NaI (Tl) detector

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Determination of Natural Radioactivity  in Soil Samples around Gold Mining Area in Khamkeut District, Bolikhamxay Province,Laos Using Gamma Ray Spectrometer with NaI (Tl) Detector

Determination of Natural Radioactivity in Soil Samples around Gold Mining Area in Khamkeut District, Bolikhamxay Province,Laos Using Gamma Ray Spectrometer with NaI (Tl) Detector

U series. Radiological hazard parameters are calculated based on the specific radioactivity of 40 K, 226 Ra and 232 Th in the soil samples [1-3]. The low resolution energy of the NaI(Tl) detector with full width at half maximum (FWHM) is 70 keV at the 1332 keV, there are many overlapping full energy peaks of natural radiation isotopes. Moreover, the radioactivity of environmental sampleswasvery small, so the appearance of full energy peaks were not clear. For the NaI detector, radioactivity is based on detection gamma radiation of 1460.8 keV for 40 K, from 214 Bi (1764 keV) for 226 Ra series and from 208 Tl (2614 keV) for series [4, 5]. The activity of each isotope is determined based on the net count rate (cps) measured in energy region of interest (ROI) for each isotope. The net count rate measured in the i –th ROIcan be expessed as follows [4]:
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Validation and Uncertainty Quantification of a 1x2" NaI Collimated Detector Using Detector Response Functions Created by g03.

Validation and Uncertainty Quantification of a 1x2" NaI Collimated Detector Using Detector Response Functions Created by g03.

Overall, the simulated detector responses predicted by Gardner’s model predicted the highest intensity peak region of the experimental spectra fairly well, but had some difficulty in the continuum and secondary peak regions. In the highest intensity peak region of the response, most of the computed spectrum lay within two standard deviations of the experimental spectrum’s centroid. The continuum discrepancies between the predicted and measured responses in the calibration sources appear to stem from miscalibration of the electron range multiplier (Equation 2.4) for the collimated 1x2" NaI detector. Gardner’s current model was validated only for larger bare NaI detectors and not for collimated detectors and therefore some differences were expected. Whereas, significant underestimation of the secondary peaks occurred in the highly enriched uranium (HEU) disc spectra most likely due to outside crystal scattering with the detector collimator and other components.
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Direct Analytical Method to Calculate  Photopeak Efficiency and Photopeak  Attenuation Coefficient of NaI(Tl)  Well Type Detector

Direct Analytical Method to Calculate Photopeak Efficiency and Photopeak Attenuation Coefficient of NaI(Tl) Well Type Detector

In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating point sources (with photon energy: 0.245, 0.344, 0.662, 0.779, 0.964, 1.1732, 1.333 and 1.408 MeV) placed outside the detector well. These energies were obtained from 152 Eu, 137 Cs and 60 Co. The re-

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Determination of Full Energy Peak Efficiency of NaI(Tl) Detector Depending on Efficiency Transfer Principle for Conversion Form Experimental Values

Determination of Full Energy Peak Efficiency of NaI(Tl) Detector Depending on Efficiency Transfer Principle for Conversion Form Experimental Values

Peak Efficiency (FEPE) for these detectors have been calculated for point sources placed at different positions on the detector axis using the analytical approach of the effective solid angle ratio. This approach is based on the direct mathematical method reported by Selim and Abbas [1,2] and has been used successfully before to calibrate the cylin- drical, parallelepiped, and 4π NaI(Tl) detectors by using point, plane and volumetric sources. In addition, the present method is free of some major inconveniences of the conventional methods.

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Calculation of Full Energy Peak Efficiency of NaI (Tl) Detectors by New Analytical Approach for Cylindrical Sources

Calculation of Full Energy Peak Efficiency of NaI (Tl) Detectors by New Analytical Approach for Cylindrical Sources

Where Z′ 1 and Z 3 ′ are as identified befo re in Table 3. In the case of a co-a xial cylindrical source with radius greater than the radius of the detector, there are t wo probabilit ies to be considered; the first probability that the lateral d istance of the source is smalle r than the detector circula r face rad ius, i.e. ρ ≤ R and the second probability that the lateral distance of the source is greater than the detector circula r face rad ius, i.e. ρ > R and in the two cases, there is only one path to the photon for the way out fro m the source which is e xit fro m the base and is given by:
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PAPER / ARTICLE  TITLE   –     NAME OF AUTHOR

