement monoenergetique, en rattachant l'etude de ces questions a l'exploration par scintillations. Ils etudieront egalement les effets de la tension sur le fonctionnement des photomultiplicateurs et des , ainsi que l'utilisation de pour le comptage; ils presenteront enfin un circuit de soustraction utile servant a comparer le taux de comptage de deux scintillometres distincts. (author) [Spanish] Los autores estudiaran el efecto que la energia de la radiacion, el tamano del cristal, la colimacion del haz y la dispersion ejercen sobre la distribucion de la amplitud de los impulsos debida a la radiacion monoenergetica, relacionando todas estas cuestiones con la exploracion mediante aparatos de centelleo. Examinaran tambien la influencia de las variaciones de tension sobre el funcionamiento de los fotomultiplicadores y sobre las denominadas , asi como los tubos luminiscentes de transmision para el recuento; por ultimo, presentaran un circuito de sustraccion que sirve para comparar el indice de recuento de dos contadores de centelleo distintos. (author) [Russian] Budet obsuzhdat'sya vliyanie ehnergii izlucheniya, velichiny kristalla, kollimirovaniya lucha i, nakonets, rasseyaniya na amplitudnoe

A liquid scintillation counter specifically designed for samples deposited on a flat matrix

International Nuclear Information System (INIS)

Potter, C.G.; Warner, G.T.

1986-01-01

A prototype liquid scintillation counter has been designed to count samples deposited as a 6x16 array on a flat matrix. Applications include the counting of labelled cells processed by a cell harvester from 96-well microtitration plates onto glass fibre filters and of DNA samples directly deposited onto nitrocellulose or nylon transfer membranes (e.g. 'Genescreen' NEN) for genetic studies by dot-blot hybridisation. The whole filter is placed in a bag with 4-12 ml of scintillant, sufficient to count all 96 samples. Nearest-neighbour intersample cross talk ranged from 0.004% for 3 H to 0.015% for 32 P. Background was 1.4 counts/min for glass fibre and 0.7 counts/min for 'Genescreen' in the 3 H channel: for 14 C the respective figures were 5.3 and 4.3 counts/min. Counting efficiency for 3 H-labelled cells on glass fibre was 54%(E 2 /B=2053) and 26% for tritiated thymidine spotted on 'Genescreen'(E 2 /B=980). Similar 14 C samples gave figures on 97%(E 2 /B=1775) and 81(E 2 B=1526) respectively. Electron emission counting from samples containing 125 I and 51 Cr was also possible. (U.K.)

Rapid determination of gross alpha and beta activity in seafood utilizing microwave digestion and liquid scintillation counting

International Nuclear Information System (INIS)

Daniel Sas; Jiri Janda; Alena Tokarova

2015-01-01

This paper describes a method for rapid determination of gross alpha and beta activity in seafood using liquid scintillation counting and microwave digestion for fast sample decomposition. The general group of seafood was divided into two groups based on its structure, whether it has shell or not. The selected group of radionuclides was chosen with respect to military significance, radiotoxicity, and possibility of potential misuse. 90 Sr and 239 Pu were selected as model radionuclides. (author)

High-pressure 3He gas scintillation neutron spectrometer

International Nuclear Information System (INIS)

Derzon, M.S.; Slaughter, D.R.; Prussin, S.G.

1985-10-01

A high-pressure, 3 He-Xe gas scintillation spectrometer has been developed for neutron spectroscopy on D-D fusion plasmas. The spectrometer exhibits an energy resolution of (121 +- 20 keV) keV (FWHM) at 2.5 MeV and an efficiency of (1.9 +- 0.4) x 10 -3 (n/cm 2 ) -1 . The contribution to the resolution (FWHM) from counting statistics is only (22 +- 3 keV) and the remainder is due predominantly to the variation of light collection efficiency with location of neutron events within the active volume of the detector

New procedure for the determination of radium in water by extraction of radon and application of integral counting with a liquid scintillation counter

Energy Technology Data Exchange (ETDEWEB)

Horiuchi, K [Tokyo Metropolitan Univ. (Japan). Faculty of Science; Murakami, Y [Kitasato Univ. (Japan). School of Hygienic Sciences

1981-05-01

A new Ra determination method is devised, storing the sample in a glass bottle with a Teflon stopper in an upside-down position, extracting Rn with liquid scintillator solution and combining integral counting with a liquid scintillation counter. This method realizes a high sensitivity of 5 x 10/sup -13/ Ci Ra, eliminates the tedious procedure of transferring Rn through the vacuum system to the detector and makes possible repeated determinations of Ra on the same sample without any further chemical treatment except extraction.

Optimised method for the routine determination of Technetium-99 in environmental samples by liquid scintillation counting

International Nuclear Information System (INIS)

Wigley, F.; Warwick, P.E.; Croudace, I.W.; Caborn, J.; Sanchez, A.L.

1999-01-01

A method has been developed for the routine determination of 99 Tc in a range of environmental matrices using 99m Tc (t 1/2 =6.06 h) as an internal yield monitor. Samples are ignited stepwise to 550C and the 99 Tc is extracted from the ignited residue with 8 M nitric acid. Many contaminants are co-precipitated with Fe(OH) 3 and the Tc in the supernatant is pre-concentrated and further purified using anion exchange chromatography. Final separation of Tc from Ru is achieved by extraction of Tc into 5% tri-n-octylamine in xylene from 2 M sulphuric acid. The xylene fraction is mixed directly with a commercial liquid scintillant cocktail. The chemical yield is determined through the measurement of 99m Tc by gamma spectrometry and the 99 Tc activity is measured using liquid scintillation counting after a further two weeks to allow decay of the 99m Tc activity. Typical recoveries for this method are in the order 70-95%. The method has a detection limit of 1.7 Bq kg -1 based on a 2 h count time and a 10 g sample size. The chemical separation for 24 samples of sediment or marine biota can be completed by one analyst in a working week. A further week is required to allow the samples to decay before determination. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

A simple method for calibration of Lucas scintillation cell counting system for measurement of 226Ra and 222Rn

Directory of Open Access Journals (Sweden)

N.K. Sethy

2014-10-01

Full Text Available Known quantity of radium from high grade ore solution was chemically separated and carefully kept inside the cavity of a Lucas Cell (LC. The 222Rn gradually builds up and attain secular equilibrium with its parent 226Ra. This gives a steady count after a suitable buildup period (>25 days. This secondary source was used to calibrate the radon counting system. The method is validated in by comparison with identical measurement with AlphaGuard Aquakit. The radon counting system was used to evaluate dissolved radon in ground water sample by gross alpha counting in LC. Radon counting system measures the collected radon after a delay of >180 min by gross alpha counting. Simultaneous measurement also carried out by AlphaGuard Aquakit in identical condition. AlphaGuard measures dissolved radon from water sample by constant aeration in a closed circuit without giving any delay. Both the methods are matching with a correlation coefficient of >0.9. This validates the calibration of Lucas scintillation cell counting system by designed encapsulated source. This study provides an alternative for calibration in absence of costly Radon source available in the market.

An improved method for {sup 85}Kr analysis by liquid scintillation counting and its application to atmospheric {sup 85}Kr determination

Energy Technology Data Exchange (ETDEWEB)

Momoshima, Noriyuki, E-mail: momoshima.noriyuki.551@m.kyushu-u.ac.j [Radioisotope Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Inoue, Fumio [Graduate School of Science, Kyushu University, 6-10-1Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Sugihara, Shinji [Radioisotope Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Shimada, Jun [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Taniguchi, Makoto [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan)

2010-08-15

Atmospheric {sup 85}Kr concentration at Fukuoka, Japan was determined by an improved {sup 85}Kr analytical method using liquid scintillation counting (LSC). An average value of 1.54 {+-} 0.05 Bq m{sup -3} was observed in 2008, which is about two times that measured in 1981 at Fukuoka, indicating a 29 mBq y{sup -1} rate of increase as an average for these 27 years. The analytical method developed involves collecting Kr from air using activated charcoal at liquid N{sub 2} temperature and purifying it using He at dry ice temperature, followed by Kr separation by gas chromatography. An overall Kr recovery of 76.4 {+-} 8.1% was achieved when Kr was analyzed in 500-1000 l of air. The Kr isolated by gas chromatography was collected on silica gel in a quartz glass vial cooled to liquid N{sub 2} temperature and the activity of {sup 85}Kr was measured with a low-background LS counter. The detection limit of {sup 85}Kr activity by the present analytical method is 0.0015 Bq at a 95% confidence level, including all propagation errors, which is equivalent with {sup 85}Kr in 1.3 l of the present air under the analytical conditions of 72.1% counting efficiency, 0.1597 cps background count rate, and 76.4% Kr recovery.

SCINFI II A program to calculate the standardization curve in liquid scintillation counting

Energy Technology Data Exchange (ETDEWEB)

Grau Carles, A.; Grau Malonda, A.

1985-07-01

A code, SCINFI II, written in BASIC, has been developed to compute the efficiency-quench standardization curve for any beta radionuclide. The free parameter method has been applied. The program requires the standardization curve for 3{sup H} and the polynomial or tabulated relating counting efficiency as figure of merit for both 3{sup H} and the problem radionuclide. The program is applied to the computation, of the counting efficiency for different values of quench when the problem is 14{sup C}. The results of four different computation methods are compared. (Author) 17 refs.

SCINFI II A program to calculate the standardization curve in liquid scintillation counting

International Nuclear Information System (INIS)

Grau Carles, A.; Grau Malonda, A.

1985-01-01

A code, SCINFI II, written in BASIC, has been developed to compute the efficiency-quench standardization curve for any beta radionuclide. The free parameter method has been applied. The program requires the standardization curve for 3 H and the polynomial or tabulated relating counting efficiency as figure of merit for both 3 H and the problem radionuclide. The program is applied to the computation, of the counting efficiency for different values of quench when the problem is 14 C . The results of four different computation methods are compared. (Author) 17 refs

A Performance Comparison of Nine Selected Liquid Scintillation Cocktails

Energy Technology Data Exchange (ETDEWEB)

Verrezen, F; Loots, H; Hurtgen, Ch

2008-06-15

In the selection of a suitable liquid scintillation (LSC) cocktail, the primary aspects taken into consideration are overall cocktail performance and specific laboratory needs. Overall performance of 9 selected, commercially available LSC cocktails was assessed by studying parameters of importance for the requirements of the Laboratory for Low Level Radioactivity Measurements of SCK-CEN: sample load capacity, sample compatibility, influence of sample load on counting efficiency, background count rate, figure of merit, quench resistance, sample stability and alpha/beta separation characteristics. The cocktails tested were EcoscintA, Insta Gel Plus, OptiPhase Hisafe3, OptiPhase Trisafe, Ready Gel, SafeScint 1:1, Ultima Gold, Ultima Gold LLT, and Ultima Gold XR. For the data acquisition a Packard TriCarb Model 1900CA and a Quantulus 1220 liquid scintillation counter is used. All samples were prepared in either 20 mL low potassium, borosilicate glass vials or 20 mL high density, polyethylene vials. The aim of this study was to determine a single cocktail that best suits all measurement requirements of the liquid scintillation laboratory at SCK-CEN for the determination of low levels of radioactivity in biological and environmental samples. As a conclusion, Optiphase HiSafe 3 was confirmed to be the optimal cocktail for the laboratory.

A Performance Comparison of Nine Selected Liquid Scintillation Cocktails

International Nuclear Information System (INIS)

Verrezen, F.; Loots, H.; Hurtgen, Ch.

2008-01-01

In the selection of a suitable liquid scintillation (LSC) cocktail, the primary aspects taken into consideration are overall cocktail performance and specific laboratory needs. Overall performance of 9 selected, commercially available LSC cocktails was assessed by studying parameters of importance for the requirements of the Laboratory for Low Level Radioactivity Measurements of SCK-CEN: sample load capacity, sample compatibility, influence of sample load on counting efficiency, background count rate, figure of merit, quench resistance, sample stability and alpha/beta separation characteristics. The cocktails tested were EcoscintA, Insta Gel Plus, OptiPhase Hisafe3, OptiPhase Trisafe, Ready Gel, SafeScint 1:1, Ultima Gold, Ultima Gold LLT, and Ultima Gold XR. For the data acquisition a Packard TriCarb Model 1900CA and a Quantulus 1220 liquid scintillation counter is used. All samples were prepared in either 20 mL low potassium, borosilicate glass vials or 20 mL high density, polyethylene vials. The aim of this study was to determine a single cocktail that best suits all measurement requirements of the liquid scintillation laboratory at SCK-CEN for the determination of low levels of radioactivity in biological and environmental samples. As a conclusion, Optiphase HiSafe 3 was confirmed to be the optimal cocktail for the laboratory.

Test use of 'Ready Cap' for radiation measurement with a liquid scintillation counter

International Nuclear Information System (INIS)

Kato, Takahisa; Saito, Kazumi; Kurihara, Norio

1989-01-01

We tested the performance of 'Ready Cap' which can be used in place of liquid scintillation cocktails to measure the activity of 3 H and 14 C with a liquid scintillation counter, and observed satisfactory results on counting efficiencies for these nuclides. We could correct color-quenching with Ready Cap either by a method of the gravity-center of β-ray spectrum or by an external standard method that uses the external irradiation from bottom of the sample. Although there are several problems such as limitation of the maximum sample volumes (<200 μl) and sample preparation procedures (drying the sample solution), we can conveniently employ Ready Cap in some aspects of activity counting because of the easy disposal procedure of the radioactive waste resulting from it. (author)

Radiation damage studies on new liquid scintillators and liquid-core scintillating fibers

International Nuclear Information System (INIS)

Golovkin, S.V.

1994-01-01

The radiation resistant of some new liquid scintillation and capillaries filled with liquid scintillators has been presented. It was found that scintillation efficiency of the scintillator based on 1-methyl naphthalene with a new R39 only by 10% at the dose of 190 Mrad and the radiation resistance of thin liquid-core scintillating was decreased fibers exceeded 60 Mrad. 35 refs

Efficiency of a bismuth-germanate scintillator: comparison of Monte Carlo calculations with measurements

International Nuclear Information System (INIS)

Hsu, H.H.; Dowdy, E.J.; Estes, G.P.; Lucas, M.C.; Mack, J.M.; Moss, C.E.; Hamm, M.E.

1983-01-01

Monte Carlo calculations of a bismuth-germanate scintillator's efficiency agree closely with experimental measurements. For this comparison, we studied the absolute gamma-ray photopeak efficiency of a scintillator (7.62 cm long by 7.62 cm in diameter) at several gamma-ray energies from 166 to 2615 keV at distances from 0.5 to 152.4 cm. Computer calculations were done in a two-dimensional cylindrical geometry with the Monte Carlo coupled photon-electron code CYLTRAN. For the experiment we measured 11 sources with simple spectra and precisely known strengths. The average deviation between the calculations and the measurements is 3%. Our calculated results also closely agree with recently published calculated results

Study of the functional characteristics of a NaI(Tl) scintillator gamma spectrometer

International Nuclear Information System (INIS)

Jesus Barbosa, S. de.

1983-01-01

Functional characteristics (resolution, stability, linearity, counting efficiency) of a NaI(Tl) scintillator gamma spectrometer were studied. Diagrams were plotted and several standard sources ( 241 Am, 109 Cd, 57 Co, 137 Cs, 54 Mn, 22 Na) with gamma energies ranging from 60 to 1275 KeV were used. (C.L.B.) [pt

The accurate measurement of the disintegration rate of 55Fe using an internal liquid scintillation counter

International Nuclear Information System (INIS)

Botha, S.M.

1979-01-01

As the well-known 4πX-γ-coincidence method cannot be used directly to find the disintegration rate of 55 Fe, another method was developed in which a tracer nuclide, possessing coincident gamma radiation, was used. It was now possible to determine the disintegration rate indirectly by the coincidence method using an internal liquid scintillation counter. 54 Mn and 51 Cr which lie in the immediate vicinity of iron in the series of nuclides, are suitable tracers. They are also electron capture nuclides, but decaying to an excited state, were counted by the 4πX-γ-coincidence method. A mixed source, containing 55 Fe and the tracer, was also counted by the coincidence method so that the 4π-counting rate of 55 Fe was obtained as function of the tracer's counting efficiency. It was also essential to find a relationship between the counting efficiencies of the liquid scintillation counter for 55 Fe and the tracer. This relationship is called the effeciency function. Efficiency functions were calculated for 55 Fe and 54 Mn as well as for 55 Fe and 51 Cr. Finally the radioactive concentration of a solution of 55 Fe had been carefully determined by using 54 Mn and 51 Cr tracers. The results for the two different tracers agreed within the statistical uncertainty of 0,4%. The systematic uncertainty on the final results was estimated as 0,17%

Liquid scintillation in medical diagnosis

International Nuclear Information System (INIS)

Painter, K.

1976-01-01

With the tremendous increase in the application of radioassay, particularly radioimmunoassay, in the clinical laboratory liquid scintillation counting became an indispensable tool in diagnostic medicine. Few publications, however, have concerned themselves with problem areas which occur with the method in the clinical laboratory. The purpose of this presentation is to summarize our experiences with the liquid scintillation technique in the clinical situation

Scintillation properties of acrylate based plastic scintillator by photoploymerization method

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hwan [Dept. of Radiological Science, Cheongju University, Cheongju (Korea, Republic of); Lee, Joo Il [Dept. of of Radiology, Daegu Health College, Daegu (Korea, Republic of)

2016-12-15

In this study, we prepared and characterized a acrylate based UV-curable plastic scintillator. It was used co-polymers TMPTA, DHPA and Ultima GoldTM LLT organic scintillator. The emission spectrum of the plastic scintillator was located in the range of 380⁓520 nm, peaking at 423 nm. And the scintillator is more than 50% transparent in the range of 400⁓ 800 nm. The emission spectrum is well match to the quantum efficiency of photo-multiplier tube and the fast decay time of the scintillation is 12 ns, approximately. This scintillation material provides the possibility of combining 3D printing technology, and then the applications of the plastic scintillator may be expected in human dosimetry etc.

Highly efficient solid-state neutron scintillators based on hybrid sol-gel nanocomposite materials

International Nuclear Information System (INIS)

Kesanli, Banu; Hong, Kunlun; Meyer, Kent; Im, Hee-Jung; Dai, Sheng

2006-01-01

This research highlights opportunities in the formulation of neutron scintillators that not only have high scintillation efficiencies but also can be readily cast into two-dimensional detectors. Series of transparent, crack-free monoliths were prepared from hybrid polystyrene-silica nanocomposites in the presence of arene-containing alkoxide precursor through room temperature sol-gel processing. The monoliths also contain lithium-6 salicylate as a target material for neutron-capture reactions and amphiphilic scintillator solution as a fluorescent sensitizer. Polystyrene was functionalized by trimethoxysilyl group in order to enable the covalent incorporation of aromatic functional groups into the inorganic sol-gel matrices for minimizing macroscopic phase segregation and facilitating lithium-6 doping in the sol-gel samples. Neutron and alpha responses of these hybrid polystyrene-silica monoliths were explored

Beta-gamma counting system for Xe fission products

International Nuclear Information System (INIS)

Reeder, P.L.; Bowyer, T.W.; Perkins, R.W.

1998-01-01

A beta-gamma coincidence counting system has been developed for automated analysis of Xe gas samples separated from air. The Xe gas samples are contained in a cylindrical plastic scintillator cell located between two NaI(Tl) scintillation detectors. The X-ray and gamma spectra gated by coincident events in the plastic scintillator cell are recorded for each NaI(Tl) crystal. The characteristic signatures of the 131m Xe, 133g Xe, 133m Xe, and 135g Xe isotopes of interest for nuclear test-ban verification as well as the procedures and results of absolute efficiency measurements are described. A NaI(Tl) crystal with provision for 4 sample cells has been implemented for the system to be deployed in the field. Examples of data on ambient air samples in New York City obtained with the field prototype are presented. (author)

Background characterization in a liquid scintillation spectrometer

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Los Arcos, J.M.; Jimenez de Mingo, A.

1995-01-01

An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0 - 20 KeV, 0 - 800 KeV and 0 - 2 MeV, for volume between 2 and 20 mi of three commercial scintillators, Hisafe II, Ultima-Gold and Instagel, and quenching degree in the interval equivalent to 50% - 3% tritium efficiency. This procedure was tested with standard samples of 3H, and led to average discrepancies less than 10% for activity ≥0,6 Bq, against conventional methods for which the discrepancies are twice on average. (Author) 10 refs

Background characterization in a liquid scintillation spectrometer

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Los arcos, J.M.; Jimenez de Mingo, A.

1995-01-01

An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0-20 KeV, 0-800 KeV and 0-2 MeV, for volume between 2 and 20 ml of three commercial scintillators, Hisafe II, Ultima-gold and Instagel, and quenching degree in the interval equivalent to 50%-3% tritium efficiency. This procedure was tested with standard samples of ''3 H, and led to average discrepancies less than 10% for activity => 0,6 Bq, against conventional methods for which the discrepancies are twice on average

Liquid scintillation alpha particle spectrometry. Progress report

International Nuclear Information System (INIS)

Bell, L.L.; Hakooz, S.A.; Johnson, L.O.; Nieschmidt, E.B.; Meikrantz, D.H.

1979-12-01

Objective to develop a technique whereby Pu may be put into solution, extracted by solvent extraction into a suitable extractive scintillant and subsequently counted. Presented here are results of attempts to separate beta and alpha activities through pulse shape discrimination. A qualitative discussion is given which yields alpha particle peak widths, resolution and response. The detection efficiency for alpha particles in a liquid scintillant is 100%. Present detection sensitivities of the equipment being used are: 4.5 x 10 -6 μCi (100 s), 1.2 x 10 -6 μCi (1000 s), and 4.0 x 10 -7 μCi (10,000 s) at the 3 sigma level. The detectability of a particular alpha-emitting species is strongly dependent upon the population of other species. The ability to discriminate depends upon the system resolution. 14 figures, 2 tables

Some applications of Photon/Electron-Rejecting Alpha Liquid Scintillation (PERALS) spectrometry to the assay of alpha emitters

International Nuclear Information System (INIS)

McDowell, W.J.; Case, G.N.

1988-01-01

The combination of certain solvent extraction separations and a special kind of liquid scintillation detector and electronics designed for alpha spectrometry allows some highly accurate, yet simple determinations of alpha-emitting nuclides. Counting efficiency is 99.68% with backgrounds of 99.95%. The Photon/Electron Rejecting Alpha Liquid Scintillation (PERALS) equipment is described and procedures for the separation and determination of uranium, thorium, plutonium, polonium, radium, and trivalent actinides are outlined. 25 refs., 10 figs., 1 tab

Application of the efficiency tracing method to the liquid scintillation metrology of 3H and 14C dual-labelled samples

International Nuclear Information System (INIS)

Martin-Casallo, M. T.; Los Arcos, J. M.; Grau, A.

1989-01-01

Two calculation procedures have been tested for the application of the efficiency tracing method to the activity determination of 3H and 14C dual- -labelled samples in the liquid scintillation metrology. A procedure Ieads to the statement of a linear equations system as a function of the quenching parameter, while the other one uses a least-square algorithm to fit the total count rate against the quenching parameter. The first procedure is strongly sensitive to the statistical uncertainty on the partial efficiencies and produces discrepancies which may reach more than 100% compared to the real values. The second procedure leads to more reliable results, showing discrepancies between 0.1% and 0.6% for the 3H activity and between 0.6% and 5% for the 14C activity, as that the efficiency tracing method can be applied to the metro- logy of dual-labelled samples of 3H and 14C by means of this procedure. (Author) 7 refs

Timing performance of ZnO:Ga nanopowder composite scintillators

Energy Technology Data Exchange (ETDEWEB)

Turtos, Rosana M. [Universita degli Studi di Milano-Bicocca, Milano (Italy); Gundacker, Stefan; Lucchini, Marco T.; Lecoq, Paul; Auffray, Etiennette [CERN, Geneva (Switzerland); Prochazkova, Lenka; Cuba, Vaclav [Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Prague (Czech Republic); Buresova, Hana [Nuvia a.s, Kralupy nad Vltavou (Czech Republic); Mrazek, Jan [Institute of Photonics and Electronics AS CR, Prague (Czech Republic); Nikl, Martin [Institute of Physics of the AS CR, Prague (Czech Republic)

2016-11-15

The implementation of nanocrystal-based composite scintillators as a new generation of ultrafast particle detectors is explored using ZnO:Ga nanopowder. Samples are characterized with a spectral-time resolved photon counting system and pulsed X-rays, followed by coincidence time resolution (CTR) measurements under 511 keV gamma excitation. Results are comparable to CTR values obtained using bulk inorganic scintillators. Bringing the ZnO:Ga nanocrystal's timing performance to radiation detectors could pave the research path towards sub-20 ps time resolution as shown in this contribution. However, an efficiency boost when placing nanopowders in a transparent host constitutes the main challenge in order to benefit from sub-nanosecond recombination times. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Scintillation efficiency of nuclear recoil in liquid xenon

CERN Document Server

Arneodo, F; Badertscher, A; Benetti, P; Bernardini, E; Bettini, A; Borio di Tigliole, A A; Brunetti, R; Bueno, A G; Calligarich, E; Campanelli, M; Carpanese, C; Cavalli, D; Cavanna, F; Cennini, P; Centro, Sandro; Cesana, A; Cline, D; De Mitri, I; Dolfini, R; Ferrari, A; Gigli-Berzolari, A; Matthey, C; Mauri, F; Mazza, D; Mazzone, L; Meng, G; Montanari, C; Nurzia, G; Otwinowski, S; Palamara, O; Pascoli, D; Pepato, Adriano; Petrera, S; Periale, L; Piano Mortari, G; Piazzoli, A; Picchi, P; Pietropaolo, F; Rancati, T; Rappoldi, A; Raselli, G L; Rebuzzi, D; Revol, Jean Pierre Charles; Rico, J; Rossella, M; Rossi, C; Rubbia, André; Rubbia, Carlo; Sala, P; Scannicchio, D A; Sergiampietri, F; Suzuki, S; Terrani, M; Tian, W; Ventura, Sandro; Vignoli, C; Wang, H; Woo, J; Xu, Z

2000-01-01

We present the results of a test done with a Liquid Xenon (LXe) detector for 'Dark Matter' search, exposed to a neutron beam to produce nuclear recoil events simulating those which would be generated by WIMP's elastic scattering. The aim of the experiment was to measure directly the scintillation efficiency of nuclear recoil. The nuclear recoil considered in the test was in the tens of keV range. The ratio of measured visible energy over the true recoil energy was evaluated to be about 20%, in good agreement with the theoretical predictions.

