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1.
Abstract Radiation damage produced by short ranged (ranges 20–30 μm) charged particles (alpha particles and fission fragments) in thick plastic track detectors (thickness ≈ 150 μm) has been enlarged to produce “through” holes by using a combination of electrochemical and chemical etching processes. A series of experiments were conducted with a view to optimize the operating conditions required to produce through holes with most suitable profiles for a particular application at hand. This novel technique has been employed in producing thick nuclear track filters using fission fragments from U-235 fission and alpha particles from radon and its daughters. 相似文献
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核微孔过滤器是利用重离子辐照高分子材料后经化学蚀刻而制成的新型过滤介质,它具有真实的孔径和高选择过滤性能.本文讨论了核微孔过滤器的生产原理、方法、特性和应用. The nuclear track microfilter has a true pore size and high selectivity,which are produced by irradiating a variety of polymers such as PC, PET, Kapton and PVDF using heavy ions and subsequent etching with the appropriate etchant. The pore size and porosity of the nuclear trackmicrofilters can be preselected according to what is required, their properties as well as already tested or possible applications are discussed. 相似文献
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介绍了一种核径迹探测器CR-39塑料的特性,这种探测器对逞电粒子非常灵敏,它还具有稳定、透明等特点,可记录p、a粒子,裂变碎片和其他带电粒子,它是现有固体核径迹探测器中能量沉积密度探测阈最低的材料,介绍了CR-39对带电粒子的响应,给出了各种带电粒子的vT对限定能量损失(REL)的响应曲线,利用CR-39与转换屏的组合还可测定能量范围广的中子能谱,可作为方便的个人中子剂量计,介绍了CR-39在研究 相似文献
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Y. K. Vijay 《Indian Journal of Physics》2009,83(7):927-935
Swift heavy ion irradiation produces damage in polymers in the form of latent tracks. Latent tracks can be enlarged by etching
it in a suitable etchant and thus nuclear track etch membrane can be formed for gas permeation / purification in particular
for hydrogen where the molecular size is very small. By applying suitable and controlled etching conditions well defined tracks
can be formed for specific applications of the membranes. After etching gas permeation method is used for characterizing the
tracks. In the present work polycarbonate (PC) of various thickness were irradiated with energetic ion beam at Inter University
Accelerator Centre (IUAC), New Delhi. Nuclear tracks were modified by etching the PC in 6N NaOH at 60 (±1) °C from both sides
for different times to produce track etch membranes. At critical etch time the etched pits from both the sides meet a rapid
increase in gas permeation was observed. Permeability of hydrogen and carbon dioxide has been measured in samples etched for
different times. The latent tracks produced by SHI irradiation in the track etch membranes show enhancement of free volume
of the polymer. Nano filters are separation devices for the mixture of gases, different ions in the solution and isotopes
and isobars separations. The polymer thin films with controlled porosity finding it self as best choice. However, the permeability
and selectivity of these polymer based membrane filters are very important at the nano scale separation. The Swift Heavy Ion
(SHI) induced nuclear track etched polymeric films with controlled etching have been attempted and characterized as nano scale
filters.