PAPER / ARTICLE  TITLE   –     NAME OF AUTHOR

Abstract: By using well-developed technique citrate gel auto combustion, we synthesized the material as samples which is used to extract the mass attenuation coefficients. After that the samples were taken to gamma ray scintillation process. In this study, the energies 30.85 KeV, 42 KeV, 59.54 KeV, 512 KeV and 661.6 KeV are used. A well-shielded gamma-ray spectrometry based on NaI (Tl) scintillation detector measures the intensity of the transmitted beam.The mass attenuation coefficient values are measured from the experiment and compared with theoretical values by using the XCOM program and the result is all obtained data perfectly matched each other.
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The Dark Matter annual modulation results from DAMA/LIBRA

The Dark Matter annual modulation results from DAMA/LIBRA

The obtained model independent evidence is compatible with a wide set of scenarios regarding the nature of the DM candidate and related astrophysical, nuclear and particle Physics. For examples some given scenarios and parameters are discussed e.g. in Refs. [2, 4–11] and in Appendix A of Ref. [17]. Further large literature is available on the topics [49]; other possibilities are open. Here we just recall the recent papers [48, 50] where the DAMA/NaI and DAMA/LIBRA results, which fulfill all the many peculiarities of the model independent DM annual modulation signature, are examined under the particular hypothesis of a light-mass DM candidate particle interacting with the detector nuclei by coherent elastic process. In particular, in Ref. [48] allowed regions are given for DM candidates interacting by elastic scattering on nuclei including some of the existing uncertainties; comparison with theoretical expectations for neutralino candidate and with the recent possible positive hint by CoGeNT [51] is also discussed there (see Fig. 5), while comparison with possible positive hint by Cresst [52] is discussed in Ref. [50].
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Characteristics of alpha, gamma and nuclear recoil pulses from NaI(Tl) at 10-100 keV relevant to dark matter searches

Characteristics of alpha, gamma and nuclear recoil pulses from NaI(Tl) at 10-100 keV relevant to dark matter searches

Co gamma source was used to obtain pulse shapes from high-energy gammas. These gammas undergo Compton scattering inside the crystal producing electrons which deposit energy measured by the detector. To measure the shapes of the integrated pulses induced by nuclear recoils (sodium and iodine), the crystal was irradiated by neutrons from a 252

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Searching for Dark Matter at the Stawell Underground Physics Laboratory

Searching for Dark Matter at the Stawell Underground Physics Laboratory

The final SABRE setup will be two identical experiments with 50-60 kg of NaI crystals. A prototype, or com- missioning detector will be conducted with a small 1- 2 kg crystal. Each crystal will be enclosed in a self- contained module consisting of the crystal itself and two low-radioactivity, high quantum efficiency photomultiplier tubes. The phototubes are optically coupled to opposite sides of the crystal. These components are then sealed in a light and air tight low radioactivity metal container. The crystal detectors are placed inside of a cylindrical liq- uid scintillator, 1.5 m diameter and 1.5 m length, detector that is shielded from environment background with pas- sive shielding. The passive shielding is still be designed for the respective locations at Gran Sasso and Stawell. The liquid scintillator detector is able to reject internal radioac- tivity as well as external γ ray backgrounds. The scin- tillator vessel will contain approximately 2 tonnes of lin- ear alkylbenzene (LAB). Approximately twenty 20.2 cm Hamamatsu R5912 PMTs will be placed at the ends of the cylindrical vessel.
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Gamma ray spectrometric analysis of sand samples from selected beaches on coastline of Kenya

Gamma ray spectrometric analysis of sand samples from selected beaches on coastline of Kenya

products of decay. Beach sands are weathering resistant residuals of geological formations which gets to the beach by erosion from mainland or deposition through waves and current action from the ocean. Waves wash back lighter grains leaving behind heavy ones which may be rich in minerals such as zircon, ilmenite, garnet and monazite, which are associated with elevated levels of naturally occurring radionuclides. In addition to that, Indian Ocean waters are polluted with traces of oil spillages and radioactive wastes from damping all of which may be brought to the beach by wave action and have great association with these radionuclides. Low level whole body background radiation exposure to the public for a long time can lead to some of the radiation health effects like acute leucopoenia, leukemia, cancer and genetic effects. Thus, public awareness of natural radiation levels in these beaches is necessary. Studies of beach sand in other countries have shown higher levels in the radiological parameters than the recommended limit. Radioactivity levels from natural radionuclides on Kenyan beaches is not known despite the fact that many people spend a lot of time relaxing in these beaches. The objective of this study is to assess human exposure to natural sources of radiation by measurements of their activity concentration using NaI (Tl) gamma ray detector, then to determine the radiological parameters like radium equivalent, absorbed dose rates and hazard indices. Sand samples were obtained from (Shanzu, Nyali, Kenyatta on North coast and Tiwi, Shelly, Diani on South coast). Activity concentration of 40 K ranged between 653 ± 32 Bq/kg and 2117 ± 105 Bq/kg with a mean of 1254 ± 62 Bq/kg, 238 U ranged between 43 ± 2 and 118 ± 5 Bq/kg with a mean
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Search for a dark matter-induced annual modulation signal in NaI(Tl) with the COSINE-100 experiment