Application of a free parameter model to plastic scintillation samples

Energy Technology Data Exchange (ETDEWEB)

Tarancon Sanz, Alex, E-mail: alex.tarancon@ub.edu [Departament de Quimica Analitica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Kossert, Karsten, E-mail: Karsten.Kossert@ptb.de [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany)

2011-08-21

In liquid scintillation (LS) counting, the CIEMAT/NIST efficiency tracing method and the triple-to-double coincidence ratio (TDCR) method have proved their worth for reliable activity measurements of a number of radionuclides. In this paper, an extended approach to apply a free-parameter model to samples containing a mixture of solid plastic scintillation microspheres and radioactive aqueous solutions is presented. Several beta-emitting radionuclides were measured in a TDCR system at PTB. For the application of the free parameter model, the energy loss in the aqueous phase must be taken into account, since this portion of the particle energy does not contribute to the creation of scintillation light. The energy deposit in the aqueous phase is determined by means of Monte Carlo calculations applying the PENELOPE software package. To this end, great efforts were made to model the geometry of the samples. Finally, a new geometry parameter was defined, which was determined by means of a tracer radionuclide with known activity. This makes the analysis of experimental TDCR data of other radionuclides possible. The deviations between the determined activity concentrations and reference values were found to be lower than 3%. The outcome of this research work is also important for a better understanding of liquid scintillation counting. In particular the influence of (inverse) micelles, i.e. the aqueous spaces embedded in the organic scintillation cocktail, can be investigated. The new approach makes clear that it is important to take the energy loss in the aqueous phase into account. In particular for radionuclides emitting low-energy electrons (e.g. M-Auger electrons from {sup 125}I), this effect can be very important.

Monte Carlo simulation of neutron detection efficiency for NE213 scintillation detector

International Nuclear Information System (INIS)

Xi Yinyin; Song Yushou; Chen Zhiqiang; Yang Kun; Zhangsu Yalatu; Liu Xingquan

2013-01-01

A NE213 liquid scintillation neutron detector was simulated by using the FLUKA code. The light output of the detector was obtained by transforming the secondary particles energy deposition using Birks formula. According to the measurement threshold, detection efficiencies can be calculated by integrating the light output. The light output, central efficiency and the average efficiency as a function of the front surface radius of the detector, were simulated and the results agreed well with experimental results. (authors)

Mass counting of radioactivity samples

International Nuclear Information System (INIS)

Oesterlin, D.L.; Obrycki, R.F.

1977-01-01

A method and apparatus for concurrently counting a plurality of radioactive samples is claimed. The position sensitive circuitry of a scintillation camera is employed to sort electrical pulses resulting from scintillations according to the geometrical locations of scintillations causing those pulses. A scintillation means, in the form of a scintillating crystal material or a liquid scintillator, is positioned proximate to an array of radioactive samples. Improvement in the accuracy of pulse classification may be obtained by employing collimating means. If a plurality of scintillation crystals are employed to measure the iodine-125 content of samples, a method and means are provided for correcting for variations in crystal light transmission properties, sample volume, and sample container radiation absorption. 2 claims, 7 drawing figures

Scintillation counter, segmented shield

International Nuclear Information System (INIS)

Olson, R.E.; Thumim, A.D.

1975-01-01

A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

Detection and counting systems

International Nuclear Information System (INIS)

Abreu, M.A.N. de

1976-01-01

Detection devices based on gaseous ionization are analysed, such as: electroscopes ionization chambers, proportional counters and Geiger-Mueller counters. Scintillation methods are also commented. A revision of the basic concepts in electronics is done and the main equipment for counting is detailed. In the study of gama spectrometry, scintillation and semiconductor detectors are analysed [pt

Comparison of image uniformity with photon counting and conventional scintillation single-photon emission computed tomography system: A Monte Carlo simulation study

Energy Technology Data Exchange (ETDEWEB)

Kim, Ho Chul; Lee, Young Jin [Dept. of Radiological Science, Eulji University, Seongnam (Korea, Republic of); Kim, Hee Joung; Kim, Kyuseok; Lee, Min Hee [Yonsei University, Wonju (Korea, Republic of)

2017-06-15

To avoid imaging artifacts and interpretation mistakes, an improvement of the uniformity in gamma camera systems is a very important point. We can expect excellent uniformity using cadmium zinc telluride (CZT) photon counting detector (PCD) because of the direct conversion of the gamma rays energy into electrons. In addition, the uniformity performance such as integral uniformity (IU), differential uniformity (DU), scatter fraction (SF), and contrast-to-noise ratio (CNR) varies according to the energy window setting. In this study, we compared a PCD and conventional scintillation detector with respect to the energy windows (5%, 10%, 15%, and 20%) using a {sup 99m}Tc gamma source with a Geant4 Application for Tomography Emission simulation tool. The gamma camera systems used in this work are a CZT PCD and NaI(Tl) conventional scintillation detector with a 1-mm thickness. According to the results, although the IU and DU results were improved with the energy window, the SF and CNR results deteriorated with the energy window. In particular, the uniformity for the PCD was higher than that of the conventional scintillation detector in all cases. In conclusion, our results demonstrated that the uniformity of the CZT PCD was higher than that of the conventional scintillation detector.

Fluorescent organic dyes as radiation converters in scintillation counting and laser techniques

International Nuclear Information System (INIS)

Guesten, H.

1989-01-01

PMP (1-phenyl-3-mesityl-2-pyrazoline) was selected as color quenching from the category of the sterically hindered 1,3-diphenyl-2-pyrazoline by means of comparative optimization between photo-physical and scintillation-spectroscopic and chemical properties and the costs of synthesis. It is applied in liquid scintillation detectors for the detection of β (T, C-14) and in large-volume liquid scintillators for the detection of neutrinos (Rutherford Lab.). (HP) [de

222Rn determination in water and brine samples using liquid scintillation spectrometry

International Nuclear Information System (INIS)

Oliveira, Thiago C.; Oliveira, Arno H.

2017-01-01

Liquid scintillation spectrometry (LSC) is the most common technique used for 222 Rn determination in environmental aqueous sample. In this study, the performance of water-miscible (Ultima Gold AB) and immiscible (Optiscint) liquid scintillation cocktails has been compared for different matrices. 241 Am, 90 Sr and 226 Ra standard solutions were used for LSC calibration. 214 Po region was defined as better for both cocktails. Counting efficiency of 76 % and optimum PSA level of 95 for Ultima Gold AB cocktail, and counting efficiency of 82 % and optimum PSA level of 85 for Optiscint cocktail were obtained. Both cocktails showed similar results when applied for 222 Rn activity determination in water and brine samples. However the Optiscint is recommended due to its quenching resistance. Limit of detection of 0.08 and 0.06 Bq l -1 were obtained for water samples using a sample:cocktail ratio of 10:12 mL for Ultima Gold AB and Optiscint cocktails, respectively. Limit of detection of 0.08 and 0.04 Bq l -1 were obtained for brine samples using a sample:cocktail ratio of 8:12 mL for Ultima Gold AB and Optiscint cocktails, respectively. (author)

Scintillation detector with anticoincidence shield for determination of the radioactive concentration of standard solutions

International Nuclear Information System (INIS)

Broda, R.; Radoszewski, T.

1982-01-01

The construction and parameters of the prototype liquid scintillation detector for disintegration rate determination of standard solutions is described. The detector is equipped with a liquid scintillation anticoincidence shield with a volume of 40 l. The instrument is placed in the building of the Radioisotope Production and Distribution Centre in the Institute of Nuclear Research at Swierk. The results of instrument background reduction are described. The counting efficiency of several beta-emitters 3 H, 63 Ni, 14 C and 90 Sr + 90 Y is given, as well as the examples of a disintegration rate determination of low radioactivity concentration of standard solutions. (author)

Stability and reproducibility of gel-suspension samples for the liquid scintillation counting of 14C using N-lauroyl-L-glutamic-α,γ-dibutylamide

International Nuclear Information System (INIS)

Wakabayashi, G.; Ohura, H.; Okai, T.; Matoba, M.

1999-01-01

Stability and reproducibility of gel-suspension method for 14 C activity measurement. Commercially available gelling agent, N-lauroyl-L-glutamic-α,γ-dibutylamide, was used for the gel-formation of the samples. No change of the counting rate for the gel-suspension sample was observed for more than 2 years after the sample preparation. Four samples used for checking the reproducibility of the sample preparation method. The same values were obtained for the counting rate of 14 C activity within the counting error. No change of the counting rate was observed for the 're-gelated' sample. These results show that the gel-suspension method is appropriate for the 14 C activity measurement by the liquid scintillation method and is useful for a long-term preservation of the sample for repeated measurement. (author)

Calculation of efficiency of high-energy neutron detection by plastic scintillators

International Nuclear Information System (INIS)

Telegin, Yu.N.

1977-01-01

A computer was used to calculate neutron (5-30O MeV) registration effeciencies with plastic scintillators 2,5,10, 20,30,40 and 50 cm thick. The results are shown in the form of tables. The contributions to efficiency of various processes have been analysed. The calculation results may be used in planning experiments with neutron counters

Scintillation proximity assay

International Nuclear Information System (INIS)

Hart, H.

1980-01-01

In a method of immunological assay two different classes of particles which interact at short distances to produce characteristic detectable signals are employed in a modification of the usual latex fixation test. In one embodiment an aqueous suspension of antigen coated tritiated latex particles (LH) and antigen coated polystyrene scintillant particles (L*) is employed to assay antibody in the aqueous medium. The amount of (LH) (L*) dimer formation and higher order aggregation induced and therefore the concentration of antibody (or antigen) present which caused the aggregation can be determined by using standard liquid scintillation counting equipment. (author)

Determination of 63Ni and 55Fe in nuclear waste samples using radiochemical separation and liquid scintillation counting

DEFF Research Database (Denmark)

Hou, Xiaolin; Frøsig Østergaard, L.; Nielsen, S.P.

2005-01-01

An analytical method for the determination of Ni-63 and Fe-55 in nuclear waste samples such as graphite, heavy concrete, aluminium and lead was developed. Different decomposition methods (i.e. ashing, acid digestion and alkali fusion) were investigated for the decomposition of the samples...... by extraction chromatography. The purified Ni-63 and Fe-55 was then measured by liquid scintillation counting. The chemical yields of the separation procedures for Fe-55 and Ni-63 are above 90% and the decontamination factors for all interfering radionuclides are more than 10(5). The detection limits...

Free parameter, figure of merit and ionization quench in liquid scintillation counting

International Nuclear Information System (INIS)

Carles, P. Grau; Malonda, A. Grau

2001-01-01

A statistical study of the detection process demonstrates that the free parameter is essential to compute the counting efficiency in both CIEMAT/NIST and TDCR methods. An analysis of the computed counting efficiencies shows the uselessness of old definition of the figure of merit. A new definition is required and we adopt the idea of taking quantities related with the output of the photomultiplier. In addition, we justify the application of the chemical quenching simulation with the electronic variation of the photomultiplier gain. Finally, we describe a new procedure to determine the figure of merit and the optimum ionization-quenching factor from the pulse spectrum of different radionuclides. The robustness of the new procedure is tested with three different sets of stopping power for low-energy electrons

Chemical and colour quenching in liquid scintillation counting; Estudio de la extincion quimica y por color en centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Scott, P E; Grau, A

1987-07-01

Chemical and colour quenching for H-3 and C-14 was studied. The method includes spectral analysis of colouring agents; methyl red, (4'-dimethylamine-azobenzene 2-carboxylic acid) dimethyl yellow (4'-dimethylamine-azobenzene) and malachite green (methane, bis .(4-dimethyl aminophenyl) - (phenyl)). External standard channels ratio was applied for the liquid scintillation counting of samples. The introduction of an isolated external standard seems to be a strong tool for the correction of chemical and colour quenching curves. (Author) 12 refs.

Chemical and colour quenching in liquid scintillation counting; Estudio de la extincion quimica y por color en centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Scott, P. E.; Grau, A.

1987-07-01

Chemical and colour quenching for H-3 and C-14 was studied. The method includes spectral analysis of colouring agents; methyl red, (4'-dimethylamine-azobenzene 2-carboxylic acid) dimethyl yellow (4'-dimethylamine-azobenzene) and malachite green (methane, bis .(4-dimethyl aminophenyl) - (phenyl)). External standard channels ratio was applied for the liquid scintillation counting of samples. The introduction of an isolated external standard seems to be a strong tool for the correction of chemical and colour quenching curves. (Author) 12 refs.

Digital liquid-scintillation counting and effective pulse-shape discrimination with artificial neural networks

International Nuclear Information System (INIS)

Langrock, Gert; Wiehl, Norbert; Kling, Hans-Otto; Mendel, Matthias; Naehler, Andrea; Tharun, Udo; Eberhardt, Klaus; Trautmann, Norbert; Kratz, Jens Volker

2015-01-01

A typical problem in low-level liquid scintillation (LS) counting is the identification of α particles in the presence of a high background of β and γ particles. Especially the occurrence of β-β and β-γ pile-ups may prevent the unambiguous identification of an α signal by commonly used analog electronics. In this case, pulse-shape discrimination (PSD) and pile-up rejection (PUR) units show an insufficient performance. This problem was also observed in own earlier experiments on the chemical behaviour of transactinide elements using the liquid-liquid extraction system SISAK in combination with LS counting. α-particle signals from the decay of the transactinides could not be unambiguously assigned. However, the availability of instruments for the digital recording of LS pulses changes the situation and provides possibilities for new approaches in the treatment of LS pulse shapes. In a SISAK experiment performed at PSI, Villigen, a fast transient recorder, a PC card with oscilloscope characteristics and a sampling rate of 1 giga samples s -1 (1 ns per point), was used for the first time to record LS signals. It turned out, that the recorded signals were predominantly α β-β and β-γ pile up, and fission events. This paper describes the subsequent development and use of artificial neural networks (ANN) based on the method of 'back-propagation of errors' to automatically distinguish between different pulse shapes. Such networks can 'learn' pulse shapes and classify hitherto unknown pulses correctly after a learning period. The results show that ANN in combination with fast digital recording of pulse shapes can be a powerful tool in LS spectrometry even at high background count rates.

Rapid bioassay method for estimation of 90Sr in urine samples by liquid scintillation counting

International Nuclear Information System (INIS)

Wankhede, Sonal; Chaudhary, Seema; Sawant, Pramilla D.

2018-01-01

Radiostrontium (Sr) is a by-product of the nuclear fission of uranium and plutonium in nuclear reactors and is an important radionuclide in spent nuclear fuel and radioactive waste. Rapid bioassay methods are required for estimating Sr in urine following internal contamination. Decision regarding medical intervention, if any can be based upon the results of urinalysis. The present method used at Bioassay Laboratory, Trombay is by Solid Extraction Chromatography (SEC) technique. The Sr separated from urine sample is precipitated as SrCO 3 and analyzed gravimetrically. However, gravimetric procedure is time consuming and therefore, in the present study, feasibility of Liquid Scintillation Counting for direct detection of radiostrontium in effluent was explored. The results obtained in the present study were compared with those obtained using gravimetric method

Activity measurements of radioactive solutions by liquid scintillation counting and pressurized ionization chambers and Monte Carlo simulations of source-detector systems for metrology

International Nuclear Information System (INIS)

Amiot, Marie-Noelle

2013-01-01

The research works 'Activity measurements of radioactive solutions by liquid scintillation and pressurized ionization chambers and Monte Carlo simulations of source-detector systems' was presented for the graduation: 'Habilitation a diriger des recherches'. The common thread of both themes liquid scintillation counting and pressurized ionization chambers lies in the improvement of the techniques of radionuclide activity measurement. Metrology of ionization radiation intervenes in numerous domains, in the research, in the industry including the environment and the health, which are subjects of constant concern for the world population these last years. In this big variety of applications answers a large number of radionuclides of diverse disintegration scheme and under varied physical forms. The presented works realized within the National Laboratory Henri Becquerel have for objective to assure detector calibration traceability and to improve the methods of activity measurements within the framework of research projects and development. The improvement of the primary and secondary activity measurement methods consists in perfecting the accuracy of the measurements in particular by a better knowledge of the parameters influencing the detector yield. The works of development dealing with liquid scintillation counting concern mainly the study of the response of liquid scintillators to low energy electrons as well as their linear absorption coefficients using synchrotron radiation. The research works on pressurized ionization chambers consist of the study of their response to photons and electrons by experimental measurements compared to the simulation of the source-detector system using Monte Carlo codes. Besides, the design of a new type of ionization chamber with variable pressure is presented. This new project was developed to guarantee the precision of the amount of activity injected into the patient within the framework of diagnosis examination

Determination of 131I in milk using a liquid scintillation technique

International Nuclear Information System (INIS)

Palagyi, S.; Markusova, R.

1978-01-01

The method is based on the specific extraction of radioiodine using a liquid anion exchanger and measuring its radioactivity with a toluene based liquid scintillator. Milk proteins are precipitated with trichloroacetic acid and separated by filtration through asbestos. Radioiodine from whey is oxidized to I 2 with NaNO 2 or H 2 O 2 and purified by a benzene-water extraction cycle using sodium sulphite. Finally, the radioiodine is separated and concentrated into toluene solution of a liquid anion exchanger. Before radioactivity counting, the organic phase is decolourized with Na 2 SO 3 using methanol as solubilizer. The method takes about 2.5 hrs without radioactivity counting. The radiochemical yield is higher than 70% and the counting efficiency is 82%. (author)

The development of a single-crystal fiber-array scintillator area detector

International Nuclear Information System (INIS)

Loong, Chun; Vitt, Richard; Sayir, Ali; Sayir, Haluk

2001-01-01

The scientific output of a neutron instrument is directly proportional to the effectiveness of its detector system-coverage of scattering area, pixel resolution, counting efficiency, signal-to-noise ratio, life time and cost. The current neutron scintillator detectors employ mainly 6 Li-doped glass and ZnS, both of which present well-know limitations such as low light output, high gamma sensitivity in the case of 6 Li-glass and optical opacity in the case of ZnS. We aim to develop a position-sensitive, flight-time differentiable, efficient and cost-effective neutron detector system based on single-crystal scintillator fiber-arrays. The laser-heated melt modulation fiber growth technology developed at NASA provides the means to grow high-purity single-crystal fibers or rods of variable diameters (200 μm to 5 mm) and essentially unlimited length. Arrays of such fibers can be tailored to meet the requirements of pixel size, geometric configuration, and coverage area for a detector system. We report a plan in the growth and characterization of scintillators based on lithium silicates and boron aluminates using Ce as activator. (author)

Liquid Scintillation Counting - Packard Triple-Label Calibration

Energy Technology Data Exchange (ETDEWEB)

Torretto, P. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-03-23

The Radiological Measurements Laboratory (RML) maintains and operates nine Packard Liquid Scintillation Counters (LSCs). These counters were obtained through various sources and were generally purchased as 2500, 2700 or 3100 series counters. In 2004/2005 the software and firmware on the counters were upgraded. The counters are now designated as 3100 series counters running the Quantasmart software package. Thus, a single procedure can be used to calibrate and operate the Packard LSCs.

Water quality - Determination of tritium activity concentration - Liquid scintillation counting method (International Standard Publication ISO 9698:1989)

International Nuclear Information System (INIS)

Stefanik, J.

1999-01-01

This International Standard specifies a method for the determination of tritiated water ([ 3 H]H 2 O) activity concentration in water by liquid scintillation counting. The method is applicable to all types of water including seawater with tritium activity concentrations of up to 10 6 Bq/m 3 when using 20 ml counting vials. Below tritium activity concentrations of about 5 x 10 4 Bq/m 3[ 8], a prior enrichment step and/or the measurement of larger sample volumes can significantly improve the accuracy of the determination and lower the limit of detection. Tritium activity concentrations higher than 10 6 Bq/m 3 may be determined after appropriate dilution with distilled water of proven low tritium content. An alternative method for the determination of these higher activities involves increasing the tritium activity concentrations of the internal standard solution. The method is not applicable to the analysis of organically bound tritium; its determination requires an oxidative digestion

Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatory

Science.gov (United States)

Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; Dallier, R.; D'Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; Debatin, J.; del Peral, L.; Deligny, O.; Di Giulio, C.; Di Matteo, A.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; D'Olivo, J. C.; Dorofeev, A.; dos Anjos, R. C.; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Fuster, A.; García, B.; Garcia-Pinto, D.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Glass, H.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A.; LaHurd, D.; Latronico, L.; Lauscher, M.; Lebrun, P.; Legumina, R.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Mockler, D.; Molina-Bueno, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Müller, G.; Muller, M. A.; Müller, S.; Naranjo, I.; Navas, S.; Nellen, L.; Neuser, J.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, H.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollant, R.; Rautenberg, J.; Ravignani, D.; Reinert, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Rogozin, D.; Rosado, J.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanabria Gomez, J. D.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Scarso, C.; Schauer, M.; Scherini, V.; Schieler, H.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Strafella, F.; Suarez, F.; Suarez Durán, M.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Taborda, O. A.; Tapia, A.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Torri, M.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valbuena-Delgado, A.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yang, L.; Yelos, D.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.

2017-03-01

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10 m2 detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), is proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (~2%), show a promising performance for this new system.

Resolving time of scintillation camera-computer system and methods of correction for counting loss, 2

International Nuclear Information System (INIS)

Iinuma, Takeshi; Fukuhisa, Kenjiro; Matsumoto, Toru

1975-01-01

Following the previous work, counting-rate performance of camera-computer systems was investigated for two modes of data acquisition. The first was the ''LIST'' mode in which image data and timing signals were sequentially stored on magnetic disk or tape via a buffer memory. The second was the ''HISTOGRAM'' mode in which image data were stored in a core memory as digital images and then the images were transfered to magnetic disk or tape by the signal of frame timing. Firstly, the counting-rates stored in the buffer memory was measured as a function of display event-rates of the scintillation camera for the two modes. For both modes, stored counting-rated (M) were expressed by the following formula: M=N(1-Ntau) where N was the display event-rates of the camera and tau was the resolving time including analog-to-digital conversion time and memory cycle time. The resolving time for each mode may have been different, but it was about 10 μsec for both modes in our computer system (TOSBAC 3400 model 31). Secondly, the date transfer speed from the buffer memory to the external memory such as magnetic disk or tape was considered for the two modes. For the ''LIST'' mode, the maximum value of stored counting-rates from the camera was expressed in terms of size of the buffer memory, access time and data transfer-rate of the external memory. For the ''HISTOGRAM'' mode, the minimum time of the frame was determined by size of the buffer memory, access time and transfer rate of the external memory. In our system, the maximum value of stored counting-rates were about 17,000 counts/sec. with the buffer size of 2,000 words, and minimum frame time was about 130 msec. with the buffer size of 1024 words. These values agree well with the calculated ones. From the author's present analysis, design of the camera-computer system becomes possible for quantitative dynamic imaging and future improvements are suggested. (author)

Some history of liquid scintillator development at Los Alamos

International Nuclear Information System (INIS)

Ott, D.G.

