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1.
This work presents a new approach using nuclear track in solids methodology (NTSM) for the energy analysis of alpha-particles. This method is based on the quantitative relationship between the energy deposited in the polycarbonate by the geometrical parameters of the developed track after the chemical etching. We used separated calibrated sources of 239Pu and 241Am, and a mixed source with 239Pu, 241Am and 244Cm. CR-39 polycarbonate manufactured by Landauer Inc.® was selected as the detector material, because of its excellent response to these energies. The chemical etching was done in two steps: (a) pre-etching to avoid the irregularities on the surface of the material, and (b) chemical etching to develop the track. In both processes the temperature and pH of the solution need to be very controlled. The geometrical characteristics of the formed tracks were analyzed automatically by Digital Image System. The results show a distribution of track diameters as a function of the energies analyzed analogous to the pulses produced on the conventional electronic detection system. 相似文献
2.
H. B. Lück 《Journal of Radioanalytical and Nuclear Chemistry》1975,28(1-2):257-262
Recently a method using solid state track detectors for the energy determination of alpha-particles has been developed in the Central Institute for Nuclear Research at Rossendorf. The method shows a good accuracy and has an energy resolution which is sufficient for the application in several disciplines. The method is based on a determination of the particle ranges in the detector material. The particle energy can be calculated by the known energy—range relationship. In the energy range from 3 to 6 MeV, which is the energy region of the most alpha-emitters, the energy resolution is 50 keV. The accuracy under optimum conditions is about ±50 keV. The efficiency of the method depends on the particle energy and the energy resolution desired. The method can be used for the energy determination of alpha-particles above 2.7 MeV. 相似文献
3.
《Radiation Physics and Chemistry》2008,77(8):949-953
By adding ethylenediamine to the common etchant composition (potassium hydroxide, water, methanol and/or ethanol) in electrochemical etching of lexan polycarbonate detectors, a passive α-particle spectrometry is resulted in the energy range of 0.8–5.2 MeV. This spectrometry is based on the track size distributions, which have a tailed normal shape and FWHM of less than 0.5 MeV. Also the energies of α-particles emitted by a 226Ra micro-precipitated source and its α-emitter daughters, which were detected by this method, were in accord with that of a surface barrier detector. Consequently, this method can be developed for alpha spectrometry such as radon/thoron and their α emitter daughters’ detection, separation and measurements. 相似文献
4.
G. S. Sahoo S. P. Tripathy S. Paul S. D. Sharma D. S. Joshi T. Bandyopadhyay 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1289-1293
The neutron dose is estimated by linear energy transfer (LET) spectrometry method for two reactions, viz. 1H+9Be and 1H+12C at 20 MeV proton energy using CR-39 track detectors. The LET spectrum is generated from the major, minor radii of each track and thickness of removed surface from each side of the detector due to chemical etching. Microdosimetric distributions of absorbed dose and dose equivalents are obtained from the LET spectrum. The absorbed dose and dose equivalent per incident proton obtained from the LET spectra are found to be about 12.5 and 8 times higher in 1H+9Be reaction than 1H+12C reaction. 相似文献
5.
E. Santner 《Journal of Radioanalytical and Nuclear Chemistry》1971,7(2):271-280
Three experimentally different methods for analysing silicon in steel by activation with fast neutrons are described. By bombardment of28Si with fast neutrons28Al is obtained after a (n, p) reaction.28Al emits a γ-radiation of 1.78 MeV. The difficulty lies in discriminating the 1.78 MeV peak out of the emitted radiation. The first method consists in determining the ratio of the 1.8 MeV peak to the 2.1 MeV peak of an activated iron sample. From this ratio one can deduct the contribution of28Al to the 1.8 MeV peak of a silicon containing sample. The other method of separation makes use of the different half-lives of the 1.78 MeV γ-rays from28Al and the 1.81 MeV γ-rays from56Mn. The direct separation of the peaks with a Ge(Li) detector is the third method. This paper illustrates the possibilities of activation analysis with fast neutrons. For this reason the values measured are compared with the results of chemical analyses. 相似文献
6.
The use, for analysis, of prompt gamma-rays excited by 5 MeV alpha-particles from the reactions19F(α,α′γ)19F,19F(α, nγ)22Na and19F(α, pγ)22NE, was studied. The precision of the analyses depended on the gamma-ray energy used for the measurement. Relative standard
deviations were ±1.8, ±0.9 and ±1.3% using the 110-, 197- or 1275 keV gamma-rays. The method was tested with N. I. M. standard
materials of calcium fluoride and fluorspar, and was used as a rapid method for the determination of fluorine in cements. 相似文献
7.