Search for a dark matter-induced annual modulation signal in NaI(Tl) with the COSINE-100 experiment

grounds [28]. Each NaI(Tl) crystal is optically coupled to two photomultiplier tubes (PMTs), each of which de- tects scintillation photons with the signals recorded as 8 µs waveforms [29]. These eight crystals are referred to as Crystal-1 (C1) to Crystal-8 (C8). C1, C5, and C8 are excluded from this analysis due to their high background (about twice that of the other crystals), high noise rate (C1), and low light yield (C5 & C8), for a total effective mass of 61.3 kg. The detector is surrounded by passive and active shielding that include, starting from the in- side, copper plates of 3 cm in total thickness, 20 cm of lead, and 3 cm of 37 plastic scintillator panels for cosmic ray muon tagging [30]. More details of the experimental apparatus are presented in Ref. [31].
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Background model for the NaI(Tl) crystals in COSINE-100

Background model for the NaI(Tl) crystals in COSINE-100

dom locations inside a NaI(Tl) crystal for the cases with and without the LS veto. From these simulations, we determined that the Crystal-6 tagging efficiency by other crystals without LS is 31.7 ± 0.1 % and by the LS only is 64.9±0.2 %. The total combined efficiency is 81.7±0.3 %. The efficiency is measured in the crystal energy range between 2 and 6 keV by requiring the LS energy deposit be larger than 20 keV. Efficiencies vary depending on the crystal location in the detector. For example, Crystal-1 (at the corner of the array) shows higher coverage by the LS (75 %) than neighboring crys- tals (17 %), but the combined efficiency is similar to
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Decay modes of the systems formed in the reactions 78Kr+40Ca and 86Kr+48Ca

Decay modes of the systems formed in the reactions 78Kr+40Ca and 86Kr+48Ca

This last method was recently upgraded in CHIMERA [10], and it al- lowed to work for the first time in a low energy regime, where most of the particles are stopped in the first stage of the telescope. In Figure 1 a schematic view of a charge pre-amplifier utilized in order to perform such discrimination is reported. We managed to obtain a very good charge iden- tification by using the PSD method for particles stopped in silicon detector, as it can be verified by looking at Figure 2, where a E-RiseTime plot is presented for the n-poor system 78 Kr+ 40 Ca at 10 A · MeV at θ=34 ◦ .
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Pressure Induced Structural Phase Transition, Metallization and Superconductivity in SodiumIodide (NaI)

Pressure Induced Structural Phase Transition, Metallization and Superconductivity in SodiumIodide (NaI)

Abstract The structural phase transition and metallization of the simple alkali iodide, sodium iodide (NaI) is investigated through their band structures. The band structure, density of states (DOS) and total energy are computed as a function of volume for both NaCl and CsCl phases using the full potential linear muffin-tin orbital (FP-LMTO) method. The phase transition pressure (P T )

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Structure and Ionic Diffusion in Molten NaI, RbI, and NaI-RbI mixture

Structure and Ionic Diffusion in Molten NaI, RbI, and NaI-RbI mixture

density, respectively. The experimental ionic conductivities and diffusion coefficients are reasonably reproduced by MD simulations. Since ionic conductivities and diffusion coefficients for the mixture have not been measured, the MD results for the mixture cannot be compared to experimental data at this time. Although we used the rigid ion model in this study, if we consider a polarizable ion model, the cation diffusion would become large. However, polarization effects on NaI, RbI, and their mixture would be weak compared to silver (or cupper) halides [13-20] and zinc halides [21,22].
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BIO PROSPECTING OF ENDOPHYTIC BACTERIA FROM MEDICINAL PLANT