1979-01-01

The early developments in liquid scintillation counting made at Los Alamos Scientific Laboratory are reviewed. Most of the work was under the direction of F.N. Hayes and included counter development and applications as well as synthesis and chemistry of liquid scintillators

Estimation of low level gross alpha activities in the radioactive effluent using liquid scintillation counting technique

International Nuclear Information System (INIS)

Bhade, Sonali P.D.; Johnson, Bella E.; Singh, Sanjay; Babu, D.A.R.

2012-01-01

A technique has been developed for simultaneous measurement of gross alpha and gross beta activity concentration in low level liquid effluent samples in presence of higher activity concentrations of tritium. For this purpose, alpha beta discriminating Pulse Shape Analysis Liquid Scintillation Counting (LSC) technique was used. Main advantages of this technique are easy sample preparation, rapid measurement and higher sensitivity. The calibration methodology for Quantulus1220 LSC based on PSA technique using 241 Am and 90 Sr/ 90 Y as alpha and beta standards respectively was described in detail. LSC technique was validated by measuring alpha and beta activity concentrations in test samples with known amount of 241 Am and 90 Sr/ 90 Y activities spiked in distilled water. The results obtained by LSC technique were compared with conventional planchet counting methods such as ZnS(Ag) and end window GM detectors. The gross alpha and gross beta activity concentrations in spiked samples, obtained by LSC technique were found to be within ±5% of the reference values. (author)

The reduction of background signal in bismuth germanate scintillators

International Nuclear Information System (INIS)

Lewis, T.A.

1986-07-01

Bismuth germanate (BGO) is one of several new scintillator materials developed in recent years. It has similar energy resolution (6-8%) to sodium iodide (NaI) but it is non-hygroscopic, has a much better Peak-to-Compton ratio and a stopping power about 2.3 times greater than NaI. For counting activated foils it represents an improvement on NaI for high efficiency counting where the resolution of a germanium spectrometer is not required. Two scintillators bought for this purpose were found to have a higher than expected background signal between 500 keV and 2 MeV which was traced to Bi207, an active isotope of bismuth with a 38 year half-life and not listed as occurring naturally. Reference to the manufacturer showed all crystals to be similarly contaminated. It is speculated that this active isotope arises from cosmic proton activation of associated lead in the ore from which the bismuth is extracted. Although not confirmed rigorously it has been shown that bismuth extracted from ore with a low lead content does not contain Bi207. Scintillators have been manufactured from uncontaminated material and reductions in the background signal of more than an order of magnitude have been achieved. This reduction will be of immediate benefit for monitoring nickel foils (fast flux monitors) activated in zero-energy reactors and should also permit the exploitation of other low probability reactions previously not thought to be feasible. (author)

Usage of liquid scintillation counting for detecting the chemiluminescence of cells and its application in medicine

International Nuclear Information System (INIS)

Li Tianxing; Liang Qizhong; Zou Xiaowei; Yang Zhaohen; Huang Yong; Li Huaqiang

1995-01-01

The liquid scintillator counting-chemiluminescence (LSC-CL) of mono-photon radiance is a sensitive, handy and high-autoanalytic technique. Through measuring basic CL, dependent CL and maximum phagocytic CL of polymorphonuclear (PMN), we studied best factor levels of the method with orthogonal design [L 9 (3 4 )]. The results showed the peak forms changed markedly (inter-group P -4 M). PMN-CL in blood was measured during acute attack of the old patients with chronic bronchitis and the children with pneumonia bronchial. It was suggested that PMN phagocytosis decreased. So the dynamic analysis of maximum phagocytic CL would help us with the deep going clinical researches of the mechanisms of anti-inflammation and injuring by the oxygen free radicals

Scintillation counter: photomultiplier tube alignment

International Nuclear Information System (INIS)

Olson, R.E.

1975-01-01

A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into the sample receiving zone. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (auth)

Scintillation counter, maximum gamma aspect

International Nuclear Information System (INIS)

Thumim, A.D.

1975-01-01

A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

Discrimination methods between neutron and gamma rays for boron loaded plastic scintillators

CERN Document Server

Normand, S; Haan, S; Louvel, M

2002-01-01

Boron loaded plastic scintillators exhibit interesting properties for neutron detection in nuclear waste management and especially in investigating the amount of fissile materials when enclosed in waste containers. Combining a high thermal neutron efficiency and a low mean neutron lifetime, they are suitable in neutron multiplicity counting. However, due to their high sensitivity to gamma rays, pulse shape discrimination methods need to be developed in order to optimize the passive neutron assay measurement. From the knowledge of their physical properties, it is possible to separate the three kinds of particles that have interacted in the boron loaded plastic scintillator (gamma, fast neutron and thermal neutron). For this purpose, we have developed and compared the two well known discrimination methods (zero crossing and charge comparison) applied for the first time to boron loaded plastic scintillator. The setup for the zero crossing discrimination method and the charge comparison methods is thoroughly expl...

Express determination of the volume 222Rn activity using the Lucas Type scintillation cells

International Nuclear Information System (INIS)

Muellerova, M.; Holy, K.; Polaskova, A.

2006-01-01

This report deals with the possibility of the accurate determination of the volume radon activity using the Lucas type scintillation chamber before the radioactive equilibrium between the radon and its decay products is achieved. This method allows to obtain data about the volume activity of the sample promptly and also it offers a possibility to apply the detector for measurements more times a day. We developed a method for the determination of the detection efficiency of the scintillation chamber for varied time periods after the chamber was filled up with a sample. The volume radon activity calculated from the count rates in saturated conditions is in a good agreement with the volume radon activity calculated from our derived relation. It was shown that the scintillation chamber can be used for the express determination of the volume radon activity. The time between the individual applications of the scintillation chamber can be compressed maintaining of sufficient accuracy of the determination of the volume radon activity. (authors)

A nonimaging scintillation probe to measure penile hemodynamics.

Science.gov (United States)

Zuckier, L S; Korupolu, G R; Gladshteyn, M; Sattenberg, R; Goldstein, R; Ricciardi, R; Goodwin, P; Melman, A; Blaufox, M D

1995-12-01

We have developed a penile nonimaging scintillation (PNIS) probe consisting of a plastic well-type scintillation crystal interfaced to a portable computer and acquisition board. This report describes the design of the PNIS probe, performance characteristics, mode of usage and illustrative results which demonstrate its capabilities. With the PNIS probe, penile blood-pool studies were performed in nine patients utilizing 3.7 MBq (100 microCi) autologous 99mTc-labeled red blood cells (RBCs). Venous blood standards were assayed to enable conversion of the count rate to volummetric measurements. Washin of peripherally administered 99mTc-RBCs was mathematically analyzed to estimate penile blood volume and cavernosal flow rate in the flaccid state. The rate of change of penile blood volume after intracavernosal vasodilators was used to generate measures of stimulated flow. A major advantage of this device over the gamma-camera is a 3300-fold increase in count rate sensitivity, which allows for markedly improved temporal resolution while significantly reducing the radiopharmaceutical dosage. Additionally, the PNIS probe is portable, economical and is not dependent on operator-defined regions of interest. Count rate sensitivity is relatively constant within the bore, with the exception of the proximal region adjacent to the opening, where geometric efficiency is reduced. The PNIS probe is an effective device for measuring penile activity in radionuclide studies, allowing for acquisition of time-activity curves of the penis during flaccid washin of peripherally labeled red blood cells and after pharmacologic stimulation to induce erection.

Performance of two liquids scintillation and optimization of a Wallac 1411 counter in the tritium quantification in aqueous samples; Desempeno de dos centelleadores liquidos y optimizacion de un contador Wallac 1411 en la cuantificacion de tritio en muestras acuosas

Energy Technology Data Exchange (ETDEWEB)

Contreras de la Cruz, E. de J.; Lopez del Rio, H.; Davila R, J. I.; Mireles G, F.; Pinedo V, J. L., E-mail: hlopezdelrio@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

2014-10-15

The optimization of a liquid scintillation counting Wallac 1411 is presented as well as the performance of the liquids scintillation miscible in water OptiPhase Hi Safe 3 and Last Gold Ab, in the tritium quantification in aqueous samples. The luminescence effect, the quenching, the solution ph and the level of pulse amplitude comparator (Pac) were evaluated in the response of both liquids scintillation in the tritium measurement. The quenching and the luminescence modify the scintillators response; in the first of them the counting efficiency decreases and the minimum detectable activity increases; the second interferes in the tritium quantification in the interest window, but the effect disappears after 4 hours of darkness of the samples. The maximum counting efficiency was of 24% for OptiPhase Hi Safe 3 and 31% for Last Gold Ab, diminishing with the quenching until values of 8 and 11%, respectively. For a counting time of 6 hours and lower quenching, the minimum detectable concentration for OptiPhase Hi Safe 3 was of 13.4 ± 0.2 Bq/L and 9.9 ± 0.1 Bq/L for Last Gold Ab. Both scintillators responded appropriately to sour and basic solutions, being only presented chemiluminescence in Last Gold Ab to ph highly basic. The Pac application that varies between 1 and 256 does not have effect in the tritium measurement until values above 90. (Author)

Digital liquid-scintillation counting and effective pulse-shape discrimination with artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Langrock, Gert; Wiehl, Norbert; Kling, Hans-Otto; Mendel, Matthias; Naehler, Andrea; Tharun, Udo; Eberhardt, Klaus; Trautmann, Norbert; Kratz, Jens Volker [Mainz Univ. (Germany). Inst. fuer Kernchemie; Omtvedt, Jon-Petter [Oslo Univ. (Norway). Dept. of Chemistry; Skarnemark, Gunnar [Chalmers Univ. of Technology, Goeteborg (Sweden)

2015-05-01

A typical problem in low-level liquid scintillation (LS) counting is the identification of α particles in the presence of a high background of β and γ particles. Especially the occurrence of β-β and β-γ pile-ups may prevent the unambiguous identification of an α signal by commonly used analog electronics. In this case, pulse-shape discrimination (PSD) and pile-up rejection (PUR) units show an insufficient performance. This problem was also observed in own earlier experiments on the chemical behaviour of transactinide elements using the liquid-liquid extraction system SISAK in combination with LS counting. α-particle signals from the decay of the transactinides could not be unambiguously assigned. However, the availability of instruments for the digital recording of LS pulses changes the situation and provides possibilities for new approaches in the treatment of LS pulse shapes. In a SISAK experiment performed at PSI, Villigen, a fast transient recorder, a PC card with oscilloscope characteristics and a sampling rate of 1 giga samples s{sup -1} (1 ns per point), was used for the first time to record LS signals. It turned out, that the recorded signals were predominantly α β-β and β-γ pile up, and fission events. This paper describes the subsequent development and use of artificial neural networks (ANN) based on the method of 'back-propagation of errors' to automatically distinguish between different pulse shapes. Such networks can 'learn' pulse shapes and classify hitherto unknown pulses correctly after a learning period. The results show that ANN in combination with fast digital recording of pulse shapes can be a powerful tool in LS spectrometry even at high background count rates.

PPO-ethanol system as wavelength shifter for the Cherenkov counting technique using a liquid scintillation counter

International Nuclear Information System (INIS)

Takiue, M.; Fujii, H.; Ishikawa, H.

1984-01-01

2,5-diphenyloxazole (PPO) has been proposed as a wavelength shifter for Cherenkov counting. Since PPO is not incorporated with water, we have introduced the fluor into water in the form of micelle using a PPO-ethanol system. This technique makes it possible to obtain a high Cherenkov counting efficiency under stable sample conditions, attributed to the proper spectrometric features of the PPO. The 32 P Cherenkov counting efficiency (68.4%) obtained from this technique is 1.62 times as large as that measured with a conventional Cherenkov technique. (orig.)

A comparative study using liquid scintillation counting to determine 63Ni in low and intermediate level radioactive waste

International Nuclear Information System (INIS)

Gautier, Celine; Colin, Christele; Garcia, Cecile

2016-01-01

A comparative study using liquid scintillation counting was performed to measure 63 Ni in low and intermediate level radioactive waste. Three dimethylglyoxime (DMG)-based radiochemical procedures (solvent extraction, precipitation, extraction chromatography) were investigated, the solvent extraction method being considered as the reference method. Theoretical speciation calculations enabled to better understand the chemical reactions involved in the three protocols and to optimize them. In comparison to the method based on DMG precipitation, the method based on extraction chromatography allowed to achieve the best results in one single step in term of recovery yield and accuracy for various samples. (author)

Photon counting detector for the personal radiography inspection system “SIBSCAN”

Energy Technology Data Exchange (ETDEWEB)

Babichev, E.A.; Baru, S.E. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Grigoriev, D.N. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova st. 2, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk 630073 (Russian Federation); Leonov, V.V. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Oleynikov, V.P. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova st. 2, Novosibirsk 630090 (Russian Federation); Porosev, V.V., E-mail: porosev@inp.nsk.su [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova st. 2, Novosibirsk 630090 (Russian Federation); Savinov, G.A. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation)

2017-02-11

X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator – SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5 MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

Photon counting detector for the personal radiography inspection system “SIBSCAN”

International Nuclear Information System (INIS)

Babichev, E.A.; Baru, S.E.; Grigoriev, D.N.; Leonov, V.V.; Oleynikov, V.P.; Porosev, V.V.; Savinov, G.A.

2017-01-01

X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator – SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5 MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

Polyethylene vials for liquid scintillation counters produced by the National Materials Research Institute

International Nuclear Information System (INIS)

Fiser, B.; Lukas, D.

1984-01-01

The properties were tested of polyethylene vials for liquid scintillation counters manufactured by the National Materials Research Institute. Liquid scintillation counter ISOCAP 300 by Nuclear Chicago was used for measuring. For unquenched samples, channel A was set up to 0.5-3.6 keV and channel B to 0.5-18 keV. The scintillation solution was prepared of toluene, 4 g PPO, 0.15 g POPOP per 1 l of toluene. CCl 4 was used as the quenching agent. Radioactive samples were prepared from 20 μl of standard solution of [ 3 H]-toluene with specific activity of 349 Bq/g. All measurements were made using a 7 ml scintillation solution into which radioactivity and possibly quenching agents were added. Potassium-free glass vials by SKLO UNION Teplice and thin-walled polyethylene vials by Nuclear Chicago were used for comparison. The background was measured, as were the time dependences of weight losses of the scintillation solution and carbon tetrachloride from the counting vials, changes in efficiency in channel B with time, changes in SCR with time and changes in the quenching curve with time. (E.S.)

Preparation and calibration by liquid scintillation of a sample of Cl 36. Preparacion y calibracion por centelleo liquido de una muestra de Cl 36

Energy Technology Data Exchange (ETDEWEB)

Grau Malonda, A; Los Arcos, J M; Rodriguez Barquero, L; Suarez, C [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain)

1989-01-01

A procedure to prepare a sample of Clorine 36, as Li{sup 36}Cl, able to be measured by liquid scintillation counting, is described. The sample is chemically stable, with no variation of the quenching parameter up to 4 mg of LiCl per 15 ml of scintillator, keeps constant the counting efficiency for concentration higher than 40 {mu}g of Li{sup 36}Cl in that volume, and shows no deterioration over a 3 weed period. The Li{sup 36}Cl solution has been standarized using the free parameter method with different volumes of toluene, PCS and Instagel, to an uncertainty of 0,3% (Author).

Composition for use in scintillator systems

International Nuclear Information System (INIS)

Tarkkanen, V.

1976-01-01

A liquid scintillation counting composition of the type comprising an aromatic hydrocarbon solvent, an ethoxylated alkyl phenol surfactant, and a scintillation solute, containing a small amount of a substituted ethoxylated carboxylate acid and/or a tertiary amine salt or a quaternary ammonium salt of such acid is described. The free acid reduces chemiluminescence upon the addition of an alkaline sample to the composition, while the tertiary amine or quaternary ammonium salt enhances the water miscibility of the composition

Scintillation neutron detector with dynamic threshold

International Nuclear Information System (INIS)

Kornilov, N.; Massey, T.; Grimes, S.

2014-01-01

Scintillation neutron detectors with hydrogen are a common tool for neutron spectroscopy. They provide good time resolution, neutron-gamma discrimination and high efficiency of neutron counting. The real open problems connected with application of these detectors are in the energy range >10 MeV. There are no standard neutron spectra known with high accuracy for this energy range. Therefore, traditional methods for experimental investigation of the efficiency function fail for these neutrons. The Monte Carlo simulation cannot provide reasonable accuracy due to unknown characteristics of the reactions for charged particle production (p, α and so on, light output, reaction cross-sections). The application of fission chamber with fissile material as a neutron detector did not help to solve the problem. We may avoid many problems if we use the traditional neutron detector with non-traditional data analysis. In this report we give main relations, and demonstrate the method for Cf-source. Experimental detector efficiency is compared with MC simulation. (authors)

A Monte-Carlo code for neutron efficiency calculations for large volume Gd-loaded liquid scintillation detectors

Energy Technology Data Exchange (ETDEWEB)

Trzcinski, A.; Zwieglinski, B. [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Lynen, U. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Pochodzalla, J. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

1998-10-01

This paper reports on a Monte-Carlo program, MSX, developed to evaluate the performance of large-volume, Gd-loaded liquid scintillation detectors used in neutron multiplicity measurements. The results of simulations are presented for the detector intended to count neutrons emitted by the excited target residue in coincidence with the charged products of the projectile fragmentation following relativistic heavy-ion collisions. The latter products could be detected with the ALADIN magnetic spectrometer at GSI-Darmstadt. (orig.) 61 refs.

High Sensitivity Detection of Xe Isotopes Via Beta-Gamma Coincidence Counting

International Nuclear Information System (INIS)

Bowyer, Ted W.; McIntyre, Justin I.; Reeder, Paul L.

1999-01-01

Measurement of xenon fission product isotopes is a key element in the global network being established to monitor the Comprehensive Nuclear-Test-Ban Treaty. Pacific Northwest National Laboratory has developed an automated system for separating Xe from air which includes a beta-gamma counting system for 131mXe, 133mXe, 133Xe, and 135Xe. Betas and conversion electrons are detected in a plastic scintillation cell containing the Xe sample. The counting geometry is nearly 100% for beta and conversion electrons. The resolution in the pulse height spectrum from the plastic scintillator is sufficient to observe distinct peaks for specific conversion electrons. Gamma and X-rays are detected in a NaI(Tl) scintillation detector which surrounds the plastic scintillator sample cell. Two-dimensional pulse height spectra of gamma energy versus beta energy are obtained. Each of the four xenon isotopes has a distinctive signature in the two-dimensional energy array. The details of the counting system, examples of two-dimensional beta-gamma data, and operational experience with this counting system will be described

{sup 222}Rn determination in water and brine samples using liquid scintillation spectrometry

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Thiago C.; Oliveira, Arno H., E-mail: oliveiratco2010@gmail.com [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear; Monteiro, Roberto P.G.; Moreira, Rubens M., E-mail: rpgm@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Liquid scintillation spectrometry (LSC) is the most common technique used for {sup 222}Rn determination in environmental aqueous sample. In this study, the performance of water-miscible (Ultima Gold AB) and immiscible (Optiscint) liquid scintillation cocktails has been compared for different matrices. {sup 241}Am, {sup 90}Sr and {sup 226}Ra standard solutions were used for LSC calibration. {sup 214}Po region was defined as better for both cocktails. Counting efficiency of 76 % and optimum PSA level of 95 for Ultima Gold AB cocktail, and counting efficiency of 82 % and optimum PSA level of 85 for Optiscint cocktail were obtained. Both cocktails showed similar results when applied for {sup 222}Rn activity determination in water and brine samples. However the Optiscint is recommended due to its quenching resistance. Limit of detection of 0.08 and 0.06 Bq l{sup -1} were obtained for water samples using a sample:cocktail ratio of 10:12 mL for Ultima Gold AB and Optiscint cocktails, respectively. Limit of detection of 0.08 and 0.04 Bq l{sup -1} were obtained for brine samples using a sample:cocktail ratio of 8:12 mL for Ultima Gold AB and Optiscint cocktails, respectively. (author)

Measurement of radon emanation of drainage layer media by liquid scintillation counting

International Nuclear Information System (INIS)

Turtiainen, T.

2009-01-01

Slab-on-ground is a typical base floor construction type in Finland. The drainage layer between the slab and soil is a layer of sand, gravel or crushed stone. This layer has a minimum thickness of 200 mm and is sometimes even 600 mm thick, and thus may be a significant contributor to indoor air radon. In order to investigate radon emanation from the drainage layer material, a simple laboratory test was developed. Many organic solvents have high Ostwald coefficients for radon, i.e., the ratio of the volume of gas absorbed to the volume of the absorbing liquid, which enables direct absorption of radon into a liquid scintillation cocktail. Here, we first present equations relating to the processes of gas transfer in emanation measurement by direct absorption into liquid scintillation cocktails. In order to optimize the method for emanation measurement, four liquid scintillation cocktails were assessed for their ability to absorb radon from air. A simple apparatus consisting of a closed glass container holding an open liquid scintillation vial was designed and the diffusion/absorption rate and Ostwald coefficient were determined for a selected cocktail. Finally, a simple test was developed based on this work. (author)

New advanced in alpha spectrometry by liquid scintillation methods

International Nuclear Information System (INIS)

McDowell, W.J.; Case, G.N.

1979-01-01

Although the ability to count alpha particles by liquid scintillation methods has been long recognized, limited use has been made of the method because of problems of high background and alpha energy identification. In recent years some new developments in methods of introducing the alpha-emitting nuclide to the scintillator, in detector construction, and in electronics for processing the energy analog and time analog signals from the detector have allowed significant alleviation of the problems of alpha spectrometry by liquid scintillation. Energy resolutions of 200 to 300 keV full peak width at half maximum and background counts of 99% of all beta plus gamma interference is now possible. Alpha liquid scintillation spectrometry is now suitable for a wide range of applications, from the accurate quantitative determination of relatively large amounts of known nuclides in laboratory-generated samples to the detection and identification of very small, subpicocurie amounts of alpha emitters in environmental-type samples. Suitable nuclide separation procedures, sample preparation methods, and instrument configurations are available for a variety of analyses

Determination of phosphorus-32 in wet-digested plant leaves by Cerenkov counting

International Nuclear Information System (INIS)

Wahid, P.A.; Kamalam, N.V.; Sankar, S.J.

1985-01-01

A method of determination of 32 P activity in leaf samples by Cerenkov counting technique is described. The method involves wet digestion of oven-dried leaves with 1:1 nitric-perchloric acid mixture followed by transferring the digest into a scintillation counting vial with distilled water upto a final volume of 20 mL, and determining the activity in a liquid scintillation system. Reproducible count rates can be obtained if the vials are counted after 4h allowing the silica in the digest to settle. (author)

Dependence of a whole body counting efficiency on body size and composition

International Nuclear Information System (INIS)

Venturini, Luzia; Campos, Vicente P.; Berti, Eduardo A.R.

2001-01-01

An approach is described to evaluate the counting efficiency dependence, on the geometry measurement and on the material density, for whole body measurement. The counting efficiency is evaluated using Monte Carlo Method to simulate the history of the photons, from its emission to its total absorption or escape from the detector. Theoretical calculations of the counting efficiency are presented for two phantoms of the BOMAB family. The phantoms are considered to be filled with water and with a material constituted as described by Snyder et al. (author)

Dependence of a whole body counting efficiency on body size and composition

Energy Technology Data Exchange (ETDEWEB)

Venturini, Luzia; Campos, Vicente P.; Berti, Eduardo A.R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

2001-07-01

An approach is described to evaluate the counting efficiency dependence, on the geometry measurement and on the material density, for whole body measurement. The counting efficiency is evaluated using Monte Carlo Method to simulate the history of the photons, from its emission to its total absorption or escape from the detector. Theoretical calculations of the counting efficiency are presented for two phantoms of the BOMAB family. The phantoms are considered to be filled with water and with a material constituted as described by Snyder et al. (author)

Performance of the latest MPPCs with reduced dark counts and improved photon detection efficiency

International Nuclear Information System (INIS)

Tsujikawa, T.; Funamoto, H.; Kataoka, J.; Fujita, T.; Nishiyama, T.; Kurei, Y.; Sato, K.; Yamamura, K.; Nakamura, S.