相似文献
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Makrofol polycarbonate—one of the widely used materials for making nuclear track filters, has been studied for its transparency to light (Λ = 350 nm to 950 nm). Also the optical transmission and IR-spectroscopy results on the Makrofol foils, forming nuclear track filters by irradiating with 14 MeV/n 238U ions, with and without post-irradiation UV and γ-exposures, are presented. Studies have been extended to these filters to investigate the variation of percentage transmission with etch-time, pore diameter, at different values of Λ. 相似文献
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C.-D. Zhao G. Haase M. Heck M. Tufail P. Vater H. A. Khan 《Isotopes in environmental and health studies》2013,49(6):296-299
222Rn dissolved in drilling fluids of the KTB (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland) pilot hole has been determined using solid state nuclear track detector (SSNTD) technique:The α-sensitive SSNTD CR-39 was used to measure the a-activity of 222Rn. Well-defined conditions for Rn-measurements could be established by employing a mica nuclear track microfilter to separate the detector containing air volume from the volume containing the water. This technique has been applied to determine quantitatively the 222 Rn-concentration as a function of depth of the borehole down to 4000 m. 相似文献
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S. F. Boulyga N. Erdmann H. Funk M. K. Kievets E. M. Lomonosova A. Mansel N. Trautmann O. I. Yaroshevich I. V. Zhuk 《Radiation measurements》1997,28(1-6):349-352
The knowledge of the isotopic composition of man-made transuranium elements (TUE) in the environmental samples is of great interest because, on the basis of these data, statements about the origin of the TUE can be made. One of the most radiotoxic elements released during reactor accidents and nuclear weapons tests was plutonium with the alpha emitters 238Pu, 239Pu, 240Pu, 242Pu and the beta-emitter 241Pu which decays into 241Am. The determination of plutonium in “hot” particles from the Chernobyl reactor was accomplished by means of solid state nuclear track detectors registering the alpha particles and by alpha spectroscopy after chemical treatment. Furthermore, in order to perform a complete analysis of the isotopic composition one of the “hot” particles has been investigated by resonance ionization mass spectrometry which possesses an excellent sensitivity and a good isotopic resolution. 相似文献
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Application of high-power ultrasound to enhance fluid/solid particle separation processes 总被引:1,自引:0,他引:1
Riera-Franco de Sarabia E Gallego-Juarez JA Rodriguez-Corral G Elvira-Segura L Gonzalez-Gomez I 《Ultrasonics》2000,38(1-8):642-646
The separation of fine particles from gases or liquids is a topic of permanent industrial attention. The use of ultrasonic energy to assist conventional separation techniques seems to be very promising. The adequate applications of high-intensity ultrasonic fields may contribute to improve the efficiency and capacity of the separation methods presently used. The specific mechanisms to ultrasonically enhance separation processes basically depend on the medium to be treated. In gas suspensions, where very fine particles have to be removed, ultrasonic action involves agglomeration of particles in order to increase their size and, consequently, to improve collection efficiency of conventional filters. In liquid suspensions, agglomeration is, in general, less efficient than in gases. Nevertheless, the ultrasonic energy is useful to dewater fine-particle high-concentration suspensions such as slurries and sludges. This paper deals with the application of acoustic energy to assist fluid/solid separation processes in gas and liquid suspensions and presents some theoretical and experimental results in specific applications. 相似文献
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Á. Н. Нuкоëаеɞ Н. А. Коëокоëь÷оɞ Ã. А. Суëаáерu÷ýе Ã. А. Теɞýаδýс В. А. ×ухсuноɞ 《Isotopes in environmental and health studies》2013,49(11):417-421
Experimental results are presented to show that the registration of heavy charged particles by solid state nuclear track detectors obeys more the Neyman type A distribution than the Poisson one as has been believed up to now. The theoretical background of this finding is given in detail. 相似文献
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I. V. Zhuk E. M. Lomonosova S. F. Boulyga A. P. Ipatov E. V. Kopets P. A. Pavlyukovich Z. V. Rytvinskaya 《Radiation measurements》1997,28(1-6):401-404
The method of solid state nuclear track detectors (SSNTD) has been used for the determination of uranium dioxide distribution in silicate compositions. The method of -radiography based on registration of - particles at the contact of SSNTD CR-39 with the specimen has been used here. An initial uranium dioxide applied for studying the dissolving process used as the standard. The results of the measurements of distribution of uranium dioxide concentration obtained with the help of this technique have been used for the estimation of diffusion and solubility of UO2 in silicate melts. 相似文献