BIO PROSPECTING OF ENDOPHYTIC BACTERIA FROM MEDICINAL PLANT

Plants are generally associated with diverse microorganisms. Endophytic organisms are those that colonize the plant internal tissue showing no external sign of infection or negative effect on there. Endophytic microbes from medicinal plants are good source of functional metabolites. Endophytic microorganisms can be derived from any part of the plant like bark, leaves, flowers, fruits, roots, seeds etc. In the present study, efforts have been made to isolate and physiological activity of endophytic bacteria inhabiting leaves of medicinal plants such as Kasarali (Catharanthus roseus L.), Thuthuvalai (Solanum trilobatum L. ) and Tulsi (Ocimum sanctum L.) which are growing in the Trichy region. The density of endophytic populations recovered in nutrient agar medium, which varied from 4.26 x 10 5 to 1.34 x 10 5 CFUg -1 per fresh weight. Colonization frequency and isolation rates 42.22, 37.78, 46.67 % and 21.05%, 17.65% and 23.81% in kasarali, thuthuvalai and tulsi respectively. Among the 12 isolates, KA-1, KA-2, KA-3, TV-5, TV-7, TL-8, TL-9 AND TL-11 were identified as Bacillus sp. KA-4, TV-6 and TL-10 were identified as Pseudomonas sp and TL-12 as Klebsiella sp. Among the 12 isolates, 9 isolates had amylolytic, lipolytic and proteolytic activity with different zone of clearance. Among the 12 isolates, 11isolates had cellulolytic activity with different zone of clearance. Among the 12 isolates, nine isolates showed antibacterial activity against either gram-positive or gram-negative bacteria. The endophytic bacterial extracts were more effective in gram-positive bacteria than gram-negative bacteria. The MIC of ethyl acetate of
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Fuzzy TL uniform spaces

Fuzzy TL uniform spaces

The main purpose of this paper is to introduce a new structure that is a fuzzy TL-uniform space. We show that our structure generates a fuzzy topological space, precisely, a fuzzy T- locality space. Also, we deduce the concept of level uniformities of a fuzzy TL-uniformity. We connect the category of fuzzy TL-uniform spaces with the category of uniform spaces. We establish a necessary and sufficient condition, under which a fuzzy TL-uniformity is probabilistic pseudometrizable. Finally, we define a functor from the category of fuzzy TL-uniform spaces into the category of fuzzy T-locality spaces and we show that it pre- serves optimal lifts.
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Hybrid modular multilevel converter with reduced three-level cells in hvdc transmission system

Hybrid modular multilevel converter with reduced three-level cells in hvdc transmission system

Abstract—A hybrid MMC with reduced three-level (TL) cells is proposed. As well as the dc fault blocking capability, the proposed hybrid MMC provides the benefits of: lower conduction losses; fewer diode and switching devices, and; fewer shoot-through modes. Guidelines are developed to determine the required number of three-level cells to block a dc-side fault. It is also demonstrated that a further reduction in the number a three-level cells is possible if a rise in cell current and voltage is acceptable. This reduction is investigated. A lower number of three-level cells reduces losses and capital cost further. The hybrid MMC with the reduced number of three-level cells proves to be the most attractive approach compared with other MMCs and hybrid MMCs. The semiconductor count and conduction loss are 92.1% and 90.3% respectively of that of the MMC based entirely on full-bridge cells, without exposing the semiconductors to significant fault currents and over-voltages. The simulation results demonstrate the feasibility of the proposed hybrid converter.
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Design and Development of Smart Robot Car for Border Security

Design and Development of Smart Robot Car for Border Security

Sensory network in our proposed system detect parameters like human presence, harmful gases, pistols, bombs, mines, fire etc at remote areas. In border areas, we know the entry of any human is totally prohibited. Through PIR (Pyroelectric Infrared Sensor) sensor we can detect presence of any human being in prohibited areas. In this proposed system, Metal detection sensor, gas detection sensor, temperature sensor, PIR sensors are used. Metal detector is used for detecting metals at the border areas because mines, bombs, pistols, electronic circuits are made up of metals. Temperature sensor measures the temperature of outside environment [10] and when temperature goes beyond the limits then according to feeded algorithm robot transmit the signals to user side where user is available to take action. Switching from automatic mode to user mode is very fast and from without any delay.
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Improving the MCLLS Method Applied to the In Vivo XRF Measurement of Lead in Bone by Using the Differential Operator Approach (MCDOLLS) and X-ray Coincidence Spectroscopy

Improving the MCLLS Method Applied to the In Vivo XRF Measurement of Lead in Bone by Using the Differential Operator Approach (MCDOLLS) and X-ray Coincidence Spectroscopy

years (Ao et al. 1997a; He et al. 1991; Lee et al. 2001). In this thesis, the benchmark experiment was carried out with the geometry shown in figure 2.2, in which the source-sample-detector angle was 120+10 degrees, as illustrated in the figure. A low energy Germanium detector was used (table 2.3). The experimental sample was made of the Plaster of Paris, with certified elemental weight fractions of hydrogen (0.6630%), carbon (0.5076%), oxygen (49.9990%), silicon (0.4874%), sulphur (20.8000%), calcium (27.2737%), iron (0.0839%), strontium (0.1691%), and lead (162 µg Pb / g Plaster). The density of the sample is 1 . 850 g cm 3 . The simulated spectrum is compared with the experimental spectrum in figure 2.3. Generally speaking, they show very good agreements in the full spectrum range. There are several potential sources of discrepancies, which are listed in the order of importance:
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