2014-01-01

We have tested the performance of two types of the latest Multi-Pixel Photon Counters (MPPCs; measuring 3×3 mm 2 in size) developed by Hamamatsu Photonics K.K. The new S12572-050C is a successor to the S10362-33-050C (i.e., conventional 3×3-mm 2 pixel MPPC of 50 μm pitch), comprises 3600 Geiger mode avalanche photodiodes (APDs), and also features high gain (up to 1.25×10 6 ), a low dark count (up to 10 6 cps), and improved photon detection efficiency (PDE) by up to 30%. The S12572-015C is a new type of fine-pitch (15 μm) MPPC featuring a wide dynamic range and fast timing response. This paper first presents the detailed performance of these latest MPPCs as photon counting devices. It then describes our fabrication of a prototype detector consisting of a MPPC optically coupled with a Ce:GAGG scintillator. We obtained average FWHM energy resolutions of 7.3% (15 μm) and 6.7% (new-50 μm), as compared to 6.9% (old-50 μm) for 662-keV gamma rays from the 137 Cs source, as measured at 20 °C. Moreover, the number of fired pixels for 662-keV gamma rays increased by 30% for the new-50 μm (as compared to the old-50 μm). We confirmed that the low energy threshold improved from 10 keV to 4 keV, when using the latest MPPC device (new-50 μm). We also confirmed that the timing resolution of the new MPPC is 50 ps or even better, as compared to 89 ps of the old MPPC. The results thus confirm that these new types of MPPCs are promising for various applications as scintillation detectors. - Highlights: • We tested the performance of the latest MPPC. • We confirmed that the new MPPC is superior to the old MPPC. • We plan to apply the new MPPC for a next-generation PET and a handy Compton camera

Performance of the latest MPPCs with reduced dark counts and improved photon detection efficiency

Energy Technology Data Exchange (ETDEWEB)

Tsujikawa, T., E-mail: takayuki-t.w@asagi.waseda.jp [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Funamoto, H.; Kataoka, J.; Fujita, T.; Nishiyama, T.; Kurei, Y. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Sato, K.; Yamamura, K.; Nakamura, S. [Solid State Division, Hamamatsu Photonics K. K., 1126-1, Ichino-cho, Hamamatsu, Shizuoka (Japan)

2014-11-21

We have tested the performance of two types of the latest Multi-Pixel Photon Counters (MPPCs; measuring 3×3 mm{sup 2} in size) developed by Hamamatsu Photonics K.K. The new S12572-050C is a successor to the S10362-33-050C (i.e., conventional 3×3-mm{sup 2} pixel MPPC of 50 μm pitch), comprises 3600 Geiger mode avalanche photodiodes (APDs), and also features high gain (up to 1.25×10{sup 6}), a low dark count (up to 10{sup 6} cps), and improved photon detection efficiency (PDE) by up to 30%. The S12572-015C is a new type of fine-pitch (15 μm) MPPC featuring a wide dynamic range and fast timing response. This paper first presents the detailed performance of these latest MPPCs as photon counting devices. It then describes our fabrication of a prototype detector consisting of a MPPC optically coupled with a Ce:GAGG scintillator. We obtained average FWHM energy resolutions of 7.3% (15 μm) and 6.7% (new-50 μm), as compared to 6.9% (old-50 μm) for 662-keV gamma rays from the {sup 137}Cs source, as measured at 20 °C. Moreover, the number of fired pixels for 662-keV gamma rays increased by 30% for the new-50 μm (as compared to the old-50 μm). We confirmed that the low energy threshold improved from 10 keV to 4 keV, when using the latest MPPC device (new-50 μm). We also confirmed that the timing resolution of the new MPPC is 50 ps or even better, as compared to 89 ps of the old MPPC. The results thus confirm that these new types of MPPCs are promising for various applications as scintillation detectors. - Highlights: • We tested the performance of the latest MPPC. • We confirmed that the new MPPC is superior to the old MPPC. • We plan to apply the new MPPC for a next-generation PET and a handy Compton camera.

Composition for use in scintillator systems

International Nuclear Information System (INIS)

Tarkkanen, V.

1976-01-01

Reference is made to compositions for liquid scintillation counting of aqueous radioactive samples. A composition is described that reduces chemiluminescence on the addition of an alkaline material. Many common sample materials, for example body fluids, are inherently alkaline, whilst samples such as animal tissues are often dissolved in alkaline media. Another problem is water miscibility, and the object is to provide a scintillation counting composition that, when mixed with an aqueous sample, produces a single phase low viscosity mixture over a wide range of water contents and temperatures. The composition described includes a major amount of an aromatic hydrocarbon solvent, a minor amount of an ethoxylated alkyl phenol surfactant, a scintillation solute, an amount of a substituted ethoxylated carboxylic acid sufficient to reduce chemiluminescence, and an amount of a tertiary amine salt or a quaternary ammonium salt of the substituted ethoxylated carboxylic acid sufficient to enhance the water miscibility. The hydrocarbon solvent and the surfactant may be pre-treated with a reactive solid metal hydride to remove peroxides, and then subsequently pre-treated with SO 2 . Examples of the use of the composition are given. (U.K)

Efficiency for C-14 measurement in the simulated hydraulic oil waste from a CANDU nuclear power plant as measured on a packard counter

International Nuclear Information System (INIS)

Dianu, Magdalena; Podina, Corneliu; Nita, Valentina

2005-01-01

Full text: The paper mainly contains; - composition and data on liquid scintillation cocktail used; - characterization of radioactive waste - hydraulic oil waste contaminated with C-14; - detection limits; - sample loading; - the values of calculated and measured activities; - efficiency vs sample loading. Samples were counted in a Model 2100 TR Packard TRI-CARB liquid scintillation analyser. Sample preparation is a critical step in obtaining accurate results in scintillation counting. Standard (22 ml) plastic vials were used in these experiments. These vials have the advantage to reduce backgrounds and improve the counting rate. Hydraulic oil sample volumes were added to the vials in 0.5 ml increments from 1 ml to 2 ml. Then the liquid scintillation cocktail was added so that the sample - cocktail volume was 20 ml. Each vial was shaken vigorously for several seconds after each addition to ensure homogeneity and counting. Blank vials were prepared using C-14 - free hydraulic oil samples in the same sample-cocktail proportions. After at least two hours, the samples and blank vials were counted for ten minutes. (authors)

Method for determination of radium-226 in water by liquid scintillation counting

International Nuclear Information System (INIS)

Suomela, J.

1993-07-01

The chemical procedure involves the isolation or radium from the sample solution by co-precipitation with lead sulphate. The precipitate is dissolved in alkaline DTPA. The radium isotopes are separated from other radionuclides by co-precipitation with barium sulphate. The barium/radium precipitate is dissolved in alkaline EDTA, the solution is transfered to a liquid scintillation vial and the organic scintillant is added. After sealing, the sample is left until equilibrium between Ra-226 and Rn-222 is established or until a suitable ingrowth time has elapsed. The alpha activity of Rn-222 and its short-lived daughters, Po-218 and Po-214, are measured by the use of a commercial liquid scintillation counter. By using the following procedure and a low level LSC a lover limit of detection of 2 mBq/sample can be achieved

Measurement of 226Ra in water and 222Rn in water and air by liquid scintillation counting

International Nuclear Information System (INIS)

Schoenhofer, F.

1992-01-01

In the Austrian province of Lower Austria a comprehensive programme for measurement of 222 Rn and 226 Ra in drinking water was conducted. A simple liquid scintillation counting (LSC) method was used which gives a LLD of 30 mBq per litre for 226 Ra without any chemical separation. Results are presented and the health significance is discussed. For 222 Rn in air a commercially available simple charcoal system with LSC was used. The system was tested in a house with elevated radon concentration under normal living conditions. During relatively short 2-day periods a maximum deviation of ± 30% from the monthly mean value was found. The advantages of LSC are that the procedures are very simple and cheap. (author)

Pulse shape discrimination with scintillation detectors

International Nuclear Information System (INIS)

Winyard, R.A.

A quantitative study of pulse shape discrimination with scintillation counters has been undertaken using a crossover timing technique. The scintillators investigated included experimental and commercial liquids and plastics in addition to inorganic phosphors. The versatility of the pulse shape discrimination system has been demonstrated by extending the measurements to investigate phoswiches and liquids loaded with radioactive materials and by its application to the suppression of unwanted backgrounds in delayed coincidence counting for the measurement of nuclear half-lives and isotope identification have been carried out. (author)

Determination of cosmic ray produced radionuclides by means of background radiation counting system, 3

International Nuclear Information System (INIS)

1976-01-01

This is the third report of the progress report series on studies of cosmic ray produced radionuclides by means of low background radiation counting system. In Part I some characteristics of a low beta-gamma coincidence spectrometer are described -- counter system, electronics, background spectra, counting efficiencies -- and studies on radioactive impurities in materials for scientific research are also described. In Part II, suitable solvents for a large scale liquid scintillation counter were examined and best combinations of solvents, solutes and naphthalene are shown. In Part III, miscellaneous topics are reported. (auth.)

Determination of efficiency curves for HPGE detector in different counting geometries

International Nuclear Information System (INIS)

Rodrigues, Josianne L.; Kastner, Geraldo F.; Ferreira, Andrea V.

2011-01-01

This paper presents the first experimental results related to determination of efficiency curves for HPGe detector in different counting geometries. The detector is a GX2520 Canberra belonging to CDTN/CNEN. Efficiency curves for punctual were determined by using a certified set of gamma sources. These curves were determined for three counting geometries. Following that, efficiency curves for non punctual samples were determined by using standard solutions of radionuclides in 500 ml and 1000 ml wash bottle Marinelli

Radiation-induced chemical processes in polystyrene scintillators

International Nuclear Information System (INIS)

Milinchuk, V.K.; Bolbit, N.M.; Klinshpont, E.R.; Tupikov, V.I.; Zhdanov, G.S.; Taraban, S.B.; Shelukhov, I.P.; Smoljanskii, A.S.

1999-01-01

The regularities established for macroradical accumulation and intensity of radioluminescence under γ-irradiation of a polystyrene scintillator prove benzyl macroradicals to be efficient quenchers of the excited scintillator molecules. Dissolved oxygen was determined to have a constant of the quenching rate 100 times lower than that of macroradicals. Oxygen is an efficient antirad because of participating in oxidation reactions and subsequent recombination of macroradicals. The method was developed to obtain a polymeric scintillator with a polystyrene matrix containing a dispersed system of pores and channels. Radiation resistance of such a scintillator is 5-10 times higher than that of standard types

Liquid scintillation cocktails comparison for tritium contamination measurements

International Nuclear Information System (INIS)

Bazzarri, S.; Belloni, P.

1996-01-01

Liquid scintillation counting is one of the most used techniques for the measurements of tritium contamination. Until few years ago a problem related to this kind of measurement was the potential toxicity of the liquid cocktails used to produce the required scintillation. Some new products that guarantee an almost negligible impact on the environment and that are no longer toxic for the operators are now available. Some of this new scintillation cocktail are suitable to be used for tritium measurement. Due to the great benefit from the health point of view of these new materials a test of their scintillation performance has been done at the ENEA centers to select the product having the best characteristics for tritium measurement. (author)

Measuring techniques for environmental sup 3 H, sup 14 C and sup 222 Rn by liquid scintillation counter

Energy Technology Data Exchange (ETDEWEB)

Takata, Shigeru; Saito, Masaaki (Tokyo Metropolitan Isotope Research Center (Japan))

1991-02-01

Measuring techniques for environmental {sup 3}H, {sup 14}C and {sup 222}Rn with a liquid scintillation counter have been studied. {sup 3}H in environmental water was enriched by electrolysis and measured with a low background liquid scintillation counter. By this technique, {sup 3}H concentration of ground water, river water, sea water and rain water at Tokyo was founded to be 0.1 {approx} 2.5 Bq/1. {sup 14}C in taurine and ethyl-alcohol was measured directly liquid scintillation counter. By this {sup 14}C measuring, natural products, contain low level {sup 14}C, were distinguished from synthesised products contain no {sup 14}C. {sup 222}Rn in toluene extracted from environmental water or air was measured by scintillation pulse interval analysis method. By this technique, {sup 222}Rn was able to be measured under very low background counting rate, 0.03cpm, and high efficiency. (author).

Measurement of neutron detection efficiency between 22 and 174 MeV using two different kinds of Pb-scintillating fiber sampling calorimeters

Energy Technology Data Exchange (ETDEWEB)

Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati, INFN (Italy); Bini, C. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Roma (Italy); Corradi, G.; Curceanu, C. [Laboratori Nazionali di Frascati, INFN (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Ferrari, A. [Fondazione CNAO, Milano (Italy); Fiore, S.; Gauzzi, P. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Giovannella, S.; Happacher, F. [Laboratori Nazionali di Frascati, INFN (Italy); Iliescu, M. [Laboratori Nazionali di Frascati, INFN (Italy); IFIN-HH, Bucharest (Romania); Luca, A.; Martini, M. [Laboratori Nazionali di Frascati, INFN (Italy); Miscetti, S., E-mail: stefano.miscetti@lnf.infn.i [Laboratori Nazionali di Frascati, INFN (Italy); Nguyen, F. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Passeri, A. [INFN Sezione di Roma Tre, Roma (Italy)

2010-05-21

We exposed a prototype of the lead-scintillating fiber KLOE calorimeter to neutron beam of 21, 46 and 174 MeV at The Svedberg Laboratory, Uppsala, to study its neutron detection efficiency. This has been found larger than what expected considering the scintillator thickness of the prototype. We show preliminary measurement carried out with a different prototype with a larger lead/fiber ratio, which proves the relevance of passive material to neutron detection efficiency in this kind of calorimeters.

Optimization of 14C liquid scintillation counting of plant and soil lipids to trace short term formation, translocation and degradation of lipids

International Nuclear Information System (INIS)

Wiesenberg, G.L.B.; Gocke, M.; Yakov Kuzyakov

2010-01-01

Two powerful approaches are frequently used to trace incorporation and degradation of plant derived C in soil: 14 C labelling/chasing and analysis of lipid composition. In this study, we coupled these approaches in order to trace short term incorporation of plant derived lipids into rhizosphere and non-rhizosphere soil. Methodological optimization was required and implied 14 C liquid scintillation counting improvement for plant lipid extracts taking into account organic solvents, solvent-to-scintillation cocktail ratio, and amount of lipids. Following method optimization, 14 C data of fatty acids indicated a notable contribution of root derived lipids to rhizosphere and non-rhizosphere soil. Coupling of 14 C labelling/chasing with lipid analysis is a powerful and cheap approach for tracing of root derived C in soil allowing for estimation of C budget, for determination of C formation and translocation within plants and from plant to soil, as well as for identification of short term dynamics of specific compound classes within soil. (author)

Colour quenching corrections on the measurement of 90Sr through Cerenkov counting

International Nuclear Information System (INIS)

Mosqueda, F.; Villa, M.; Vaca, F.; Bolivar, J.P.

2007-01-01

The determination of 90 Sr through the Cerenkov radiation emitted by its descendant 90 Y is a well-known method and firmly established in literature. Nevertheless, in order to obtain an accurate result based on a Cerenkov measurement, the experimental work must be extremely rigorous because the efficiency of Cerenkov counting is especially sensitive to the presence of colour. Any traces of colour in the sample produce a decrease in the number of photons detected in the photomultipliers and, therefore, this might cause a diminution in Cerenkov counting efficiency. It is essential not only to detect the effect of colour quenching in the sample but also to correct the decrease in counting efficiency. For this reason, colour quenching correction curves versus counting efficiency are usually done when measuring through Cerenkov counting. One of the most widely used techniques to evaluate colour quenching in these measurements is the channel ratio method, which consists of the measurement of the shift of the spectrum measuring the ratio of counts in two different windows. The selection of the windows for the application of the corrections might have an influence on the quality of the fitting parameters of the correction curves efficiency versus colour quenching degree and hence on the final 90 Sr result. This work is focused on the calculation of the counting efficiency decrease using the channel ratio method and on obtaining the best fitting correction curve. For this purpose, empirical curves obtained through artificial quenchers have been studied and the results have been tested in real samples. Additionally, given that the Packard Tri-Carb 3170 TR/SL liquid scintillation counter is a novel detector for use in Cerenkov counting, the previous calibration of the Tri-Carb 3170 TR/SL detector, necessary for the measurement of 90 Sr, is included

Experimental procedures for the calibration of scintillation cells used in the determination of radon gas concentrations

International Nuclear Information System (INIS)

Grenier, M; Bigu, J.

1982-02-01

Experimental and analytical procedures are described for the calibration of scintillation cells used for the determination of radon gas concentration. In-house designed and built scintillation cells, used routinely in the monitoring of radon gas in uranium mine underground environments and in the laboratory, were calibrated. The cells had a volume of approximately 158 cm 3 and an α-counting efficiency ranging from 50% to 64%. Calibration factors for the cells were determined. Values ranged approximately from 0.177 cpm/pCiL -1 (4.77 cpm/BqL -1 ) to 0.224 cpm/pCiL -1 (6.05 cpm/BqL -1 ). The calibration facilities at the Elliot Lake Laboratory are briefly described

A time - zero detector based on thin film plastic scintillator

International Nuclear Information System (INIS)

Petrovici, M.; Simion, V.; Pagano, A.; Urso, S.; Geraci, E.

1998-01-01

Thin film scintillator used as a fast time-zero detector exhibits some advantages: fast response, small energy loss of transmitted particles, insensitivity to radiation damage, high efficiency and high counting rate capability. In order to increase the efficiency of the light collection, the scintillating plastic foil is housed in a reflecting body having an ellipsoidal geometry. A concave ellipsoidal mirror has the property that the geometrical foci are optically conjugate points and consequently, all optical path lengths from one focus to the other via a single reflection are equal. With the thin scintillator foil situated at one focal point and the PM's photocathode at the other one, an excellent light collection can be obtained. The principle of detector and the main components are presented. For our purposes we constructed the detector in two variants: glass mirror and polished aluminium mirror. The semi-axes of the ellipsoidal profile are: a 49.8 mm, b = 34.2 mm for the glass mirror and a = 35 mm, b = 26.5 mm for the aluminium mirror, respectively. The diameter of the beam access hole on the both mirrors is 12 mm. The detectors are foreseen to be used at 4π detecting system CHIMERA for experiments with heavy ion beams at intermediate energies delivered by Superconducting Cyclotron from LNS - Catania. Presently, the performance of these detectors are tested using alpha radioactive sources and in-beam measurements. (authors)

Analytical method of Kr-85 determination, using cryogenic concentration and separation and liquid scintillation counting; Desarrollo del metodo de concentracion y se paracion criogenica cromatografica y medida radiactiva por centelleo liquido de Kr-85

Energy Technology Data Exchange (ETDEWEB)

Heras, M C; Perez, M M; Grau, A

1983-07-01

The method used in the Laboratory of the JEN for the determination of Kr-85 levels in gaseous effluents of nuclear power and in the atmosphere is described. Samples of air, collected in metallic cylinders, are introduced into a gas-solid chromatographic separation system which resolves Kr from the other air components. The separated Kr ia dissolved in a toluene based scintillation cocktail, and the Kr-85 content is determined by liquid scintillation counting. (Author)

Cherenkov and scintillation light separation in organic liquid scintillators

Energy Technology Data Exchange (ETDEWEB)

Caravaca, J.; Descamps, F.B.; Land, B.J.; Orebi Gann, G.D. [University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Yeh, M. [Brookhaven National Laboratory, Upton, NY (United States)

2017-12-15

The CHErenkov/Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2 g/L of PPO as a fluor (LAB/PPO). This is the first successful demonstration of Cherenkov light detection from the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 ± 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 ± 3% and 63 ± 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 ± 5% and 38 ± 4. LAB/PPO data is consistent with a rise time of τ{sub r} = 0.72 ± 0.33 ns. (orig.)

Cherenkov and scintillation light separation in organic liquid scintillators

International Nuclear Information System (INIS)

Caravaca, J.; Descamps, F.B.; Land, B.J.; Orebi Gann, G.D.; Yeh, M.

2017-01-01

The CHErenkov/Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2 g/L of PPO as a fluor (LAB/PPO). This is the first successful demonstration of Cherenkov light detection from the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 ± 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 ± 3% and 63 ± 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 ± 5% and 38 ± 4. LAB/PPO data is consistent with a rise time of τ r = 0.72 ± 0.33 ns. (orig.)

Processing of liquid scintillation nuclear spectra for unquenched and quenched sources

International Nuclear Information System (INIS)

Madan, V.K.; Gopalakrishnan, K.R.

1997-01-01

This paper describes a nuclear (beta) spectral analysis method for qualitative and quantitative analysis of radioactivity for use in a liquid scintillation counting system. It is based on computing a spectral index number (SIN) for qualitative analysis of an unquenched sample. For quantitative analysis it was proposed that a complementary nonlinear function be estimated between efficiency and SIN from a standard set of samples. It reduces the computational burden. An unknown sample is analyzed by computing its SIN and that is used to calculate efficiency using the function to facilitate quantitative analysis. A software was developed and verified on real spectra of radioisotopes. The paper presents the method and its application with results. (author). 5 refs

Investigation of Cerenkov counting of environmental strontium-90

International Nuclear Information System (INIS)

Reynolds, S.A.; Eldridge, J.S.

1979-01-01

A typical liquid scintillation counter was evaluated for detection of low levels of 90 Sr-Y. A blank of about 5 cpm and 90 Y efficiency of 42% were obtained for 20-ml samples. The corresponding minimum detectable concentration for a 100-minute count is 0.03 pCi/ml, so that measurement of water samples can readily be made at the maximum permissible concentration for 90 Sr, 0.3 pCi/ml. The efficiency for 90 Sr is less than 0.4%, 1.4% for 137 Cs, and less than 0.04% for gamma-emitting 85 Sr, a useful tracer. Some data for 90 Y efficiencies and blanks are given for other liquid scintillation counters. Chemical treatments are necessary in some cases to concentrate 90 Sr-Y, to remove colored substances which cause quenching, or to eliminate interfering radionuclides. However, the manipulations need not be as elaborate as in conventional radiochemical analysis methods for 90 Sr. Ferric ion (yellow) quenches at the 5 ppM level, but the interference can be eliminated by adding a reducing agent. The Rn daughter 214 Bi, an interfering radionuclide, disappears by decay in 2-3 hours after removal of Rn by sweeping with air or gas. Concentration-separation methods studied have included precipitation and ion exchange

Plastic scintillators with {beta}-diketone Eu complexes for high ionizing radiation detection

Energy Technology Data Exchange (ETDEWEB)

Adadurov, A.F., E-mail: adadurov@isma.kharkov.ua [Institute for Scintillating Materials, NAN of Ukraine, Lenin Avenue 60, 61001 Kharkov (Ukraine); Zhmurin, P.N.; Lebedev, V.N.; Kovalenko, V.N. [Institute for Scintillating Materials, NAN of Ukraine, Lenin Avenue 60, 61001 Kharkov (Ukraine)

2011-10-15

Luminescent and scintillation properties of polystyrene-based plastic scintillators with {beta}-diketone Eu complexes are investigated. A scintillator with dibenzoylmethane Eu complex containing two phenyl groups demonstrates the maximum scintillating efficiency. It is shown that plastic scintillators efficiency is dramatically decreased if {beta}-diketone derivatives contain no phenyl groups as substituents. This fact can be explained by exciplex mechanism of energy transfer from a matrix to Eu complex. - Highlights: > Fluorescent properties of polystyrene scintillators with {beta}-diketone complexes of Eu were studied. > Scintillating efficiency is increased with the number of phenyl groups in Eu complex. > This is related to exciplex mechanism of energy transfer from a polymer matrix to Eu complex.

Alpha liquid-scintillation spectrometry used for the measurement of uranium/thorium-disequilibria in soil samples

International Nuclear Information System (INIS)

Fueeg, B.; Tschachtli, T.; Kraehenbuehl, U.

1997-01-01

For the measurements of low-level radioactivity of natural samples. It is of interest to have a system with high counting efficiency. Alpha liquid-scintillation spectrometry is attractive, because it offers a 4 π geometry. Some chemical separation can be obtained using extractive scintillators. Due to quenching problems for natural samples, additional separation power is needed. A new sample preparation method was developed employing extraction chromatographic resin for measuring 238 U, 234 U, 232 Th, 230 Th, 228 Th and 226 Ra in soil samples, without using any uranium- or thorium-tracer for determining the chemical yields. This method was tested by analyzing the two different reference materials, IAEA-375, soil from Tschernobyl, as well as IAEA SDA-1, a deep-sea sediment with a high calcium content. For all analyzed radionuclides the recoveries were better than 90% with errors (confidence level of 95%) smaller than 5%. The minimal detectable concentration ranges between 0.2 and 0.8 Bq/kg, based on a one gram aliquot of sample and 80'000 seconds counting time. (orig.)

Design, building and evaluation of a neutron detection device based on boron loaded plastic scintillator

International Nuclear Information System (INIS)

Normand, St.

2001-10-01

This work focuses on the study, the characterization and the fabrication of Boron-loaded plastic scintillators. Their use in thermal and fast neutron detection devices is also investigated. Fabrication process, especially boron doping, is explained in the first part of this work. Several FTIR, UV-visible and NMR analysis methods were used in order to characterize the material and to check its structure and stoichiometry. Experiences were done using alpha particles and proton beams to measure the scintillation characteristics. Light emission could therefore be completely determined by the Birks semi-empirical relation. In the second part, the whole detector simulation is undergone: interaction between material and radiation, light generation, paths and signal generation. Neutron simulation by MCNP (Monte Carlo N-Particles) is coupled to a light generation and propagation code developed especially during this work. These simulation tools allow us to optimize the detector geometry for neutron detection and to determine the geometry influence to the photon collection efficiency. Neutron detection efficiency and mean lifetime in this scintillator are also simulated. The close fit obtained between experimental measurements and simulations demonstrate the reliability of the method used. The third part deals with the discrimination methods between neutron and gamma, such as analog (zero crossing) and digital (charge comparison) ones. Their performances were explained and compared. The last part of this work reports on few applications where neutron detection is essential and can be improved with the use of boron loaded plastic scintillators. In particular, the cases of doped scintillation fibers, neutron spectrometry devices and more over neutron multiplicity counting devices are presented. (author)

Radon counting statistics - a Monte Carlo investigation

International Nuclear Information System (INIS)

Scott, A.G.