A. Arzumanov V. Batischev N. Berdinova A. Borissenko G. Chumikov N. Gorodisskaya A. Knyazev V. Koptev S. Lyssukhin Yu. Popov G. Sychikov D. Zheltov 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(1):215-218
Cyclotrons play an important role for production of carrier-free radioisotopes for various applications in the nuclear medicine, industry, ecology and science. Kazakhstan variable energy isochronous cyclotron, K = 50 MeV, is a 150 cm compact-pole 3 sector positive ion machine. It generates different beams of light ions: protons 6-30 MeV, deuterons 12.5-25 MeV, 3He-ions 18.5-62 MeV, alpha-particles 25-50 MeV. In the last years the cyclotron is rather intensively used for radioisotopes production to meet the needs of the Republic of Kazakhstan. The main users of radioisotope products are the Institutions of Healthcare Ministry and enterprises of oil-chemistry, metallurgy, mining, scientific institutes etc. In this submission a survey on radionuclides production including 201Tl, 67Ga, 57Co, 109Cd, 88Y, 85Sr is presented. Practically at all production stages (target preparation, extraction, purification and concentration of a product) original approaches were realized: (1) at target production by means of electrolysis the modes of reverse plating of the material for irradiation and technological layers were finalized, and at 67Ga production new extraction with better characteristics were used; that made the deeper purification from zinc, copper and iron possible. At the development of the technologies of the sealed sources production the following results were obtained: (1) 109Cd production for X-ray fluorescence analysis, and production of experimental samples for Mössbauer sources 57Co at rhodium and palladium backings. The tracers 237Pu, 88Y and 85Sr used for development of the set of methods for 239Pu, 240Pu, 90Sr and 241Am determination in the samples from Semipalatinsk Test Site were produced via nuclear reactions with alpha-particles on 235U and protons on 88Sr, 85Rb targets. Produced radiopharmaceutical preparations 201Tl chloride and 67Ga citrate are supplied to medical centers of Almaty. 相似文献
8.
A. I. Vilensky V. V. Berezkin V. D. Sobolev K. G. Sabbatovsky Yu. K. Kochnev S. V. Vlasov B. V. Mchedlishvili 《Colloid Journal》2009,71(4):470-473
The etching of latent tracks and pore formation in track membranes are studied. It is shown that the incorporation of K+ and Ba2+ ions into alkaline solutions accelerates the etching of poly(ethylene terephthalate) (PET) and latent tracks in it. The etching is accelerated due to a decrease in the negative surface charge of PET surface and the pores in track membranes. Isoelectric points are determined for PET and polyimide track membranes and it is established that they depend on pore diameter. As the pore diameter is enlarged from 30 to 70 nm, the magnitude of the negative surface charge rises seemingly due to the increase in the concentration of carboxyl groups on the pore surface. It is assumed that this effect is due to either a high mobility of carboxyl groups in a gel, which is formed on pore walls as a result of etching latent tracks, or a displacement of the slipping plane caused by a decrease in the thickness of the gel layer. 相似文献
9.
M. Bonardi C. Birattari M. Gallorini F. Groppi D. Arginelli L. Gini 《Journal of Radioanalytical and Nuclear Chemistry》1998,236(1-2):159-164
The increasing concentration of Pt, Pd and Rh in the environment is mainly due to the release of these elements from the catalytic
converters of the motorvehicles. This situation makes it necessary to carry out metallotoxicological experiments on both cell
cultures and laboratory animals, in order to assess their impact on living organisms after a Long Term and Low Level Exposure
(LLE). Both nuclear reactionsnatIr(p,xn) andnatOs(α,xn) were investigated in the energy range up to 45 MeV for protons and 38 MeV for alpha-particles, in order to optimize
the irradiation parameters for the production of188,189,191Pt. Several sets of thin- and thick-target excitation functions were determined experimentally by cyclotron irradiation at
both Milano and Ispra cyclotrons. This paper reports the irradiation parameters studied and adopted and two radiochemical
procedures for the separation of radio-Pt from an Os target, as well as from ruthenium, iridium and gold impurities. These
procedures were used to obtain very high specific activity Pt radionuclides in No Carrier Added (NCA) form. Radionuclidic,
radiochemical and chemical purity measurements were carred out by the use of several techniques like ψ-spectrometry, ion-exchange
radio-chromatography, atomic absorption spectrometry and neutron activation analysis. 相似文献
10.