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An on-line sensor to measure the density of a liquid or slurry, based on longitudinal wave reflection at the solid-fluid interface, has been developed by the staff at Pacific Northwest National Laboratory. The objective of this research is to employ shear wave reflection at the solid-fluid interface to provide an on-line measurement of viscosity as well. Both measurements are of great interest for process control in many industries. Shear wave reflection measurements were conducted for a variety of liquids. By analyzing multiple reflections within the solid (only 0.63 cm thick-similar to pipe wall thickness) we increased the sensitivity of the measurement. At the sixth echo, sensitivity was increased sufficiently and this echo was used for fluid interrogation. Shear wave propagation of ultrasound in liquids is dependent upon the viscosity and the shear modulus. The data are analyzed using the theory for light liquids (such as water and sugar water solutions) and also using the theory for highly viscous liquids (such as silicone oils). The results show that, for light liquids, the shear wave reflection measurements interrogate the viscosity. However, for highly viscous liquids, it is the shear wave modulus that dominates the shear wave reflection. Since the density is known, the shear wave velocity in the liquid can be determined from the shear wave modulus. The results show that shear wave velocities in silicone oils are very small and range from 315 to 2389 cm/s. Shear wave reflection measurements are perhaps the only way that shear wave velocity in liquids can be determined, because the shear waves in liquids are highly attenuated. These results show that, depending on the fluid characteristics, either the viscosity or the shear wave velocity can be used for process control. There are several novel features of this sensor: (1) The sensor can be mounted as part of the wall of a pipeline or tank or submerged in a tank. (2) The sensor is very compact and can be located within the process stream. (3) The sensor can interrogate and characterize very attenuative liquids or slurries because the sensor operation depends upon reflection at the interface between the solid and the fluid, rather than on transmission through a liquid. (4) The sensor performance is not affected by fluid flow rate, entrained air, or vibration. 相似文献
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对60AGeV^16O诱发乳胶核反应靶核碎片多重数分布及其关联进行了实验研究,并与FRITOF1.7加级联机制模型和DIUNUC2.0模型计算结果进行了比较/。 相似文献
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S. F. Boulyga A. I. Kievitskaja M. K. Kievets E. M. Lomonosova I. V. Zhuk O. I. Yaroshevich V. P. Perelygin R. Petrova R. Brandt P. Vater 《Radiation measurements》1999,31(1-6):191-196
Nuclear track radiography was applied to identify aerosol “hot” particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the -activity of “hot” particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (γ,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of “hot” particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by 235U, 239Pu and 241Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5×10−6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of “hot” particles. 相似文献
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The thickness of the removed layer of the LR-115-II solid state nuclear track detector during etching is measured directly
with a rather precise instrument. Dependence of bulk etching rate on temperature of the etching solution is investigated.
It has been found that the bulk etching rate is 3.2 μm/h at 60°C in 2.5 N NaOH of water solution. It is also found that the
track density in detectors exposed to soil samples increases linearly with the removed layer. 相似文献
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《Radiation measurements》2004,38(1):19-22
Studies on the presence of alpha emitting nuclides in the environment assume importance since they are found to be carcinogenic. This paper presents the first ever report of the measurements of alpha activity in drinking water in different places of South and North 24 Parganas of West Bengal where arsenic contamination is severe. The study has been made with solid state nuclear track detector which is one of the most commonly used detectors in the studies involving nuclear radiation. Our analysis provides positive evidence of presence of high alpha activity in drinking water of South and North 24 Parganas. 相似文献
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K. Amemiya H. Takahashi Y. Kajimoto M. Nakazawa H. Yanagie T. Hisa M. Eriguchi Y. Nakagawa T. Majima T. Kageji Y. Sakurai T. Kobayashi T. Konishi K. Hieda N. Yasuda K. Ogura 《Radiation measurements》2005,40(2-6):283-288
In radiation cancer therapies using energetic charged particles such as proton/heavy-ion therapy and boron neutron capture therapy (BNCT), studies on radiation-induced biological response at cellular level are important because the radiation damage from energetic charged particles is highly localized along their paths and the radiation sensitivity is quite different in each cellular organelle. In such studies the information on the position of charged particle impact in biological cells is necessary. A novel method for high-resolution nuclear track mapping in detailed cellular histology has been developed. In this technique, biological specimens mounted on CR-39 plates are exposed to energetic charged particles. The irradiated samples are exposed to UV, and then etched for a short time. Both etch pits of nuclear tracks and relief for transmission UV image of the specimen can be observed on the CR-39 surface with an atomic force microscope (AFM) at about 100 nm resolution. 相似文献
18.
N. A. Al-Liabi 《Isotopes in environmental and health studies》2013,49(1):56-57
The effects of storage temperatures on the track registration of CR-39 as a solid state nuclear track detectors have been investigated. The results show that the storage CR-39 detectors cause partial or complete removal of tracks depending on storaged time and temperatures. The bulk activation energy for CR-39 has been found to be 0.883 eV. 相似文献
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在银河宇宙射线中,400MeV/nucleon的铁离子通量相对来讲是较高的,400MeV/nucleon的铁离子对空间辐射引起的损伤和辐射剂量有重要的贡献.本文以Geant4为基础,对400MeV/nucleon Fe离子与物质相互作用后通过核反应过程产生的次级碎片进行模拟分析.对铁离子在水中产生的能量沉积和铁离子与水介质发生核反应后产生的次级碎片的能量沉积进行了模拟研究,得到了通过核反应过程产生次级粒子所导致的剂量贡献.
关键词:
能量沉积
剂量
碎片 相似文献