1996-01-01

Radioactive decay is a Poisson process, and so the Coefficient of Variation (COV) of open-quotes nclose quotes counts of a single nuclide is usually estimated as 1/√n. This is only true if the count duration is much shorter than the half-life of the nuclide. At longer count durations, the COV is smaller than the Poisson estimate. Most radon measurement methods count the alpha decays of 222 Rn, plus the progeny 218 Po and 214 Po, and estimate the 222 Rn activity from the sum of the counts. At long count durations, the chain decay of these nuclides means that every 222 Rn decay must be followed by two other alpha decays. The total number of decays is open-quotes 3Nclose quotes, where N is the number of radon decays, and the true COV of the radon concentration estimate is 1/√(N), √3 larger than the Poisson total count estimate of 1/√3N. Most count periods are comparable to the half lives of the progeny, so the relationship between COV and count time is complex. A Monte-Carlo estimate of the ratio of true COV to Poisson estimate was carried out for a range of count periods from 1 min to 16 h and three common radon measurement methods: liquid scintillation, scintillation cell, and electrostatic precipitation of progeny. The Poisson approximation underestimates COV by less than 20% for count durations of less than 60 min

Response of CsI:Pb Scintillator Crystal to Neutron Radiation

Science.gov (United States)

Costa Pereira, Maria da Conceição; Filho, Tufic Madi; Berretta, José Roberto; Náhuel Cárdenas, José Patrício; Iglesias Rodrigues, Antonio Carlos

2018-01-01

The helium-3 world crisis requires a development of new methods of neutron detection to replace commonly used 3He proportional counters. In the past decades, great effort was made to developed efficient and fast scintillators to detect radiation. The inorganic scintillator may be an alternative. Inorganic scintillators with much higher density should be selected for optimal neutron detection efficiency taking into consideration the relevant reactions leading to light emission. These detectors should, then, be carefully characterized both experimentally and by means of advanced simulation code. Ideally, the detector should have the capability to separate neutron and gamma induced events either by amplitude or through pulse shape differences. As neutron sources also generate gamma radiation, which can interfere with the measurement, it is necessary that the detector be able to discriminate the presence of such radiation. Considerable progress has been achieved to develop new inorganic scintillators, in particular increasing the light output and decreasing the decay time by optimized doping. Crystals may be found to suit neutron detection. In this report, we will present the results of the study of lead doped cesium iodide crystals (CsI:Pb) grown in our laboratory, using the vertical Bridgman technique. The concentration of the lead doping element (Pb) was studied in the range 5x10-4 M to 10-2 M . The crystals grown were subjected to annealing (heat treatment). In this procedure, vacuum of 10-6 mbar and continuous temperature of 350°C, for 24 hours, were employed. In response to neutron radiation, an AmBe source with energy range of 1 MeV to 12 MeV was used. The activity of the AmBe source was 1Ci Am. The fluency was 2.6 x 106 neutrons/second. The operating voltage of the photomultiplier tube was 1700 V; the accumulation time in the counting process was 600 s and 1800 s. The scintillator crystals used were cut with dimensions of 20 mm diameter and 10 mm height.

Colour quenching corrections on the measurement of {sup 90}Sr through Cerenkov counting

Energy Technology Data Exchange (ETDEWEB)

Mosqueda, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21071 Huelva (Spain)], E-mail: fernando.mosqueda@dfa.uhu.es; Villa, M. [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla, Av. Reina Mercedes 4B, E41012 Sevilla (Spain); Vaca, F.; Bolivar, J.P. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21071 Huelva (Spain)

2007-12-05

The determination of {sup 90}Sr through the Cerenkov radiation emitted by its descendant {sup 90}Y is a well-known method and firmly established in literature. Nevertheless, in order to obtain an accurate result based on a Cerenkov measurement, the experimental work must be extremely rigorous because the efficiency of Cerenkov counting is especially sensitive to the presence of colour. Any traces of colour in the sample produce a decrease in the number of photons detected in the photomultipliers and, therefore, this might cause a diminution in Cerenkov counting efficiency. It is essential not only to detect the effect of colour quenching in the sample but also to correct the decrease in counting efficiency. For this reason, colour quenching correction curves versus counting efficiency are usually done when measuring through Cerenkov counting. One of the most widely used techniques to evaluate colour quenching in these measurements is the channel ratio method, which consists of the measurement of the shift of the spectrum measuring the ratio of counts in two different windows. The selection of the windows for the application of the corrections might have an influence on the quality of the fitting parameters of the correction curves efficiency versus colour quenching degree and hence on the final {sup 90}Sr result. This work is focused on the calculation of the counting efficiency decrease using the channel ratio method and on obtaining the best fitting correction curve. For this purpose, empirical curves obtained through artificial quenchers have been studied and the results have been tested in real samples. Additionally, given that the Packard Tri-Carb 3170 TR/SL liquid scintillation counter is a novel detector for use in Cerenkov counting, the previous calibration of the Tri-Carb 3170 TR/SL detector, necessary for the measurement of {sup 90}Sr, is included.

Measurement of Organ Uptake by Whole-Body Counting

International Nuclear Information System (INIS)

Dudley, R.A.

1970-01-01

This paper reviews methods for the measurement of radioactivity in body organs based on whole-body radioactivity measurements. Such measurements can of course only be used to measure radioactivity in a body organ when the radioactivity is exclusively localized in the organ or when the ratio of radioactivity in the organ to that in the whole body is known from other sources of information. They find particular applications, however, when the organ is so widely dispersed throughout the body that more localized measurement is impossible. Examples of situations in which whole-body radioactivity measurements have been used in this way are cited. The more important techniques used for such measurements are described and their respective advantages and disadvantages indicated. The importance of uniformity of counting efficiency with position of source throughout the body is stressed. Simple systems incorporating sodium iodide crystal scintillation detectors are shown to combine satisfactory sensitivity and uniformity of efficiency for clinical measurements of radioactivity in body organs and have the additional advantage that they can be readily adapted for profile scanning. Systems incorporating plastic or liquid scintillation detectors are less convenient in this respect. (author)

Manual calibration of liquid scintillation counter using the channel ratio technique

International Nuclear Information System (INIS)

Moussa, H.M.; Townsend, L.; Miller, L.F.

1999-01-01

The objectives of this activity are to introduce students to liquid scintillation counting and to calibrate the counter using the sample channel ratio technique. This is accomplished by using quenched standards set for 14 C and tritium ( 3 H) to generate a quench correction curve for the scintillation solution. It is a good method for students to gain a detailed understanding of issues important to manual calibration of a liquid scintillation counter, and results can be compared with a built-in automatic method

Plastic scintillators with β-diketone Eu complexes for high ionizing radiation detection

International Nuclear Information System (INIS)

Adadurov, A.F.; Zhmurin, P.N.; Lebedev, V.N.; Kovalenko, V.N.

2011-01-01

Luminescent and scintillation properties of polystyrene-based plastic scintillators with β-diketone Eu complexes are investigated. A scintillator with dibenzoylmethane Eu complex containing two phenyl groups demonstrates the maximum scintillating efficiency. It is shown that plastic scintillators efficiency is dramatically decreased if β-diketone derivatives contain no phenyl groups as substituents. This fact can be explained by exciplex mechanism of energy transfer from a matrix to Eu complex. - Highlights: → Fluorescent properties of polystyrene scintillators with β-diketone complexes of Eu were studied. → Scintillating efficiency is increased with the number of phenyl groups in Eu complex. → This is related to exciplex mechanism of energy transfer from a polymer matrix to Eu complex.

Calculation of the counting efficiency for extended sources

International Nuclear Information System (INIS)

Korun, M.; Vidmar, T.

2002-01-01

A computer program for calculation of efficiency calibration curves for extended samples counted on gamma- and X ray spectrometers is described. The program calculates efficiency calibration curves for homogeneous cylindrical samples placed coaxially with the symmetry axis of the detector. The method of calculation is based on integration over the sample volume of the efficiencies for point sources measured in free space on an equidistant grid of points. The attenuation of photons within the sample is taken into account using the self-attenuation function calculated with a two-dimensional detector model. (author)

The use of energy information in plastic scintillator materia

International Nuclear Information System (INIS)

Ely, J.; Anderson, K.; Bates, D.; Kouzes, R.; Lo Presti, C.; Runkle, R.; Siciliano, E.; Weier, D.

2008-01-01

Plastic scintillator material is often used for gamma-ray detection in many applications due to its relatively good sensitivity and cost-effectiveness compared to other detection materials. However, due to the dominant Compton scattering interaction mechanism, full energy peaks are not observed in plastic scintillator spectra and isotopic identification is impossible. Typically plastic scintillator detectors are solely gross count detectors. In some safeguards and security applications, such as radiation portal monitors for vehicle screening, naturally-occurring radioactive material (NORM) often triggers radiation alarms and results in innocent or nuisance alarms. The limited energy information from plastic scintillator material can be used to discriminate the NORM from targeted materials and reduce the nuisance alarm rate. An overview of the utilization of the energy information from plastic scintillator material will be presented, with emphasis on the detection capabilities and potential limitations for safeguards and security applications. (author)

Eu-activated fluorochlorozirconate glass-ceramic scintillators

International Nuclear Information System (INIS)

Johnson, J. A.; Schweizer, S.; Henke, B.; Chen, G.; Woodford, J.; Newman, P. J.; MacFarlane, D. R.

2006-01-01

Rare-earth-doped fluorochlorozirconate (FCZ) glass-ceramic materials have been developed as scintillators and their properties investigated as a function of dopant level. The paper presents the relative scintillation efficiency in comparison to single-crystal cadmium tungstate, the scintillation intensity as a function of x-ray intensity and x-ray energy, and the spatial resolution (modulation transfer function). Images obtained with the FCZ glass-ceramic scintillator and with cadmium tungstate are also presented. Comparison shows that the image quality obtained using the glass ceramic is close to that from cadmium tungstate. Therefore, the glass-ceramic scintillator could be used as an alternative material for image formation resulting from scintillation. Other inorganic scintillators such as single crystals or polycrystalline films have limitations in resolution or size, but the transparent glass-ceramic can be scaled to any shape or size with excellent resolution

Improved organic scintillation detectors; Possibilites de perfectionnement des detecteurs organiques a scintillations; Usovershenstvovannye organicheskie stsintillyatsionnye detektory; Detectores organicos de centelleo perfeccionados

Energy Technology Data Exchange (ETDEWEB)

Birks, J B [University of Manchester, Manchester (United Kingdom)

1962-04-15

Equations have been derived for the practical scintillation efficiency (photo-electrons/MeV) of organic crystals and solutions in terms of molecular parameters and these have been applied to the more important scintillator systems, for photomultipliers with S11 (glass window) and S13 (quartz window) responses. The results suggest several improvements in current organic scintillation detector practice: the use of binary rather than ternary solutions; the use of quartz rather than glass windows; and the reconsideration of mixed crystal scintillators based on naphthalene. Improvements by factors of 2 or more in the figure of merit (practical efficiency/decay time) for fast-scintillation counting can be obtained. (author) [French] L'auteur a etabli des equations pour determiner le rendement de scintillation (photoelectrons/MeV) de cristaux et solutions organiques, en faisant intervenir des parametres moleculaires. Il a applique ces equations a des appareils a scintillations plus importantes pour determiner la reponse des photomultiplicateurs a fenetre en verre (S11) et a fenetre en quartz (S13). Les resultats obtenus ont fait apparaitre la possibilite d'ameliorer, a plusieurs egards, les detecteurs organiques a scintillations du type courant, par exemple en remplacant les solutions ternaires par des solutions binaires, les fenetres en verre par des fenetres en quartz, ou en reexaminant les possibilites offertes par les scintillateurs a cristaux mixtes a base de naphtalene. L'introduction de ces perfectionnements conduirait a une amelioration, du simple au double ou plus, du facteur de qualite (efficacite/temps de decroissance) des dispositifs de comptage a scintillations. (author) [Spanish] Se han establecido ecuaciones que permiten calcular el rendimiento practico de centelleo (fotoelectrones/MeV) de los cristales y soluciones organicos en funcion de parametros moleculares; estas ecuaciones han sido aplicadas a los sistemas de centelleo mas importantes, para

Plastic scintillation dosimetry: Optimal selection of scintillating fibers and scintillators

International Nuclear Information System (INIS)

Archambault, Louis; Arsenault, Jean; Gingras, Luc; Sam Beddar, A.; Roy, Rene; Beaulieu, Luc

2005-01-01

Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter

Using Cherenkov Counting For Fast Determination of 90Sr/90Y Activity in Milk

International Nuclear Information System (INIS)

Tsroya, S.; Dolgin, B.; German, U.; Pelled, O.; Alfassi, Z. B.

2014-01-01

90Sr is one of the main long-lived fission products, and it is transferred into human body primarily by food, with milk being a substantial contributor. Due to its biochemical similarity to calcium, most strontium is efficiently incorporated into bone tissues. 90Sr is characterized by a long physical half life (28.8 y) and decays by beta particles with an Emax of 0.546 MeV to 90Y. This daughter isotope has a half life of 64 h and decays into 90Zr by beta particles with an Emax of 2.284 MeV. The milk components produce a high turbidity and light attenuation, causing a significant decrease of the counting efficiency in liquid scintillation counting (LSC) systems, mostly used for beta emitters detection. Most methods proposed in the past are time-consuming, as they are based on several stages of chemical and physical treatments, including precipitation, ashing, ion exchange and extraction (Wikins et al., 1984, Porter et al, 1961, Kimura et al., 1979). When measuring 90Sr/90Y activity by Cherenkov counting, most of the Cherenkov radiation is produced by 90Y (about 98.6%), due to the much higher energy of its beta particles relative to these from 90Sr. The counting efficiency varies strongly with color quenching, at a greater extent than in standard liquid scintillation counting (L'Annunziata, 2012), and therefore the quench correction is critical. The ‘‘external source area ratio’’ (ESAR) quench correction method was applied to measure 90Sr/90Y activities in aqueous samples with a wide range of quenching levels (Tsroya et al., 2009). This method was proved to be superior to all other quench correction methods (Tsroya et al., 2012) and is applicable also for determination of 90Sr/90Y in human urine (Tsroya et al., 2013). In the present work the applicability of the ESAR method to measurement of 90Sr/90Y activities in milk and some of its products was investigated

Studying the properties of the new class of organic scintillators-salicylic acid derivatives

International Nuclear Information System (INIS)

Mandzhukov, I.G.; Mandzhukova, B.V.; Bonchev, Ts.V.; Lazarova, G.I.

1981-01-01

Li, Na, K, Mg, Ca, Sr, Ba, La, Cd, Al, Sn, NH 4 salicylates are synthesized. Their relative scintillation efficiency during irradiation with α-particles of 5.156 MeV energy (sup(239)Pu) is determined. Scintillation efficiency of salicylates has been evaluated by comparing amplitude of scintillation pulse from salicylate with pulse amplitude from anthracene and other classical scintillators. Amplitude analysis has been conducted by standard methods. The analysis of the results obtained shows that sodium salicylate has the highest relative scintillation efficiency comparable with naphthalene efficiency. Salicylates of alkali Li and K metals as well as Ca and Cd salicylates have high relative scintillation efficiency. It is concluded that the investigated salicylates can be used for detection of (n, α), (n, p) and other reactions accompanying neutron capture not only during their reactions but by measuring activity induced in the scintillator [ru

Characterization of some modern scintillators recommended for use on large fusion facilities in γ-ray spectroscopy and tomographic measurements of γ-emission profiles

Directory of Open Access Journals (Sweden)

Sibczynski Pawel

2017-09-01

Full Text Available LaBr3:Ce,CeBr3 and GAGG:Ce scintillators were investigated and the determined characteristics were compared with those obtained for the well-known and widely used CsI:Tl and NaI:Tl crystals. All the detectors were of the same size of 10 × 10 × 5 mm3. The aim of this test study was to single out scintillation detectors most suitable for γ-ray spectrometry and γ-ray emission radial profile measurements in high-temperature plasma experiments. Decay time, energy resolution, non-proportionality and full energy peak detection efficiency ere measured for γ-ray energies up to 1770 keV. Due to their good energy resolution, short decay time and high detection efficiency for MeV gamma rays, LaBr3:Ce and CeBr3 scintillators are proposed as the best candidates for use especially under conditions of high count rates, which are expected in the forthcoming DT experiments.

Counting neutrons with a commercial S-CMOS camera

Science.gov (United States)

Patrick, Van Esch; Paolo, Mutti; Emilio, Ruiz-Martinez; Estefania, Abad Garcia; Marita, Mosconi; Jon, Ortega

2018-01-01

It is possible to detect individual flashes from thermal neutron impacts in a ZnS scintillator using a CMOS camera looking at the scintillator screen, and off line image processing. Some preliminary results indicated that the efficiency of recognition could be improved by optimizing the light collection and the image processing. We will report on this ongoing work which is a result from the collaboration between ESS Bilbao and the ILL. The main progress to be reported is situated on the level of the on-line treatment of the imaging data. If this technology is to work on a genuine scientific instrument, it is necessary that all the processing happens on line, to avoid the accumulation of large amounts of image data to be analyzed off line. An FPGA-based real-time full-deca mode VME-compatible CameraLink board has been developed at the SCI of the ILL, which is able to manage the data flow from the camera and convert it in a reasonable "neutron impact" data flow like from a usual neutron counting detector. The main challenge of the endeavor is the optical light collection from the scintillator. While the light yield of a ZnS scintillator is a priori rather important, the amount of light collected with a photographic objective is small. Different scintillators and different light collection techniques have been experimented with and results will be shown for different setups improving upon the light recuperation on the camera sensor. Improvements on the algorithm side will also be presented. The algorithms have to be at the same time efficient in their recognition of neutron signals, in their rejection of noise signals (internal and external to the camera) but also have to be simple enough to be easily implemented in the FPGA. The path from the idea of detecting individual neutron impacts with a CMOS camera to a practical working instrument detector is challenging, and in this paper we will give an overview of the part of the road that has already been walked.

Counting neutrons with a commercial S-CMOS camera

Directory of Open Access Journals (Sweden)

Patrick Van Esch

2018-01-01

Full Text Available It is possible to detect individual flashes from thermal neutron impacts in a ZnS scintillator using a CMOS camera looking at the scintillator screen, and off line image processing. Some preliminary results indicated that the efficiency of recognition could be improved by optimizing the light collection and the image processing. We will report on this ongoing work which is a result from the collaboration between ESS Bilbao and the ILL. The main progress to be reported is situated on the level of the on-line treatment of the imaging data. If this technology is to work on a genuine scientific instrument, it is necessary that all the processing happens on line, to avoid the accumulation of large amounts of image data to be analyzed off line. An FPGA-based real-time full-deca mode VME-compatible CameraLink board has been developed at the SCI of the ILL, which is able to manage the data flow from the camera and convert it in a reasonable “neutron impact” data flow like from a usual neutron counting detector. The main challenge of the endeavor is the optical light collection from the scintillator. While the light yield of a ZnS scintillator is a priori rather important, the amount of light collected with a photographic objective is small. Different scintillators and different light collection techniques have been experimented with and results will be shown for different setups improving upon the light recuperation on the camera sensor. Improvements on the algorithm side will also be presented. The algorithms have to be at the same time efficient in their recognition of neutron signals, in their rejection of noise signals (internal and external to the camera but also have to be simple enough to be easily implemented in the FPGA. The path from the idea of detecting individual neutron impacts with a CMOS camera to a practical working instrument detector is challenging, and in this paper we will give an overview of the part of the road that has

Evaluation of misplaced event count rate using a scintillation camera

International Nuclear Information System (INIS)

Yanagimoto, Shin-ichi; Tomomitsu, Tatsushi; Muranaka, Akira

1985-01-01

Misplaced event count rates were evaluated using an acryl scatter body of various thickness and a gamma camera. The count rate in the region of interest (ROI) within the camera view field, which was thought to represent part of the misplaced event count rate, increased as the thickness of the scatter body was increased to 5 cm, followed by a steep decline in the count rate. On the other hand, the ratio of the count rate in the ROI to the total count rate continuously increased as the thickness of the scatter body was increased. As the thickness of the scatter body was increased, the count rates increased, and the increments of increase were greater in the lower energy region of the photopeak than in the higher energy region. In ranges energy other than the photopeak, the influence of the scatter body on the count rate in the ROI was the greatest at 76 keV, which was the lowest energy we examined. (author)

Two-dimensional diced scintillator array for innovative, fine-resolution gamma camera

International Nuclear Information System (INIS)

Fujita, T.; Kataoka, J.; Nishiyama, T.; Ohsuka, S.; Nakamura, S.; Yamamoto, S.

2014-01-01

We are developing a technique to fabricate fine spatial resolution (FWHM<0.5mm) and cost-effective photon counting detectors, by using silicon photomultipliers (SiPMs) coupled with a finely pixelated scintillator plate. Unlike traditional X-ray imagers that use a micro-columnar CsI(Tl) plate, we can pixelate various scintillation crystal plates more than 1 mm thick, and easily develop large-area, fine-pitch scintillator arrays with high precision. Coupling a fine pitch scintillator array with a SiPM array results in a compact, fast-response detector that is ideal for X-ray, gamma-ray, and charged particle detection as used in autoradiography, gamma cameras, and photon counting CTs. As the first step, we fabricated a 2-D, cerium-doped Gd 3 Al 2 Ga 3 O 12 (Ce:GAGG) scintillator array of 0.25 mm pitch, by using a dicing saw to cut micro-grooves 50μm wide into a 1.0 mm thick Ce:GAGG plate. The scintillator plate is optically coupled with a 3.0×3.0mm pixel 4×4 SiPM array and read-out via the resistive charge-division network. Even when using this simple system as a gamma camera, we obtained excellent spatial resolution of 0.48 mm (FWHM) for 122 keV gamma-rays. We will present our plans to further improve the signal-to-noise ratio in the image, and also discuss a variety of possible applications in the near future

A gamma scintillation spectrometer

Energy Technology Data Exchange (ETDEWEB)

Symbalisty, S

1952-07-01

A scintillation type gamma ray spectrometer employing coincidence counting, designed and built at the Physics Department of the University of Western Ontario is described. The spectrometer is composed of two anthracene and photomultiplier radiation detectors, two pulse analyzing channels, a coincidence stage, three scalers and a high voltage stabilized supply. A preliminary experiment to test the operation of the spectrometer was performed and the results of this test are presented. (author)

Characterization and development of an active scintillating target for nuclear reaction studies on actinides

Energy Technology Data Exchange (ETDEWEB)

Belier, Gilbert, E-mail: gilbert.belier@cea.fr [CEA, DAM, DIF, DPTA, Centre du Grand Rue, 91297 Arpajon (France); Aupiais, Jean; Varignon, Cyril; Vayre, Sylvain [CEA, DAM, DIF, DPTA, Centre du Grand Rue, 91297 Arpajon (France)

2012-02-01

This article presents the development of a new kind of active actinide target, based on organic liquid scintillators containing the dissolved isotope. Amongst many advantages one can mention the very high detection efficiency, the Pulse Shape Discrimination capability, the fast response allowing high count rates and good time resolution and the ease of fabrication. The response of this target to fission fragments has been studied. The discrimination of alpha, fission and proton recoil events is demonstrated. The alpha decay and fission detection efficiencies are simulated and compared to measurements. Finally the use of such a target in the context of fast neutron induced reactions is discussed.

Characterization and development of an active scintillating target for nuclear reaction studies on actinides

International Nuclear Information System (INIS)

Belier, Gilbert; Aupiais, Jean; Varignon, Cyril; Vayre, Sylvain

2012-01-01

This article presents the development of a new kind of active actinide target, based on organic liquid scintillators containing the dissolved isotope. Amongst many advantages one can mention the very high detection efficiency, the Pulse Shape Discrimination capability, the fast response allowing high count rates and good time resolution and the ease of fabrication. The response of this target to fission fragments has been studied. The discrimination of alpha, fission and proton recoil events is demonstrated. The alpha decay and fission detection efficiencies are simulated and compared to measurements. Finally the use of such a target in the context of fast neutron induced reactions is discussed.

A gamma-ray discriminating neutron scintillator

International Nuclear Information System (INIS)

Eschbach, P.A.; Miller, S.D.; Cole, M.C.