Radiofrequency-discharge plasma treatment of heavy ion-irradiated poly(ethylene terephthalate) films
L. I. Kravets S. N. Dmitriev V. V. Sleptsov V. M. Elinson V. V. Potryasai O. L. Orelovich 《High Energy Chemistry》2000,34(2):116-121
The effects of treatment in a radiofrequency (RF) discharge plasma on the rate of chemical etching of the tracks made by xenon
ions (with an energy of ~1 MeV/nucleon) in poly(ethylene terephthalate) (PETP) films were investigated. The influence of plasma
treatment conditions on the structure and properties of nuclear track membranes formed by etching was studied. It was found
that the RF plasma treatment of heavy ion-bombarded PETP films leads to a decrease in etchability of both tracks and the starting
polymer matrix. The changes in track and matrix etchability due to crosslinking of the polymer surface layer were shown to
be responsible for the asymmetry of the track membrane structure. 相似文献
11.
《Radiation Physics and Chemistry》1999,53(4):377-384
Uranium and thorium contents in different layers of an archaeological site have been determined by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD) and calculating the probabilities for α-particles emitted by the uranium and thorium series to reach and be registered on the SSNTD films. A new method has been developed based on calculating the self-absorption coefficient of the gamma-photons emitted by the uranium (238U), thorium (232Th) and their corresponding decay products as well as the potassium-40 (40K) isotope for evaluating the annual absorbed gamma dose rates in the considered material samples. Results obtained have been compared with data obtained by using the TL dosimetry and Bell's (Bell, 1979) methods. Ceramic samples belonging to the studied archaeological site have been dated. 相似文献
12.
A non-destructive method for the analysis of the silver to silver plus copper ratio in coins using 14 MeV neutron activation analysis has been studied. The mass of silver to the mass of copper is obtained by measuring the 0.511 MeV annihilation radiation emitted by64Cu and106Ag at two separate times after irradiation. A series of British silver three-penny pieces dated 1891–1941 were analysed and agreed well with the mint assay. The interference from the presence of zinc in some coins was investigated. 相似文献
13.
Hakim Mazrou Zahir Idiri Tassadit Sidahmed Malika Allab 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(2):253-263
A new approach has been suggested to establish reliable response matrix of a CRNA Bonner Sphere Spectrometer equipped with
a high efficiency 10 mm diameter × 2 mm thick 6LiI (Eu) scintillation detector from thermal neutron energy up to 20 MeV. It combines the experimental response functions
obtained using a continuous neutron spectrum emitted from an 241Am-Be neutron source of known emission, with those obtained by Monte-Carlo (MC) calculations. Sensitivity analysis has been
performed to check the influence of pertinent parameters on the MC computed detector response. The parameters of interest
are the density of polyethylene moderators, the cross section library used in MCNP5 and two computing models depending on
the interactions of the neutrons in the detector. The calculated responses of the spectrometer to the 241Am-Be neutron source showed discrepancies depending on the sphere diameter when compared to our measured responses. However,
this difference was smaller compared with the experiments available in the literature. The enhancement achieved in the present
study is partly due to improved modeling in the MC calculations. To correct for the differences observed, a fitting factor
has been deduced for each sphere diameter and used to adjust the MC responses to the experimental ones. The obtained results
were subsequently compared to the experimental data of GSF-G spheres system obtained for a typical 4 mm diameter × 4 mm thick
6LiI scintillator for four ISO-8529 selected neutron energies (144.0 keV, 565 keV, 2.5 and 14.8 MeV). The present responses
were similar in shape but higher, in absolute values, by about two and half times for all spheres owing essentially to the
increase in active part of the detector. Finally, the CRNA-BSS response matrix containing 48 energy points from 0.01 eV to
20 MeV for 22 sphere diameters with a mean polyethylene density of 0.944 g/cm3 was constructed by applying a spline interpolation method. The released response matrix was then compared to data available
in the literature evaluated by Monte-Carlo calculations for a 4 mm × 4 mm 6LiI crystal scintillator. The obtained response matrix is intended for radiation protection applications at CRNA. 相似文献
14.