1994-01-01

A neutron scintillator has been developed at Pacific Northwest Laboratory which responds directly to as little as 10 mrem/hour dose equivalent rate fast neutron fields. The scintillator is composed of CaF 2 :Eu or of NaI grains within a silicone rubber or polystyrene matrix, respectively. Neutrons colliding with the plastic matrix provide knockon protons, which in turn deposit energy within the grains of phosphor to produce pulses of light. Neutron interactions are discriminated from gamma-ray events on the basis of pulse height. Unlike NE-213 liquid scintillators, this solid scintillator requires no pulseshape discrimination and therefore requires less hardware. Neutron events are anywhere from two to three times larger than the gamma-ray exposures are compared to 0.7 MeV gamma-ray exposures. The CaF 2 :Eu/silicone rubber scintillator is nearly optically transparent, and can be made into a very sizable detector (4 cm x 1.5 cm) without degrading pulse height. This CaF 2 :Eu scintillator has been observed to have an absolute efficiency of 0.1% when exposed to 5-MeV accelerator-generated neutrons (where the absolute efficiency is the ratio of observed neutron events divided by the number of fast neutrons striking the detector)

Automatic quench compensation for liquid scintillation counting system

International Nuclear Information System (INIS)

Nather, R.E.

1978-01-01

A method of automatic quench compensation is provided, where a reference measure of quench is taken on a sample prior to taking a sample count. The measure of quench is then compared with a reference voltage source which has been established to vary in proportion to the variation of the measure of quench with the level of a system parameter required to restore at least one isotope spectral energy endpoint substantially to a selected counting window discriminator level in order to determine the amount of adjustment of the system parameter required to restore the endpoint. This is followed by the appropriate adjustment of the system parameter required to restore the relative position of the discriminator windows and the sample spectrum and is followed in turn by taking a sample count

A new plastic scintillator with large Stokes shift

International Nuclear Information System (INIS)

Destruel, P.; Taufer, M.

1989-01-01

We have developed a new plastic scintillator with the novel characteristic of highly localized light emission; scintillation and wavelength shifting take place within a few tens of micrometers of the primary ionization. The new scintillator consists of a scintillating polymer base [polyvinyl toluene (PVT) or polystyrene (PS)] doped with a single wavelength shifter, 1-phenyl-3-mesityl-2-pyrazoline (PMP), which has an exceptionally large Stokes shift and therefore a comparatively small self-absorption of its emitted light. In other characteristics (e.g. scintillation efficiency and decay time) the performance of the new scintillator is similar to a good quality commercial plastic scintillator such as NE110. (orig.)

Improvements to well scintillation counters

International Nuclear Information System (INIS)

Farukhi, M.R.; Mataraza, G.A.; Wimer, O.D.

1977-01-01

This invention relates to the field of ionising radiation detection. It concerns in particular scintillation detectors of the type that is commonly used in conjunction with a photomultiplier tube and that is used for monitoring radiation, for instance in the clinical measurements of isotopes. This invention enables well scintillation counters to be made, characterised by a high efficiency in measuring the thindown rate of radio-pharmaceutical solutions and to resolve the distribution of energy emanating from the radioactive source. It particularly consists in improving the uniformity of the luminous efficiency, the quality of the resolution and the efficiency whilst improving the reception of light [fr

Evaluation of the photon transmission efficiency of light guides used in scintillation detectors using LightTools code

International Nuclear Information System (INIS)

Park, Hye Min; Joo, Koan Sik; Kim, Jeong Ho; Kim, Dong Sung; Park, Ki Hyun; Park, Chan Jong; Han, Woo Jin

2016-01-01

To optimize the photon transmission efficiency of light guides used in scintillation detectors, LightTools code, which can construct and track light, was used to analyze photon transmission effectiveness with respect to light guides thickness. This analysis was carried out using the commercial light guide, N-BK 7 Optical Glass by SCHOTT, as a model for this study. The luminous exitance characteristic of the LYSO scintillator was used to analyze the photon transmission effectiveness according to the thickness of the light guide. The results of the simulations showed the effectiveness of the photon transmission according to the thickness of the light guide, which was found to be distributed from 13.38% to 33.57%. In addition, the photon transmission efficiency was found to be the highest for light guides of 4 mm of thickness and a receiving angle of 49 .deg. . Through such simulations, it is confirmed that photon transmission efficiency depends on light guide thickness and subsequent changes in the internal angle of reflection. The aim is to produce an actual light guide based on these results and to evaluate its performance

On the use of single large-area photodiodes in scintillation counters

International Nuclear Information System (INIS)

Morrell, C.

1989-12-01

The compilation of this review was originally intended to assess the possibility of using photodiode-based scintillation counters in fluorescence EXAFS (or FLEXAFS) systems as a low-cost alternative to photomultiplier-based counters. The X-ray energies encountered in FLEXAFS experiments range from a few keV to a few tens of keV, and detectors are required to have some energy resolution and/or high count-rate capability in order to optimize the quality of data collected. The results presented in the reviewed literature imply strongly that photodiodes do not compete successfully with photomultipliers in scintillation counting systems for X-ray energies below the order of 100keV, at least at the present stage of photodiode technology. Nevertheless it is likely that there are other applications requiring X-ray detectors for which a photodiode-based scintillation counter may be perfectly adequate, and it is therefore felt that such a review is still useful. In addition, large-area single photodiodes have much to offer as X-ray detectors in their own right, and several of the considerations regarding their use in scintillation counters are highly relevant to this application. (author)

Method for determining the irradiation dose deposited in a scintillator by ionising radiation and associated device - WO 2013060745 A1

International Nuclear Information System (INIS)

2013-01-01

The invention relates to a method for determining an irradiation dose deposited in a scintillator (5) by ionising radiation, said method comprising the steps of: irradiating the scintillator (5) for a pre-determined time; detecting an instant at which the scintillator (5) is excited, using a first photodetector (11); subsequently, detecting an instant at which a scintillation photon is received, using a second photodetector (14) operating in single photon counting mode; identifying each sequence formed by the detection of an excitation instant by the first photodetector (11) and the detection of a reception instant by the second photodetector (14) at a coincidence event; counting the number of coincidence events; and obtaining the irradiation dose deposited during the irradiation time as a function of the number of coincidence events counted and a pre-determined proportionality factor. (authors)

Time resolution research in liquid scintillating detection

International Nuclear Information System (INIS)

He Hongkun; Shi Haoshan

2006-01-01

The signal processing design method is introduced into liquid scintillating detection system design. By analyzing the signal of liquid scintillating detection, improving time resolution is propitious to upgrade efficiency of detecting. The scheme of realization and satisfactory experiment data is demonstrated. Besides other types of liquid scintillating detection is the same, just using more high speed data signal processing techniques and elements. (authors)

Preparation of manganese salts of carboxylic acids labelled with ''54Mn and comparison with ''54 MnCl{sub 2} in liquid scintillation counting; Preparacion de sales manganosas de acidos alifaticos monocarboxilicos marcados con ''54 MnCl{sub 2} en medidas por centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Arcos Merino, J. M. los; Grau Malonda, A.

1992-07-01

Procedures for liquid scintillation sample preparation of manganese dimethylbutirate, decanoate and palmitate, labelled with 54 Mn are described. their quenching effect, spectral evolution and counting stability along several weeks are analysed in liquid scintillation measurements with Toluene. HISafe II. PCS, instagel. Dioxane-naphtalene and Toluene-alcohol. For comparison, Inorganic 54 MnCl-2 samples are also studied, resulting in acceptable counting stability but showing greater quenching and signs of little spectral degradation against the organic samples. (Author)

Ionic liquids as solvents for liquid scintillation technology. Čerenkov counting with 1-Butyl-3-Methylimidazolium Chloride

International Nuclear Information System (INIS)

Mirenda, Martín; Rodrigues, Darío; Arenillas, Pablo; Gutkowski, Karin

2014-01-01

We report the detection of the Čerenkov luminescence after the incorporation of a few droplets of a physiological solution of 2-deoxi-2( 18 F)fluorine-D-glucose into the ionic liquid 1-Butyl-3-Methylimidazolium Chloride (BmimCl). The phenomenon is attributed to the β + particles having energy above the threshold energy value for the Čerenkov radiation in this medium. The presence of another type of radiation that could eventually cause coincidences in the photodetectors was safely discarded. We show that this property serves to determine the activity of a 18 F solution by means of the novel TDCR–Čerenkov technique. The results were compared with those obtained from the classic TDCR scintillation method using a commercial scintillation cocktail. The activity values obtained from both methods were found to be virtually identical within the experimental uncertainties. The fact that high energy β particles in BmimCl generates Čerenkov photons makes this ionic liquid a promising compound for future research in detection and quantification of ionizing radiation, and it provides a potential alternative for applications in nuclear technology. - Highlights: • Čerenkov luminescence was detected when 18 F was dissolved in 1-Butyl-3-Methylimidazolium Chloride (BmimCl) ionic liquid. • The presence of another type of radiation that could eventually cause coincidences in the photodetectors was safely discarded. • Čerenkov luminescence serves to determine the activity of a 18 F solution by means of TDCR–Čerenkov technique. • Some advantages of the use of BmimCl as solvent for Čerenkov counting were listed

Theory and application of Cerenkov counting

Energy Technology Data Exchange (ETDEWEB)

Ross, H.H.

1976-01-01

The production of Cherenkov radiation by charged particles moving through a transparent medium (the Cherenkov generator) is a strictly physical process that is virtually independent of the chemistry of the medium. Thus, it is possible to calculate easily all of the important parameters of the Cherenkov process such as excitation threshold, emission intensity, spectral distribution, directional characteristics, and time response. The results of many of these physical effects are unknown in conventional liquid scintillation spectroscopy and, therefore, many unique assay techniques have been developed as a result of their consideration. This paper discusses the theoretical basis of the Cherenkov process, explores the unusual characteristics of the phenomenon, and demonstrates how these unusual characteristics can be used to develop equally unusual counting methodologies. Particular emphasis is directed toward an analysis of published data (obtained with conventional liquid scintillation instrumentation) that would be difficult or impossible to obtain with other counting techniques. Also discussed is a new type of sample vial that uses an isolated waveshifting system. The device was specifically designed for Cherenkov counting.

Fabrication and a Study on the Tapered Scintillator Radiation Sensors

International Nuclear Information System (INIS)

Kim, Gye Hong

2003-02-01

Optical fibers have been investigated for their uses as sensor materials in various nuclear applications. Comprehensive overviews of their potential usages in nuclear environments can be found in the literatures. Optical fibers with doped scintillating elements in the core have drawn special interests as nuclear radiation detectors. The two important functions of a scintillating optical fiber, as a radiation detector, are scintillator (light emitter) and light transmitter. When radiation interacts with the core material, scintillation occurs and resultant lights are transmitted through the fiber to an opto-electronic device such as a photomultiplier tube. Optical fiber sensors have several advantages as compared to other sensors of conventional material. Since they do not require electric power in the sensor part, they are less susceptible to trouble in harsh environments such as underground or underwater. At relatively low cost a multi-point distributed radiation monitoring system could be made using the fiber sensors. Furthermore, unlike the conventional scintillating counters they are not influenced by any magnetic field surrounding them. This study has been conducted to investigate the feasibility of using scintillating optical fibers for the detection of gamma rays emitted by 137 Cs. Several types of gamma-ray sensors have been constructed by packing different numbers of fibers into aluminum tubes, and tested to detect the 137 Cs gamma ray. During the study it has been found that a tapered fibers might be more efficient to collect the lights produced inside the sensor and transfer them into the transmitting fiber. In order to investigate the effectiveness of the tapered fiber, tapered plastic scintillators, composed of polystyrene with minute amount of dPOPOP and PPO or bPBD, have been fabricated and tested for the detection of gamma rays from 1.0, 1.5, 3.0 and 5.0 μCi 137 Cs sources. The pulse height spectra and the relationship between the radioactivity and

Liquid scintillator mixable with water

International Nuclear Information System (INIS)

Benson, R.H.

1976-01-01

A liquid scintillator mixable with water is described consisting of an aromatic solvent (xylene), a scintillation material and an ethoxylated alkyl phenol (as surface-active substance). So far such kinds of system have not given good measurements on counting samples with high water content. Due to the invention's composition one gets good results even with counting samples having a water content of over 30% if the alkyl substituent of the alkyl phenol contains 7, 10, 11, 13, 14, 15 or 16 C atoms and the ratio n/x of the number n of C atoms of the alkyl substituents to the average number x of the ethoxy groups of the ethoxylated alkyl phenols lie between 0.83 and 1.67. The following alkyl phenols are mentioned: heptyl phenol (n/x between 0.83 and 1.08), decyl phenol (n/x between 0.90 and 1.17), hendecyl phenol (n/x between 0.93 and 1.22), tridecyl phenol (n/x between 0.97 and 1.34), tetradecyl phenol (n/x between 1.08 and 1.55), pentadecyl phenol (n/x between 1.15 and 1.67), hexadecyl phenol (n/x between 1.33 and 1.51). (UWI) [de

Thallium bromide photodetectors for scintillation detection

CERN Document Server

Hitomi, K; Shoji, T; Hiratate, Y; Ishibashi, H; Ishii, M

2000-01-01

A wide bandgap compound semiconductor, TlBr, has been investigated as a blue sensitive photodetector material for scintillation detection. The TlBr photodetectors have been fabricated from the TlBr crystals grown by the TMZ method using materials purified by many pass zone refining. The performance of the photodetectors has been evaluated by measuring their leakage current, quantum efficiency, spatial uniformity, direct X-ray detection and scintillation detection characteristics. The photodetectors have shown high quantum efficiency for the blue wavelength region and high spatial uniformity for their optical response. In addition, good direct X-ray detection characteristics with an energy resolution of 4.5 keV FWHM for 22 keV X-rays from a sup 1 sup 0 sup 9 Cd radioactive source have been obtained. Detection of blue scintillation from GSO and LSO scintillators irradiated with a sup 2 sup 2 Na radioactive source has been done successfully by using the photodetectors at room temperature. A clear full-energy pea...

The development of a high-resolution scintillating fiber tracker with silicon photomultiplier readout

International Nuclear Information System (INIS)

Roper Yearwood, Gregorio

2013-01-01

In this work I present the design and test results for a novel, modular tracking detector from scintillating fibers which are read out by silicon photomultiplier (SiPM) arrays. The detector modules consist of 0.25 mm thin scintillating fibers which are closely packed in five-layer ribbons. Two ribbons are fixed to both sides of a carbon-fiber composite structure. Custom made SiPM arrays with a photo-detection efficiency of about 50% read out the fibers. Several 860 mm long and 32 mm wide tracker modules were tested in a secondary 12 GeV/c beam at the PS facilities, CERN in November of 2009. During this test a spatial resolution better than 0.05 mm at an average light yield of about 20 photons for a minimum ionizing particle was determined. This work details the characterization of scintillating fibers and silicon photomultipliers of different make and model. It gives an overview of the production of scintillating fiber modules. The behavior of detector modules during the test-beam is analyzed in detail and different options for the front-end electronics are compared. Furthermore, the implementation of the proposed tracking detector from scintillating fibers within the scope of the PERDaix experiment is discussed. The PERDaix detector is a permanent magnet spectrometer with a weight of 40 kg. It consists of 8 tracking detector layers from scintillating fibers, a time-of-flight detector from plastic scintillator bars with silicon photomultiplier readout and a transition radiation detector from an irregular fleece radiator and Xe/CO 2 filled proportional counting tubes. The PERDaix detector was launched with a helium balloon within the scope of the ''Balloon-Experiments for University Students'' (BEXUS) program from Kiruna, Sweden in November 2010. For a few hours PERDaix reached an altitude of 33 km and measured cosmic rays. In May 2011, the PERDaix detector was characterized during a test-beam at the PS-facilities at CERN. This work introduces methods for event

Synthesis of plastic scintillation microspheres: Evaluation of scintillators

International Nuclear Information System (INIS)

Santiago, L.M.; Bagán, H.; Tarancón, A.; Garcia, J.F.

2013-01-01

The use of plastic scintillation microspheres (PSm) appear to be an alternative to liquid scintillation for the quantification of alpha and beta emitters because it does not generate mixed wastes after the measurement (organic and radioactive). In addition to routine radionuclide determinations, PSm can be used for further applications, e.g. for usage in a continuous monitoring equipment, for measurements of samples with a high salt concentration and for an extractive scintillation support which permits the separation, pre-concentration and measurement of the radionuclides without additional steps of elution and sample preparation. However, only a few manufacturers provide PSm, and the low number of regular suppliers reduces its availability and restricts the compositions and sizes available. In this article, a synthesis method based on the extraction/evaporation methodology has been developed and successfully used for the synthesis of plastic scintillation microspheres. Seven different compositions of plastic scintillation microspheres have been synthesised; PSm1 with polystyrene, PSm2 with 2,5-Diphenyloxazol(PPO), PSm3 with p-terphenyl (pT), PSm4 with PPO and 1,4-bis(5-phenyloxazol-2-yl) (POPOP), PSm5 pT and (1,4-bis [2-methylstyryl] benzene) (Bis-MSB), PSm6 with PPO, POPOP and naphthalene and PSm7 with pT, Bis-MSB and naphthalene. The synthesised plastic scintillation microspheres have been characterised in terms of their morphology, detection capabilities and alpha/beta separation capacity. The microspheres had a median diameter of approximately 130 μm. Maximum detection efficiency values were obtained for the PSm4 composition as follows 1.18% for 3 H, 51.2% for 14 C, 180.6% for 90 Sr/ 90 Y and 76.7% for 241 Am. Values of the SQP(E) parameter were approximately 790 for PSm4 and PSm5. These values show that the synthesised PSm exhibit good scintillation properties and that the spectra are at channel numbers higher than in commercial PSm. Finally, the addition

Surface preparation and coupling in plastic scintillator dosimetry

International Nuclear Information System (INIS)

Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frederic; Beddar, A. Sam; Beaulieu, Luc

2006-01-01

One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity

Waveshifters and Scintillators for Ionizing Radiation Detection

International Nuclear Information System (INIS)

Baumgaugh, B.; Bishop, J.; Karmgard, D.; Marchant, J.; McKenna, M.; Ruchti, R.; Vigneault, M.; Hernandez, L.; Hurlbut, C.

2007-01-01

Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments

Measurement of 103mRh produced by the 103Rh(γ,γ')103mRh reaction with liquid scintillation counting

International Nuclear Information System (INIS)

Sekine, T.; Yoshihara, Kenji; Pavlicsek, I.; Lakosi, L.; Veres, A.

1989-01-01

A liquid scintillation counting technique was applied to measure the isotope 103m Rh (half life = 56.12 min) which is difficult to detect because its γ-ray is of low energy and low emission probability. Tris-(2,4-pentanedionato)rhodium(III) (Rh(acac) 3 ) was irradiated with bremsstrahlung of accelerated 3.2 MeV electrons by LINAC. The method has given a reliable calibration curve for the determination of 103m Rh radioactivity below Rh(acac) 3 concentrations of 2 mM. The integrated cross section of 103 Rh(γ,γ') 103m Rh determined by this method was found to be 6.8±3.4 μb MeV at 3.2 MeV. (author) 8 refs.; 5 figs

Assessment of applicability of portable HPGe detector with in situ object counting system based on performance evaluation of thyroid radiobioassays

Energy Technology Data Exchange (ETDEWEB)

Park, Min Seok; Kwon, Tae Eun; Pak, Min Jung; Park, Se Young; Ha, Wi Ho; Jin, Young Woo [National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2017-06-15

Different cases exist in the measurement of thyroid radiobioassays owing to the individual characteristics of the subjects, especially the potential variation in the counting efficiency. An In situ Object Counting System (ISOCS) was developed to perform an efficiency calibration based on the Monte Carlo calculation, as an alternative to conventional calibration methods. The purpose of this study is to evaluate the applicability of ISOCS to thyroid radiobioassays by comparison with a conventional thyroid monitoring system. The efficiency calibration of a portable high-purity germanium (HPGe) detector was performed using ISOCS software. In contrast, the conventional efficiency calibration, which needed a radioactive material, was applied to a scintillator-based thyroid monitor. Four radioiodine samples that contained 125I and 131I in both aqueous solution and gel forms were measured to evaluate radioactivity in the thyroid. ANSI/HPS N13.30 performance criteria, which included the relative bias, relative precision, and root-mean-squared error, were applied to evaluate the performance of the measurement system. The portable HPGe detector could measure both radioiodines with ISOCS but the thyroid monitor could not measure 125I because of the limited energy resolution of the NaI(Tl) scintillator. The 131I results from both detectors agreed to within 5% with the certified results. Moreover, the 125I results from the portable HPGe detector agreed to within 10% with the certified results. All measurement results complied with the ANSI/HPS N13.30 performance criteria. The results of the intercomparison program indicated the feasibility of applying ISOCS software to direct thyroid radiobioassays. The portable HPGe detector with ISOCS software can provide the convenience of efficiency calibration and higher energy resolution for identifying photopeaks, compared with a conventional thyroid monitor with a NaI(Tl) scintillator. The application of ISOCS software in a radiation

Current trends in scintillator detectors and materials

International Nuclear Information System (INIS)

Moses, W.W.

2002-01-01

The last decade has seen a renaissance in inorganic scintillator development for gamma ray detection. Lead tungstate (PbWO 4 ) has been developed for high-energy physics experiments, and possesses exceptionally high density and radiation hardness, albeit with low luminous efficiency. Lutetium orthosilicate or LSO (Lu 2 SiO 5 :Ce) possesses a unique combination of high luminous efficiency, high density, and reasonably short decay time, and is now incorporated in commercial positron emission tomography cameras. There have been advances in understanding the fundamental mechanisms that limit energy resolution, and several recently discovered materials (such as LaBr 3 :Ce) possess energy resolution that approaches that of direct solid state detectors. Finally, there are indications that a neglected class of scintillator materials that exhibit near band-edge fluorescence could provide scintillators with sub-nanosecond decay times and high luminescent efficiency

Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

Science.gov (United States)

Bok, Jan; Schauer, Petr

2014-01-01

In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF. © 2013 Wiley Periodicals, Inc.

Improving the counting efficiency in time-correlated single photon counting experiments by dead-time optimization

Energy Technology Data Exchange (ETDEWEB)

Peronio, P.; Acconcia, G.; Rech, I.; Ghioni, M. [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

2015-11-15

Time-Correlated Single Photon Counting (TCSPC) has been long recognized as the most sensitive method for fluorescence lifetime measurements, but often requiring “long” data acquisition times. This drawback is related to the limited counting capability of the TCSPC technique, due to pile-up and counting loss effects. In recent years, multi-module TCSPC systems have been introduced to overcome this issue. Splitting the light into several detectors connected to independent TCSPC modules proportionally increases the counting capability. Of course, multi-module operation also increases the system cost and can cause space and power supply problems. In this paper, we propose an alternative approach based on a new detector and processing electronics designed to reduce the overall system dead time, thus enabling efficient photon collection at high excitation rate. We present a fast active quenching circuit for single-photon avalanche diodes which features a minimum dead time of 12.4 ns. We also introduce a new Time-to-Amplitude Converter (TAC) able to attain extra-short dead time thanks to the combination of a scalable array of monolithically integrated TACs and a sequential router. The fast TAC (F-TAC) makes it possible to operate the system towards the upper limit of detector count rate capability (∼80 Mcps) with reduced pile-up losses, addressing one of the historic criticisms of TCSPC. Preliminary measurements on the F-TAC are presented and discussed.

Advanced Large Area Plastic Scintillator Project (ALPS): Final Report

International Nuclear Information System (INIS)

Jordan, David V.; Reeder, Paul L.; Todd, Lindsay C.; Warren, Glen A.; McCormick, Kathleen R.; Stephens, Daniel L.; Geelhood, Bruce D.; Alzheimer, James M.; Crowell, Shannon L.; Sliger, William A.

2008-01-01

The advanced Large-Area Plastic Scintillator (ALPS) Project at Pacific Northwest National Laboratory investigated possible technological avenues for substantially advancing the state-of-the-art in gamma-ray detection via large-area plastic scintillators. The three predominant themes of these investigations comprised the following: * Maximizing light collection efficiency from a single large-area sheet of plastic scintillator, and optimizing hardware event trigger definition to retain detection efficiency while exploiting the power of coincidence to suppress single-PMT 'dark current' background; * Utilizing anti-Compton vetoing and supplementary spectral information from a co-located secondary, or 'Back' detector, to both (1) minimize Compton background in the low-energy portion of the 'Front' scintillator's pulse-height spectrum, and (2) sharpen the statistical accuracy of the front detector's low-energy response prediction as implemented in suitable energy-windowing algorithms; and * Investigating alternative materials to enhance the intrinsic gamma-ray detection efficiency of plastic-based sensors

Background characterization in a liquid scintillation spectrometer; Caracterizacion del fondo de un espectrometro de centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Los Arcos, J.M.; Jimenez de Mingo, A.

1995-07-01

An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0 - 20 KeV, 0 - 800 KeV and 0 - 2 MeV, for volume between 2 and 20 mi of three commercial scintillators, Hisafe II, Ultima-Gold and Instagel, and quenching degree in the interval equivalent to 50% - 3% tritium efficiency. This procedure was tested with standard samples of 3H, and led to average discrepancies less than 10% for activity {>=}0,6 Bq, against conventional methods for which the discrepancies are twice on average. (Author) 10 refs.

The efficient neutron-gamma pulse shape discrimination with small active volume scintillation detector

International Nuclear Information System (INIS)

Phan Van Chuan; Nguyen Duc Hoa; Nguyen Xuan Hai; Nguyen Ngoc Anh; Tuong Thi Thu Huong; Nguyen Nhi Dien; Pham Dinh Khang

2016-01-01

A small detector with EJ-301 liquid scintillation was manufactured for the study on the neutron-gamma pulse shape discrimination. In this research, four algorithms, including Threshold crossing time (TCT), Pulse gradient analysis (PGA), Charge comparison method (CCM), and Correlation pattern recognition (CPR) were developed and compared in terms of their discrimination effectiveness between neutrons and gamma rays. The figures of merits (FOMs) obtained for 100 ÷ 2000 keVee (keV energy electron equivalent) neutron energy range show the charge comparison method was the most efficient of the four algorithms. (author)

Heterogeneous counting on filter support media

International Nuclear Information System (INIS)

Long, E.; Kohler, V.; Kelly, M.J.

1976-01-01

Many investigators in the biomedical research area have used filter paper as the support for radioactive samples. This means that a heterogeneous counting of sample sometimes results. The count rate of a sample on a filter will be affected by positioning, degree of dryness, sample application procedure, the type of filter, and the type of cocktail used. Positioning of the filter (up or down) in the counting vial can cause a variation of 35% or more when counting tritiated samples on filter paper. Samples of varying degrees of dryness when added to the counting cocktail can cause nonreproducible counts if handled improperly. Count rates starting at 2400 CPM initially can become 10,000 CPM in 24 hours for 3 H-DNA (deoxyribonucleic acid) samples dried on standard cellulose acetate membrane filters. Data on cellulose nitrate filters show a similar trend. Sample application procedures in which the sample is applied to the filter in a small spot or on a large amount of the surface area can cause nonreproducible or very low counting rates. A tritiated DNA sample, when applied topically, gives a count rate of 4,000 CPM. When the sample is spread over the whole filter, 13,400 CPM are obtained with a much better coefficient of variation (5% versus 20%). Adding protein carrier (bovine serum albumin-BSA) to the sample to trap more of the tritiated DNA on the filter during the filtration process causes a serious beta absorption problem. Count rates which are one-fourth the count rate applied to the filter are obtained on calibrated runs. Many of the problems encountered can be alleviated by a proper choice of filter and the use of a liquid scintillation cocktail which dissolves the filter. Filter-Solv has been used to dissolve cellulose nitrate filters and filters which are a combination of cellulose nitrate and cellulose acetate. Count rates obtained for these dissolved samples are very reproducible and highly efficient

Glass scintillator pair for compensation neutron logging

International Nuclear Information System (INIS)

Ji Changsong; Li Xuezhi; Yiu Guangduo

1985-01-01

Glass scintillator pair types ST 1604 and ST 1605 for compensation of neutron logging is developed. The neutron sensitive material used is multistick lithium glass scintillators 3 and 4 mm in diameter respectively. Thermoneutron detection efficiencies are 50-60% and 100% respectively. The detection efficiency for 60 Co γ ray is lower than 0.3%. The type ST 1604 and ST 1605 may also be used as high sensitive neutron detectors in an intensive γ ray field

Development of NaI(Tl) scintillating films for imaging soft x-rays

International Nuclear Information System (INIS)

Shepherd, J.A.

1993-01-01

Thin film NaI(Tl) scintillators, of areas of up to 130 cm 2 , have been fabricated and characterized for use on soft x-ray imaging photomultiplier tubes. Relevant parameters of photon-counting imaging detectors are defined and used to predict the performance of several materials, including CsI(Na), CsI(Tl), CaF 2 (Eu), Lu 2 (SiO 4 )O:Ce, and NaI(Tl), as thin film scintillators on fiber optic substrates. Also, x-ray imaging methodologies are compared. The NaI(Tl) films were vapor-deposited onto quartz and fiber optic substrates using a powder flash deposition technique. When compared to single crystal NaI(Tl), the films were found to have equally high light yield but lower energy resolution. Light yield optimization was studied in detail including the effects of substrate temperature, activator concentration in the evaporant, and boat temperature. Spatial resolution as well as parallax errors are discussed and measured for film thicknesses up to 61 μm. A technique is described that can substantially increase the light collection of high index films on fiber optic disks. The light collection was improved by 20% by coating the disk with potassium silicate before the NaI(Tl) deposition. Large area films, up to 130 cm 2 , had a spatial uniformity of response within ±1.5% for count rate and ±3.5% for light yield, and their spatial resolution exceeded 16.6 lp mm -1 when deposited onto fiber optic substrates. The 8-keV x-ray detection efficiency of the microchannel plate imaging photomultiplier tube coupled to a NaI(Tl) film scintillator is predicted to be 88%. Other uses for the films are also described

Computation of full energy peak efficiency for nuclear power plant radioactive plume using remote scintillation gamma-ray spectrometry.

Science.gov (United States)

Grozdov, D S; Kolotov, V P; Lavrukhin, Yu E

2016-04-01

A method of full energy peak efficiency estimation in the space around scintillation detector, including the presence of a collimator, has been developed. It is based on a mathematical convolution of the experimental results with the following data extrapolation. The efficiency data showed the average uncertainty less than 10%. Software to calculate integral efficiency for nuclear power plant plume was elaborated. The paper also provides results of nuclear power plant plume height estimation by analysis of the spectral data. Copyright © 2016 Elsevier Ltd. All rights reserved.

Advanced Large Area Plastic Scintillator Project (ALPS): Final Report

Energy Technology Data Exchange (ETDEWEB)

Jordan, David V.; Reeder, Paul L.; Todd, Lindsay C.; Warren, Glen A.; McCormick, Kathleen R.; Stephens, Daniel L.; Geelhood, Bruce D.; Alzheimer, James M.; Crowell, Shannon L.; Sliger, William A.

2008-02-05

The advanced Large-Area Plastic Scintillator (ALPS) Project at Pacific Northwest National Laboratory investigated possible technological avenues for substantially advancing the state-of-the-art in gamma-ray detection via large-area plastic scintillators. The three predominant themes of these investigations comprised the following: * Maximizing light collection efficiency from a single large-area sheet of plastic scintillator, and optimizing hardware event trigger definition to retain detection efficiency while exploiting the power of coincidence to suppress single-PMT "dark current" background; * Utilizing anti-Compton vetoing and supplementary spectral information from a co-located secondary, or "Back" detector, to both (1) minimize Compton background in the low-energy portion of the "Front" scintillator's pulse-height spectrum, and (2) sharpen the statistical accuracy of the front detector's low-energy response prediction as impelmented in suitable energy-windowing algorithms; and * Investigating alternative materials to enhance the intrinsic gamma-ray detection efficiency of plastic-based sensors.

Method validation and verification in liquid scintillation counting using the long-term uncertainty method (LTUM) on two decades of proficiency test data

International Nuclear Information System (INIS)

Verrezen, F.; Vasile, M.; Loots, H.; Bruggeman, M.

2017-01-01

Results from proficiency tests gathered over the past two decades by the laboratory for low level radioactivity measurements for liquid scintillation counting of 3 H (184 results) and 14 C (74 results) are used to verify the validated measurement methods used by the laboratory, in particular the estimated uncertainty budget of the method and its reproducibility and stability. A linear regression approach is used for the analysis of the results, described in the literature as the long term uncertainty in measurement method. The present study clearly indicates the advantages of using proficiency test results in identifying possible constant or proportional bias effects as well as the possibility to compare the laboratory performance with the performance of peer laboratories. (author)

Validation of Analysis Method of pesticides in fresh tomatoes by Gas Chromatography associated to a liquid scintillation counting

International Nuclear Information System (INIS)

Dhib, Ahlem

2011-01-01

Pesticides are nowadays considered as toxic for human health. The maximum residues levels (MRL) in foodstuff are more and more strict. Therefore, selective analytical techniques are necessary for their identification and their quantification. The aim of this study is to set up a multi residue method for the determination of pesticides in tomatoes by gas chromatography with μECD detector (GC/μECD) associated to liquid scintillation counting. A global analytical protocol consisting of a QuECHERS version of the extraction step followed by purification step of the resulting extract on a polymeric sorbent was set up. The 14 C-chloropyrifos used as an internal standard proved excellent to control the different steps needed for the sample preparation. The method optimized is specific, selective with a recovery averaged more than 70 pour cent, repetitive and reproducible. Although some others criteria need to be checked regarding validation before its use in routine analysis, the potential of the method has been demonstrated.

Neutron diffraction measurements at the INES diffractometer using a neutron radiative capture based counting technique

Energy Technology Data Exchange (ETDEWEB)

Festa, G. [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Pietropaolo, A., E-mail: antonino.pietropaolo@roma2.infn.it [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Grazzi, F.; Barzagli, E. [CNR-ISC Firenze (Italy); Scherillo, A. [CNR-ISC Firenze (Italy); ISIS facility Rutherford Appleton Laboratory (United Kingdom); Schooneveld, E.M. [ISIS facility Rutherford Appleton Laboratory (United Kingdom)

2011-10-21

The global shortage of {sup 3}He gas is an issue to be addressed in neutron detection. In the context of the research and development activity related to the replacement of {sup 3}He for neutron counting systems, neutron diffraction measurements performed on the INES beam line at the ISIS pulsed spallation neutron source are presented. For these measurements two different neutron counting devices have been used: a 20 bar pressure squashed {sup 3}He tube and a Yttrium-Aluminum-Perovskite scintillation detector. The scintillation detector was coupled to a cadmium sheet that registers the prompt radiative capture gamma rays generated by the (n,{gamma}) nuclear reactions occurring in cadmium. The assessment of the scintillator based counting system was done by performing a Rietveld refinement analysis on the diffraction pattern from an ancient Japanese blade and comparing the results with those obtained by a {sup 3}He tube placed at the same angular position. The results obtained demonstrate the considerable potential of the proposed counting approach based on the radiative capture gamma rays at spallation neutron sources.

Positron imaging system with improved count rate and tomographic capability

International Nuclear Information System (INIS)

Muehllehner, G.; Buchin, M.P.

1980-01-01

Improvements to a positron camera imaging system are described. A pair of Angear-type scintillation cameras serve as the detectors, each camera being positioned on opposite sides of the organ of interest. Pulse shaping circuits reduce the pulse duration below 900 nanoseconds and the integration time below 500 noneseconds, improving the count rate capability and the counting statistics of the system and thus the image quality and processing speed. The invention also provides means for rotating the opposed camera heads about an axis which passes through the organ of interest. The cameras do not use collimators, and are capable of accepting radiation travelling in planes not perpendicular to the scintillation crystals. (LL)

Isocount scintillation scanner with preset statistical data reliability

International Nuclear Information System (INIS)

Ikebe, J.; Yamaguchi, H.; Nawa, O.A.

1975-01-01

A scintillation detector scans an object such as a live body along horizontal straight scanning lines in such a manner that the scintillation detector is stopped at a scanning point during the time interval T required for counting a predetermined number of N pulses. The rate R/sub N/ = N/T is then calculated and the output signal pulses the number of which represents the rate R or the corresponding output signal is used as the recording signal for forming the scintigram. In contrast to the usual scanner, the isocount scanner scans an object stepwise in order to gather data with statistically uniform reliability

Low-level flow counting of liquid chromatography column eluates

International Nuclear Information System (INIS)

Harding, N.G.L.; Farid, Y.; Stewart, M.J.

1982-01-01

The principal parameters which determine the operation of a high-resolution, high-sensitivity radioactive flow monitor are described: a) Sample preparation to ensure adequate recovery of radiolabelled sample, metabolites and internal standard. b) The instrument background count rate, when no sample or radiolabel is present in the flow cell, is a function of shielding and a reduction in noise obtained with a coincidence time below one microsecond. c) The minimum detectable amount of label depends upon the machine background, HPLC eluent and scintillator flow, whether or not packed flow cells are used, flow cell geometry, and the scintillator used. d) Three types of flow cell have been designed to cover the majority of HPLC and isotope applications. e) The performance of solid and liquid scintillators. It is shown that an instrument has been designed taking account of these parameters. The resulting design satisfies present high sensitivity counting requirements and maintains the resolution of current HPLC procedures when detection is by simultaneous flow radioassay and by optical methods. (orig.)

Shock-resistant scintillation detector

International Nuclear Information System (INIS)

Novak, W.P.

1979-01-01

A unique scintillation detector unit is disclosed which employs a special light transfer and reflector means that encases and protects the scintillator crystal against high g forces. The light transfer means comprises a flexible silicon rubber optical material bonded between the crystal and the optical window and having an axial thickness sufficient to allow the scintillator to move axially inside the container under high g forces without destroying the bonds. The reflector means comprises a soft elastic silicone rubber sleeve having a multiplicity of closely arranged tapered protrusions radiating toward and engaging the periphery of the scintillator crystal to cushion shocks effectively and having a reflective material, such as aluminum oxide powder, in the spaces between the protrusions. The reflector means provides improved shock absorption because of the uniform support and cushioning action of the protrusions and also provides the detector with high efficiency. The silicon rubber composition is specially compounded to include a large amount of aluminum oxide which enables the rubber to function effectively as a light reflector

Automated high performance liquid chromatography and liquid scintillation counting determination of pesticide mixture octanol/water partition rates

International Nuclear Information System (INIS)

Moody, R.P.; Carroll, J.M.; Kresta, A.M.

1987-01-01

Two novel methods are reported for measuring octanol/water partition rates of pesticides. A liquid scintillation counting (LSC) method was developed for automated monitoring of 14 C-labeled pesticides partitioning in biphasic water/octanol cocktail systems with limited success. A high performance liquid chromatography (HPLC) method was developed for automated partition rate monitoring of several constituents in a pesticide mixture, simultaneously. The mean log Kow +/- SD determined from triplicate experimental runs were for: 2,4-D-DMA (2,4-dichlorophenoxyacetic acid dimethylamine), 0.65 +/- .17; Deet (N,N-diethyl-m-toluamide), 2.02 +/- .01; Guthion (O,O-dimethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate), 2.43 +/- .03; Methyl-Parathion (O,O-dimethyl-O-(p-nitrophenyl) phosphorothioate), 2.68 +/- .05; and Fenitrothion (O,O-dimethyl O-(4-nitro-m-tolyl) phosphorothioate), 3.16 +/- .03. A strong positive linear correlation (r = .9979) was obtained between log Kow and log k' (log Kow = 2.35 (log k') + 0.63). The advantages that this automated procedure has in comparison with the standard manual shake-flask procedure are discussed

Applications of commercial liquid scintillation counters to radon-222 and radium-226 analyses

International Nuclear Information System (INIS)

Gesell, T.F.; Prichard, H.M.; Haygood, J.R.

1978-01-01

The ubiquitous commerical liquid scintillation counter offers automatic sample processing, automatic data recording and the prospect of multiple users. With these features in mind we have explored a number of applications of liquid scintillation counters to environmental and health physics problems. One application, the analysis of radon in water has been described elsewhere and is only briefly reviewed. A method for measuring radon in air, two methods for measuring radium in water, and a technique for leak testing radium needles have also been investigated. An ordinary glass scintillation vial is readily converted into a miniature scintillation flask by coating the inside surface with a thin layer in ZnS:Ag phosphor. The lower limit detection is high, about 2 pCi/1 for a 1 hour count, but these flasks have proved to be useful in situations where a larger number of samples must be taken in environments with relatively high levels of radon. One technique for the detection of radium in water uses liquid-liquid extraction to concentrate radon into an organic scintillation fluid, the other involves passing the water sample through an ion exchange resin and then sealing the resin and scintillation fluid in a vial. Both techniques offer the prospect of easy and inexpensive analyses with limits of detection at or below 0.5 pCi/1. Radium needles can be leak tested by placing them in vials containing toluene for a few minutes, adding fluor to the toluene and counting. Preliminary data regarding these several methods are given

Modifications of micro-pulling-down method for the growth of selected Li-containing crystals for neutron scintillator and VUV scintillation crystals

Science.gov (United States)

Pejchal, J.; Fujimoto, Y.; Chani, V.; Yanagida, T.; Yokota, Y.; Yoshikawa, A.; Nikl, M.; Beitlerova, A.

2012-12-01

To develop new and efficient neutron scintillator, Ti-doped LiAlO2 single crystal was grown by micro-pulling-down method. The X-ray excited radioluminescence spectra and neutron light yield were measured. Positive effect of Mg codoping on the overall scintillation efficiency was found. The BaLu2F8 single crystal was grown by micro-pulling-down method using low temperature gradient at growth interface and applying quenching immediately after growth process.

Design of Fluorescent Compounds for Scintillation Detection

Energy Technology Data Exchange (ETDEWEB)

Pla-Dalmau, Anna [Northern Illinois U.

1990-01-01

Plastic scintillation detectors for high energy physics applications require the development of new fluorescent compounds to meet the demands set by the future generation of particle accelerators such as the Superconducting Supercollider (SSe). Plastic scintillators are commonly based on a polymer matrix doped with two fluorescent compounds: the primary dopant and the wavelength shifter. Their main characteristics are fast response time and high quantum efficiency. The exposure to larger radiation doses and demands for larger light output questions their survivability in the future experiments. A new type of plastic scintillator - intrinsic scintillator - has been suggested. It uses a single dopant as primary and wavelength shifter, and should be less susceptible to radiation damage....

Optimization of liquid scintillation measurements applied to smears and aqueous samples collected in industrial environments

Directory of Open Access Journals (Sweden)

Arnaud Chapon

Full Text Available Search for low-energy β contaminations in industrial environments requires using Liquid Scintillation Counting. This indirect measurement method supposes a fine control from sampling to measurement itself. Thus, in this paper, we focus on the definition of a measurement method, as generic as possible, for both smears and aqueous samples’ characterization. That includes choice of consumables, sampling methods, optimization of counting parameters and definition of energy windows, using the maximization of a Figure of Merit. Detection limits are then calculated considering these optimized parameters. For this purpose, we used PerkinElmer Tri-Carb counters. Nevertheless, except those relative to some parameters specific to PerkinElmer, most of the results presented here can be extended to other counters. Keywords: Liquid Scintillation Counting (LSC, PerkinElmer, Tri-Carb, Smear, Swipe

A comparison between the measurements of Kr-85 in environmental samples by liquid scintillation and proportional counters

International Nuclear Information System (INIS)

Heras Iniquez, M.C.; Perez Garcia, M.M.

1983-01-01

The most used methods for the measurement of Kr-81 beta-activity after their concentration and aisolation are the liquid scintillation counting and the proportional counter. In this work the beta activity of concentrated and aisolated Kr-85 samples measured in collaboration with the Max-Planck Institut fur Kernphyslk, Aussenstelle Freiburg. Samples taken both In Madrid and Frelburg are measured by proportional counters in the Max-Planck lnstitut, Freibury and by liquid scintillation counting in JEN, Madrid. The comparison of both measurements do not show appreciable discrepancy between the results obtained to both techniques. (Author)

Development of plastic scintillators for use in the field of radioprotection and environmental monitoring

International Nuclear Information System (INIS)

Mesquita, C.H. de; Hamada, M.M.; Chandra, U.

1986-01-01

A plastic scintillator detector based on available know how, for applications in radiological protection - whole body counting, continuous monitoring of air and measurement of low level alpha and beta radioactivity environmental samples is described. Results of method of preparation of the plastic scintillator using styrene monomer and PPO (scintillator), POPOP (wave lenght shifter) are described. For measurement of gamma radiation point sources of 60 Co, 137 Cs and 125 I were used and detected with plastic scintillator detectors prepared with various concentrations (% by weight) of PPO. The data of relative pulse heights are presented. For measurement of alpha and beta radioactivity in environmental samples, thin discs of plastic detector were machined and polished. (Author) [pt

Scintillating optical fibers for fine-grained hodoscopes

International Nuclear Information System (INIS)

Borenstein, S.R.; Strand, R.C.

1981-01-01

Fast detectors with fine spatial resolution will be needed to exploit high event rates at ISABELLE. Scintillating optical fibers for fine grained hodoscopes have been developed by the authors. A commercial manufacturer of optical fibers has drawn and clad PVT scintillator. Detection efficiencies greater than 99% have been achieved for a 1 mm fiber with a PMT over lengths up to 60 cm. Small diameter PMT's and avalanche photodiodes have been tested with the fibers. Further improvements are sought for the fiber and for the APD's sensitivity and coupling efficiency with the fiber

The HERMES recoil detector. Particle identification and determination of detector efficiency of the scintillating fiber tracker

Energy Technology Data Exchange (ETDEWEB)

Lu, Xianguo

2009-11-15

HERMES is a fixed target experiment using the HERA 27.6 GeV polarized electron/positron beams. With the polarized beams and its gas targets, which can be highly polarized, HERMES is dedicated to study the nucleon spin structure. One of its current physics programs is to measure deeply virtual Compton scattering (DVCS). In order to detect the recoiling proton the Recoil Detector was installed in the target region in the winter of 2005, taking data until the HERA-shutdown in the summer of 2007. The Recoil Detector measured energy loss of the traversing particles with its sub-detectors, including the silicon strip detector and the scintillating fiber tracker. This enables particle identification for protons and pions. In this work a systematic particle identification procedure is developed, whose performance is quantified. Another aspect of this work is the determination of the detector efficiency of the scintillating fiber tracker. (orig.)

Methyl salicylate as a medium for radioassay of 36Cl using a liquid scintillation spectrometer

International Nuclear Information System (INIS)

Wiebe, L.I.; Ediss, C.

1976-01-01

Methyl salicylate (MS), a high refractive index liquid with wave-shifting properties, has been used as a Cherenkov radiation generating medium for the radioassay of 36 Cl by liquid scintillation (LS) spectrometer. Comparative experiments, using both a standard toluene-based LS fluor and toluene alone, for the measurement of 36 Cl were undertaken. The methyl salicylate medium was found to perform at an intermediate counting efficiency, near that for the LS fluor. In the presence of moderate amounts of nitromethane, the MS was less susceptible to chemical quenching effects than either the fluor or toluene. Counting efficiencies for 36 Cl in MS, toluene and toluene fluor respectively were 82.4, 28.4 and 100.3 percent with a Picker Liquimat 220 LS spectrometer, and 91.6, 54.9 and 100.0 percent with a Searle Mark III LS spectrometer. The addition of nitromethane (11.3 percent of final volume) reduced these efficiencies to 50.5, 10.0 and 15.4 percent, and to 58.8, 12.4 and 19.0 percent, respectively. The data are discussed in relation to observed changes in the pulse height spectra. Chemical quench correction by ESCR and by SCR methods is reported

Calibration of the Accuscan II In Vivo System for I-131 Thyroid Counting

Energy Technology Data Exchange (ETDEWEB)

Orval R. Perry; David L. Georgeson

2011-07-01

This report describes the March 2011 calibration of the Accuscan II HpGe In Vivo system for I-131 thyroid counting. The source used for the calibration was an Analytics mixed gamma source 82834-121 distributed in an epoxy matrix in a Wheaton Liquid Scintillation Vial with energies from 88.0 keV to 1836.1 keV. The center of the detectors was position 64-feet from the vault floor. This position places the approximate center line of the detectors at the center line of the source in the thyroid tube. The calibration was performed using an RMC II phantom (Appendix J). Validation testing was performed using a Ba-133 source and an ANSI N44.3 Phantom (Appendix I). This report includes an overview introduction and records for the energy/FWHM and efficiency calibrations including verification counting. The Accuscan II system was successfully calibrated for counting the thyroid for I-131 and verified in accordance with ANSI/HPS N13.30-1996 criteria.

Scintillators for positron emission tomography

International Nuclear Information System (INIS)

Moses, W.W.; Derenzo, S.E.