M. A. Misdaq H. Ezzahery J. Lamine 《Journal of Radioanalytical and Nuclear Chemistry》2002,252(1):67-74
A new Monte Carlo computer code was developed for determining the detection efficiencies of the CR-39 and LR-115 II solid state nuclear track detectors (SSNTD) for a-particles emitted by radon (222Rn) and thoron (220Rn) series inside the atmosphere of dwelling rooms. Alpha-activities due to radon, thoron and their decay products, were evaluated for the determination of the detection efficiencies of the SSNTD utilized for the emitted a-particles by measuring the corresponding track densities. The influence of the ventilation rate and building material on the concentration of radon, thoron and their progenies was investigated. Equilibrium factors between radon and its progeny and between thoron and its daughters have been evaluated in the air of the rooms. 相似文献
15.
J. Planinić 《Journal of Radioanalytical and Nuclear Chemistry》1993,175(2):95-101
Statistical errors of the track etching method were investigated by using the LR-115 nuclear track detector and visual microscopic counting. In the experiment, four persons counted tracks of the same detector and the analysis of variance was applied to the respective means and standard deviations. Another experiment was performed with ten detectors exposed to air in the same room; after standard etching and counting, the relative error of the detector track density was obtained as 11.2%. Taking into account the errors of the detector sensitivity coefficient and background, the total relative error of the track etching method was 19.5% in case of measurements of the indoor radon concentration of 8.2 Bq m–3. 相似文献
16.
S. Yegnasubramanian J. W. Mitchell 《Journal of Radioanalytical and Nuclear Chemistry》1987,110(1):235-243
The distribution of nitrogen in plasma deposited silicon nitride films and in commercially produced, hot-pressed bulk material has been determined by the nuclear (proton) track image analysis technique. The nuclear track technique is shown to have the unique capability of sampling large areas (cm2) while providing distribution information on the micro scale (100 m2). Nitrogen over the range of 2 to 40% is determined quantitatively. Spatial distribution and topographical maps are plotted. The overall composition of the material is established by 14 MeV NAA through the determinations of silicon, nitrogen, and oxygen. An application in the micro electronic industry is described. 相似文献
17.
Rahim Khabaz 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):5-12
In present work, an alternative irradiation system based on a symmetric cylindrical tank filled with a moderator containing hydrogen, which was equipped with a NaI(Tl) scintillation detector, was proposed for using in determination of neutron flux. This irradiation system was designed by MCNP4C code, with considering a 241Am–Be neutron source in several volumes and different materials. When the neutron is captured by hydrogen, a 2.22 MeV prompt gamma-ray is emitted. The gamma pulse-height spectrum shows a photo-peak around 2.22 MeV whose net area is proportional to the total emission rate of neutron. The simulation result showed that a cylindrical tank with 110 cm diameter and height filled with water can be a suitable system for neutron source strength calibration. Furthermore, a proper two-layer shielding must be placed between the source and detector for preventing neutrons and gamma rays to directly enter the detector. 相似文献
18.
Thick-target yield of γ-rays emitted in the reactions14N(p,p′γ1)14N and15N(p,αγ1)12C were measured as a function of bombarding energy in order to select the conditions favoring the employment of these reactions
in nitrogen isotopic analysis. The applicability of these reactions in the determination of relative as well as absolute nitrogen
isotopic abundances was demonstrated at 4.3 MeV bombarding energy.
Supported in part by the International Atomic Energy Agency, Vienna, Austria. 相似文献
19.
A new α track method is proposed for the measurement of radon (222Rn) concentration in environmental levels. This involves collecting radon daughters on the surface of pilot lamp and detecting
α-particles emitted from the nuclides (218Po and214Po) by a detector (LR 115). The detection sensitivity of this method is 6 times greater than that of the conventional α track
method. 相似文献
20.
Alpha to spontaneous fission branching ratios of heavy actinides such as238Pu and240Pu in solution have been determined by solid state nuclear track detectors (SSNTDs). The detectors used in the present studies
are LR-115, CR-39 (DOP), Lexan polycarbonate and Tuffak polycarbonate. Before using Tuffak polycarbonate, a detailed and systematic
study on the registration and chemical etching characteristics of fission fragment tracks in this detector was also carried
out. The experimentally measured values of alpha to spontaneous fission ratios by this method are found to agree well with
the expected values. 相似文献