1995-09-01

Like most applications that utilize scintillators for gamma detection, Positron Emission Tomography (PET) desires materials with high light output, short decay time, and excellent stopping power that are also inexpensive, mechanically rugged, and chemically inert. Realizing that this ''ultimate'' scintillator may not exist, this paper evaluates the relative importance of these qualities and describes their impact on the imaging performance of PET. The most important PET scintillator quality is the ability to absorb 511 keV photons in a small volume, which affects the spatial resolution of the camera. The dominant factor is a short attenuation length (≤ 1.5 cm is required), although a high photoelectric fraction is also important (> 30% is desired). The next most important quality is a short decay time, which affects both the dead time and the coincidence timing resolution. Detection rates for single 511 keV photons can be extremely high, so decay times ≤ 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so ≤5 ns fwhm coincidence pair timing resolution is required to identify events with narrow coincidence windows, reducing contamination due to accidental coincidences. Current trends in PET cameras are toward septaless, ''fully-3D'' cameras, which have significantly higher count rates than conventional 2-D cameras and so place higher demands on scintillator decay time. Light output affects energy resolution, and thus the ability of the camera to identify and reject events where the initial 511 keV photon has undergone Compton scatter in the patient. The scatter to true event fraction is much higher in fully-3D cameras than in 2-D cameras, so future PET cameras would benefit from scintillators with a 511 keV energy resolution < 10--12% fwhm

Quantitative Compton suppression spectrometry at elevated counting rates

International Nuclear Information System (INIS)

Westphal, G.P.; Joestl, K.; Schroeder, P.; Lauster, R.; Hausch, E.

1999-01-01

For quantitative Compton suppression spectrometry the decrease of coincidence efficiency with counting rate should be made negligible to avoid a virtual increase of relative peak areas of coincident isomeric transitions with counting rate. To that aim, a separate amplifier and discriminator has been used for each of the eight segments of the active shield of a new well-type Compton suppression spectrometer, together with an optimized, minimum dead-time design of the anticoincidence logic circuitry. Chance coincidence losses in the Compton suppression spectrometer are corrected instrumentally by comparing the chance coincidence rate to the counting rate of the germanium detector in a pulse-counting Busy circuit (G.P. Westphal, J. Rad. Chem. 179 (1994) 55) which is combined with the spectrometer's LFC counting loss correction system. The normally not observable chance coincidence rate is reconstructed from the rates of germanium detector and scintillation detector in an auxiliary coincidence unit, after the destruction of true coincidence by delaying one of the coincidence partners. Quantitative system response has been tested in two-source measurements with a fixed reference source of 60 Co of 14 kc/s, and various samples of 137 Cs, up to aggregate counting rates of 180 kc/s for the well-type detector, and more than 1400 kc/s for the BGO shield. In these measurements, the net peak areas of the 1173.3 keV line of 60 Co remained constant at typical values of 37 000 with and 95 000 without Compton suppression, with maximum deviations from the average of less than 1.5%

Determination of the absolute efficiency of an organic scintillator for neutrons with energies between 0.5 and 800 MeV

International Nuclear Information System (INIS)

Howe, S.D.; Lisowski, P.W.; Russell, G.J.; King, N.S.P.; Donnert, H.J.

1984-01-01

We have determined the absolute efficiency of an NE-213 scintillator for neutrons with energies from 0.5 to 800 MeV. The detector was 5.1 cm in diameter and 2.5 cm deep. The efficiencies were obtained for detector thresholds of 0.011, 0.48, 1.12, and 4.48 MeVee. Our results are compared to predictions of the STANTON computer code. (orig.)

Measurement methods for several properties of scintillator

International Nuclear Information System (INIS)

Luo Fengqun; Ji Changsong

1998-01-01

The current paper describes the experimental measurement methods for the relative light output, the relative energy conversion efficiency, the intrinsic amplitude resolution and the detection efficiency of the scintillators and their temperature effects

Neutron-gamma discrimination of boron loaded plastic scintillator

International Nuclear Information System (INIS)

Wang Dong; He Bin; Zhang Quanhu; Wu Chuangxin; Luo Zhonghui

2010-01-01

Boron loaded plastic scintillator could detect both fast neutrons thanks to hydrogen and thermal neutrons thanks to 10B. Both reactions have large cross sections, and results in high detection efficiency of incident neutrons. However, similar with other organic scintillators, boron loaded plastic scintillator is sensitive to gamma rays and neutrons. So gamma rays must be rejected from neutrons using their different behavior in the scintillator. In the present research zero crossing method was used to test neutron-gamma discrimination of BC454 boron loaded plastic scintillator. There are three Gaussian peaks in the time spectrum, they are corresponding to gamma rays, fast neutrons and flow neutrons respectively. Conclusion could be made that BC454 could clear discriminate slow neutrons and gamma, but the discrimination performance turns poor as the neutrons' energy becomes larger. (authors)

Neutron detector based on Particles of {sup 6}Li glass scintillator dispersed in organic lightguide matrix

Energy Technology Data Exchange (ETDEWEB)

Ianakiev, K.D., E-mail: ianakiev@lanl.gov; Hehlen, M.P.; Swinhoe, M.T.; Favalli, A.; Iliev, M.L.; Lin, T.C.; Bennett, B.L.; Barker, M.T.

2015-06-01

Most {sup 3}He replacement neutron detector technologies today have overlapping neutron–gamma pulse-height distributions, which limits their usefulness and performance. Different techniques are used to mitigate this shortcoming, including Pulse Shape Discrimination (PSD) or threshold settings that suppress all gammas as well as much of the neutrons. As a result, count rates are limited and dead times are high when PSD is used, and the detection efficiency for neutron events is reduced due to the high threshold. This is a problem in most applications where the neutron–gamma separation of {sup 3}He detectors had been essential. This challenge is especially severe for neutron coincidence and multiplicity measurements that have numerous conflicting requirements such as high detection efficiency, short die-away time, short dead time, and high stability. {sup 6}Li-glass scintillators have excellent light output and a single peak distribution, but they are difficult to implement because of their gamma sensitivity. The idea of reducing the gamma sensitivity of {sup 6}Li-glass scintillators by embedding small glass particles in an organic light-guide medium was first presented by L.M. Bollinger in the early 60s but, to the best of our knowledge, has never been reduced to practice. We present a proof of principle detector design and experimental data that develop this concept to a large-area neutron detector. This is achieved by using a multi-component optical medium ({sup 6}Li glass particles attached to a glass supporting structure and a mineral oil light guide) which matches the indices of refraction and minimizes the absorption of the 395 nm scintillator light. The detector design comprises a 10 in. long tube with dual end readout with about 3% volume density of {sup 6}Li glass particles installed. The presented experimental data with various neutron and gamma sources show the desired wide gap between the neutron and gamma pulse height distributions, resulting in a

Comparison of plastic scintillating fibres and capillaries filled with liquid scintillator

International Nuclear Information System (INIS)

Cardini, A.; Cavasinni, V.; Girolamo, B. di; Flaminio, V.; Golovkin, S.V.; Gorin, A.M.; Kulichenko, A.V.; Kushnirenko, A.E.; Pyshev, A.I.; Manuilov, I.; Vasilchenko, V.G.

1994-01-01

A comparison is made between the light yield, attenuation length, time response and light propagation speed in plastic scintillating fibres (SCSF-38 and Kuraray-3HF) and quartz capillaries filled with liquid scintillator (LS) 1-methilnaphthalene (1MN) doped with new dyes R45 and R39. The inner diameter of capillaries and diameter of plastic fibres is 0.5 mm. The number of photoelectrons detected at the far end (2 m) was 2.9 for capillaries filled with 1MN+3 g/l R45 while it was 1.8 times smaller in the case of SCSF-38 and 3 times smaller in the case of Kuraray 3HF plastic fibres. Taking into account the quantum efficiency of the photodetector used these reduction factors became 3.0 and 2.0, respectively. Good attenuation length, high light output and also excellent radiation resistance of capillaries filled with LS (>60 Mrad, measured elsewhere) show that they are a very promising alternative to plastic scintillating fibres for future applications in tracking detectors and calorimeters. ((orig.))

An Efficient Digital Pulse Shape Discrimination Technique for Scintillation Detectors Based on FPGA

International Nuclear Information System (INIS)

Kamel, M.S.

2014-01-01

Different techniques for pulse discrimination (PSD) of the scintillation pulses have been developed. The PSD of scintillation pulese can been used in several applications as Positron Emission Topography (PET) system. Each technique analyzes the resulting pulses from the absorption of radiation in the scintillation pulses were filtered and digitized then it is captured using DAQ, and it sent to the host computer for processing. The spatial resolution of images that generated in PET system can be improved by applying the proposed PSD. In this thesis various digital PSD techniques are proposed to discriminate the scintillation pulses. These techniques are based on discrete sine transform (DST). discrete cosine transform (DCT). Discrete hartley transform (DHT), Discrete Goertzel transform (DGT),and principal component analysis (PCA). Then the output coefficients of the discrete transforms are classified using one of the following classifiers T-test,tuned, or support vector machine (SVM).

Performance of coincidence-based PSD on LiF/ZnS Detectors for Multiplicity Counting

Energy Technology Data Exchange (ETDEWEB)

Robinson, Sean M.; Stave, Sean C.; Lintereur, Azaree; Siciliano, Edward R.; Cowles, Christian C.; Kouzes, Richard T.; Behling, Richard S.

2016-10-06

Abstract: Mass accountancy measurement is a nuclear nonproliferation application which utilizes coincidence and multiplicity counters to verify special nuclear material declarations. With a well-designed and efficient detector system, several relevant parameters of the material can be verified simultaneously. 6LiF/ZnS scintillating sheets may be used for this purpose due to a combination of high efficiency and short die-away times in systems designed with this material, but involve choices of detector geometry and exact material composition (e.g., the addition of Ni-quenching in the material) that must be optimized for the application. Multiplicity counting for verification of declared nuclear fuel mass involves neutron detection in conditions where several neutrons arrive in a short time window, with confounding gamma rays. This paper considers coincidence-based Pulse-Shape Discrimination (PSD) techniques developed to work under conditions of high pileup, and the performance of these algorithms with different detection materials. Simulated and real data from modern LiF/ZnS scintillator systems are evaluated with these techniques and the relationship between the performance under pileup and material characteristics (e.g., neutron peak width and total light collection efficiency) are determined, to allow for an optimal choice of detector and material.

Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators.

Science.gov (United States)

Wieczorek, Anna; Dulski, Kamil; Niedźwiecki, Szymon; Alfs, Dominika; Białas, Piotr; Curceanu, Catalina; Czerwiński, Eryk; Danel, Andrzej; Gajos, Aleksander; Głowacz, Bartosz; Gorgol, Marek; Hiesmayr, Beatrix; Jasińska, Bożena; Kacprzak, Krzysztof; Kamińska, Daria; Kapłon, Łukasz; Kochanowski, Andrzej; Korcyl, Grzegorz; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Kubicz, Ewelina; Kucharek, Mateusz; Mohammed, Muhsin; Pawlik-Niedźwiecka, Monika; Pałka, Marek; Raczyński, Lech; Rudy, Zbigniew; Rundel, Oleksandr; Sharma, Neha G; Silarski, Michał; Uchacz, Tomasz; Wiślicki, Wojciech; Zgardzińska, Bożena; Zieliński, Marcin; Moskal, Paweł

2017-01-01

A novel plastic scintillator is developed for the application in the digital positron emission tomography (PET). The novelty of the concept lies in application of the 2-(4-styrylphenyl)benzoxazole as a wavelength shifter. The substance has not been used as scintillator dopant before. A dopant shifts the scintillation spectrum towards longer wavelengths making it more suitable for applications in scintillators of long strips geometry and light detection with digital silicon photomultipliers. These features open perspectives for the construction of the cost-effective and MRI-compatible PET scanner with the large field of view. In this article we present the synthesis method and characterize performance of the elaborated scintillator by determining its light emission spectrum, light emission efficiency, rising and decay time of the scintillation pulses and resulting timing resolution when applied in the positron emission tomography. The optimal concentration of the novel wavelength shifter was established by maximizing the light output and it was found to be 0.05 ‰ for cuboidal scintillator with dimensions of 14 mm x 14 mm x 20 mm.

Determining reactor fuel elements broken by Cerenkov counting

International Nuclear Information System (INIS)

Guo Juhao; Dong Shiyuan; Feng Yuying

1996-01-01

The basis and method of determining fuel elements broken in a reactor by Cerenkov counting measured with liquid scintillation spectrometer are introduced. The radioactive characteristic of the radiation nuclides generating Cherenkov radiation in the primary water of 200 MW nuclear district heating reactor is analyzed. The activity of the activation products in the primary water and the fission products in the fuel elements are calculated. A feasibility of Cerenkov counting measure was analyzed. This method is simple and quick

Linear position sensitive neutron detector using fiber optic encoded scintillators

International Nuclear Information System (INIS)

Davidson, P.L.; Wroe, H.

1983-01-01

A linear position sensitive slow neutron detector with 3 mm resolution is described. It uses the fiber optic coding principle in which the resolution elements are separate pieces of lithium loaded glass scintillator each coupled by means of flexible polymer optical fibers to a unique combination of 3 photo multipliers (PM's) out of a bank of 12. A decoder circuit repsponds to a triple coincidence between PM outputs and generates a 12 bit work which identifies the scintillator element which stopped the incident neutron. Some details of the construction and decoding electronics are given together with test results obtained using a laboratory isotope neutron source and a monochomated, collimated neutron beam from a reactor. The count rate in the absence of neutron sources is 2 to 3 c min - 1 per element; the element to element variation in response to a uniform flux is a few percent for 95% of the elements; the resolution as measured by a 1 mm wide prode neutron beam is 3 mm; the relative long term stability is about 0.1% over 3 days and the detection efficiency measured by comparison with an end windowed, high pressure gas counter is about 65% at a neutron wavelength of 0.9A 0

Preparation of 'dead water' for low background liquid scintillation counting

International Nuclear Information System (INIS)

Morishima, Hiroshige; Koga, Taeko; Niwa, Takeo; Kawai, Hiroshi

1987-01-01

'Dead water', low level tritiated water is indispensable to measure tritium concentration in environmental waters using a low background liquid scintillation counter. Water produced by combustion of natural gas, or deep sea water etc. are usually used for the above purpose. A new method of reducing tritium concentration in natural water has been introduced for preparation of 'dead water'. This method is to combine hydrogen-oxygen mixture produced by water electrolysis with hopcalite catalyzer at 700 deg C. Deep well water was electrolized up to 2/3 volume, and tritium concentration of recombined water was reduced to be about one third of that of the original one. (author)

Calculated Absolute Detection Efficiencies of Cylindrical Nal (Tl) Scintillation Crystals for Aqueous Spherical Sources

Energy Technology Data Exchange (ETDEWEB)

Strindehag, O; Tollander, B

1968-08-15

Calculated values of the absolute total detection efficiencies of cylindrical scintillation crystals viewing spherical sources of various sizes are presented. The calculation is carried out for 2 x 2 inch and 3 x 3 inch Nal(Tl) crystals and for sources which have the radii 1/4, 1/2, 3/4 and 1 times the crystal radius. Source-detector distances of 5-20 cm and gamma energies in the range 0.1 - 5 MeV are considered. The correction factor for absorption in the sample container wall and in the detector housing is derived and calculated for a practical case.

Ion induced scintillation in organic solids: development of an average track model,degradation of the scintillation intensity and dosimetric applications

International Nuclear Information System (INIS)

Broggio, D.

2004-12-01

This work deals with a specific aspect of the ion-matter interaction: the scintillation induced by ions in organic materials. In the first chapter we tackle the issue in a theoretical way by proposing a method to compute the radial doses within the framework of the mean track model. We have developed a model based on the Lewis transport equation and on the Spencer distribution of the loss energy in order to take into account the transport of secondary electrons in a more realistic way. In the second chapter we study the physical mechanisms that trigger ion-induced scintillation. Ion-induced scintillation is featured by the dependence in charge number of the intensity of scintillation for ions with same energy loss and by the saturation of the scintillation efficiency for ions with high stopping-power. We have applied our model of radial doses to ion-induced scintillation. In the third chapter we study the gradual degradation of the scintillation intensity and ion-induced chemical damages. In the last chapter we propose a prototype of dosimeters based on the combination of scintillators and optical fibers that allows the real-time measurement of the dose delivered by a carbon ion beam in therapeutical use conditions. This dosimeter gives the relationship between the dose and the scintillation intensity but its accuracy is not yet sufficient for uses in radiotherapy. (A.C.)

Preparation of 45Ca(HDEHP)n and (CaH{sub 1}50{sub 2})2 samples for liquid scintillation counting, compared to 45caCl{sub 2} results; Preparacion de Ca (HDEHP)n y (C{sub 8}H{sub 1}50{sub 2})2 marcados con 45Ca y estudio comparativo con 4 5ca Cl2 en medidas por centelleo liquido

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, L.; Arcos, J. M. los; Grau Malonda, A.

1994-07-01

A procedure for preparation of liquid scintillation counting organic samples of the Di-2-ethylhexyl phosphate calcium complex and the 2-ethylhexanoate calcium salt, labelled with 45Ca, is described. The chemical quench, the counting stability and spectral evolution of both compounds is studied in six scintillators,Toluene-alcohol, Dioxane-naphtalene, Hi safe II, Ultimate-Gold and Instagel, and compared to results obtained from a commercial solution of 4 5CaCl2. (Author) 7 refs.

Optical efficiency for fission fragment track counting in Muscovite solid state track recorders

International Nuclear Information System (INIS)

Roberts, J.H.; Ruddy, F.H.; Gold, R.

1984-01-01

In order to determine absolute fission rates from thin actinide deposits placed in direct contact with Muscovite Solid State Track Recorders, it is necessary to know the efficiency with which fission fragment tracks are recorded. In this paper, a redetermination of the 'optical efficiency', i.e. the fraction of fission events recorded and observed in the Muscovite is reported. The value obtained from a well-calibrated thin deposit of 252 Cf and Muscovite etched about 90 min. in 49% HF at room temperature, is 0.9875 +- 0.0085. Manual counting was used. Preliminary results from a deposit of 242 Pu are also reported, along with preliminary comparisons of track counting with an automated system. Reasons for the discrepancy of the optical efficiency reported here with an earlier measurement are also reported. (author)

Memory effect, resolution, and efficiency measurements of an Al2O3 coated plastic scintillator used for radioxenon detection

Science.gov (United States)

Bläckberg, L.; Fritioff, T.; Mårtensson, L.; Nielsen, F.; Ringbom, A.; Sjöstrand, H.; Klintenberg, M.

2013-06-01

A cylindrical plastic scintillator cell, used for radioxenon monitoring within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty, has been coated with 425 nm Al2O3 using low temperature Atomic Layer Deposition, and its performance has been evaluated. The motivation is to reduce the memory effect caused by radioxenon diffusing into the plastic scintillator material during measurements, resulting in an elevated detection limit. Measurements with the coated detector show both energy resolution and efficiency comparable to uncoated detectors, and a memory effect reduction of a factor of 1000. Provided that the quality of the detector is maintained for a longer period of time, Al2O3 coatings are believed to be a viable solution to the memory effect problem in question.

Memory effect, resolution, and efficiency measurements of an Al2O3 coated plastic scintillator used for radioxenon detection

International Nuclear Information System (INIS)

Bläckberg, L.; Fritioff, T.; Mårtensson, L.; Nielsen, F.; Ringbom, A.; Sjöstrand, H.; Klintenberg, M.

2013-01-01

A cylindrical plastic scintillator cell, used for radioxenon monitoring within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty, has been coated with 425 nm Al 2 O 3 using low temperature Atomic Layer Deposition, and its performance has been evaluated. The motivation is to reduce the memory effect caused by radioxenon diffusing into the plastic scintillator material during measurements, resulting in an elevated detection limit. Measurements with the coated detector show both energy resolution and efficiency comparable to uncoated detectors, and a memory effect reduction of a factor of 1000. Provided that the quality of the detector is maintained for a longer period of time, Al 2 O 3 coatings are believed to be a viable solution to the memory effect problem in question

Scintillation response of organic and inorganic scintillators

CERN Document Server

Papadopoulos, L M

1999-01-01

A method to evaluate the scintillation response of organic and inorganic scintillators to different heavy ionizing particles is suggested. A function describing the rate of the energy consumed as fluorescence emission is derived, i.e., the differential response with respect to time. This function is then integrated for each ion and scintillator (anthracene, stilbene and CsI(Tl)) to determine scintillation response. The resulting scintillation responses are compared to the previously reported measured responses. Agreement to within 2.5% is observed when these data are normalized to each other. In addition, conclusions regarding the quenching parameter kB dependence on the type of the particle and the computed values of kB for certain ions are included. (author)

Scintillation counter with MRS APD light readout

International Nuclear Information System (INIS)

Akindinov, A.; Bondarenko, G.; Golovin, V.; Grigoriev, E.; Grishuk, Yu.; Mal'kevich, D.; Martemiyanov, A.; Ryabinin, M.; Smirnitskiy, A.; Voloshin, K.

2005-01-01

START, a high-efficiency and low-noise scintillation detector for ionizing particles, was developed for the purpose of creating a high-granular system for triggering cosmic muons. Scintillation light in START is detected by MRS APDs (Avalanche Photo-Diodes with Metal-Resistance-Semiconductor Structure), operated in the Geiger mode, which have 1mm 2 sensitive areas. START is assembled from a 15x15x1cm 3 scintillating plastic plate, two MRS APDs and two pieces of wavelength-shifting optical fiber stacked in circular coils inside the plastic. The front-end electronic card is mounted directly on the detector. Tests with START have confirmed its operational consistency, over 99% efficiency of MIP registration and good homogeneity. START demonstrates a low intrinsic noise of about 10 -2 Hz. If these detectors are to be mass-produced, the cost of a mosaic array of STARTs is estimated at a moderate level of 2-3kUSD/m 2

Gamma spectra analysis from a NaI(Tl) scintillation detector using a micro-computer

International Nuclear Information System (INIS)

Levinson, S.

1990-01-01

A software package of programs was devloped for qualitative and quantitative evaluation of gamma ray spectra obtained from a NaI(Tl) scintilation counter, by means of a micro-computer. The programs can easily be transformed for use with a Ge(Li) detector. The various algorithms enable automatic analyzing of a spectrum and also interactive or manual mode. The graphic programs display the measured spectrum as well as spectra of standard radionuclides which helps in the determination of peaks and related radionuclides in the spectrum. The peak search is carried out on a smoothed spectrum and is done by checking the behaviour of the second and third derivatives. The algorithm solves the problem of overlapping peaks and performs gaussian fitting, if necessary. Determination of the various radionuclides in the spectrum is done by linear minimum least squares techniques. Overall analysis of the radionuclides activities in the spectrum is obtained for samples of various counting geometries. In addition, a model was developed for efficiency calibration of flat 3X3 inch NaI(Tl) detectors for different samples measured in various counting geometries. It is based on point source experimental efficiency curve fitting. (author)

Development of a scintillation flow-cell detection system for environmental restoration and waste management applications

International Nuclear Information System (INIS)

DeVol, T.A.; Branton, S.D.; Fjeld, R.A.

1996-01-01

A flow-cell detection system was developed utilizing a coincidence circuit and tested with BaF 2 , CaF 2 :Eu and scintillating glass. The coincidence detection system reduced the background from ∼200 cps to ∼0.5 cps. The detection efficiencies for these cells ranged from 0.38 to 0.66 for 45 Ca beta particles (E max = 0.257 MeV) and from 0.45 to 0.52 for 233 U alpha particles (E α = 4.8 MeV). The minimum detectable activity was calculated for a 30 s count time and determined to be in the range of 1-2 Bq

Production low cost plastic scintillator by using commercial polystyrene

International Nuclear Information System (INIS)

2011-01-01

were produced with those determined parameters in 12 June 2008. Plastic blocks prepared were optically and mechanically tested and its response against various radioactive sources was measured. The results regarding the optical, mechanical and detection properties of blocks produced in 10x5x40 cm dimension were compared with commercial LODLUM Scintillator (main component PVT) produced by US in 13x8x120 cm dimensions. It was found that optical and mechanical properties of blocks produced in SANAEM are similar to or better than that of LODLUM. Plastic scintillator produced in SANAEM has shown the same response and counting characteristics that obtained by LODLUM, but proportional to its area and/or volume specifications. This study has shown that plastic scintillators imported can be produced in SANAEM domestically and be used for detection of radioactive materials within the country or border gates.

Scintillating fibre detectors using position-sensitive photomultipliers

International Nuclear Information System (INIS)

Agoritsas, V.; Bergdolt, A.M.; Bing, O.; Bravar, A.; Ditta, J.; Drevenak, R.

1995-01-01

Scintillating fibre technology has made substantial progress, and has demonstrated great potential for fast tracking and triggering in high luminosity experiments in Particle Physics. Some recent issues of the RD-17 project at CERN are presented for fast and precise readout of scintillating fibre arrays, as well as for upgrade of position-sensitive photomultipliers. Excellent matching of the scintillating fibre and the position-sensitive photomultiplier, in particular in time characteristics, allowed to achieve excellent detector performances, typically a spatial resolution of ∼ 125 μm with time resolution better than 1 ns and detection efficiency greater than 95%. (author)10 refs.; 25 figs.; 1 tab

Performance comparison of scintillators for alpha particle detectors

Energy Technology Data Exchange (ETDEWEB)

Morishita, Yuki [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Yamamoto, Seiichi [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Izaki, Kenji [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

2014-11-11

Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd{sub 2}Si{sub 2}O{sub 7} (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM.