نتایج جستجو برای: cr 39

تعداد نتایج: 141644  

2013
M. Rafique M. H. Rathore

Extensive export quality reserves of granite, dolerite and marbles which are used for interior decorations as wall facing, paving floors, kitchen counter tops, etc., are available in Azad Kashmir. Since these stones contain radium in trace amounts, therefore, its use as a building material may be a potential source of indoor radon. In order to assess health hazards due to the use of these stone...

2008
D. S. Pressyanov

Recently, a method for long-term Rn measurements was proposed that combines the radon absorption ability of some polycarbonates, like Makrofol, with their track-etch properties. The method is independent of any particular Rn progeny behavior and the very first evaluation of this approach showed that its range of sensitivity covers practically the entire range of indoor Rn-concentrations. This m...

2006
M. Spurio

We report on the measurements of the total charge changing fragmentation cross sections in high-energy nucleus-nucleus collisions using Fe, Si and Pb incident ions. Several stacks of CR39 nuclear track detectors with different target combinations were exposed at normal incidence to high energy accelerator beams to integrated densities of about 2000 ions/cm. The nuclear track detector foils were...

Journal: :international journal of advanced biological and biomedical research 2015
mahdi jahangiri payman hejazi seyed mehdi hashemi abbass haghparast bardia hajizadeh

objective: using megavoltage photons generated by medical linear accelerator is a common modality for the treatment of malignant. the crucial problem for using photon beams >8mv is the photoneutron yields that increase the risk of secondary cancer that treated with high-energy photon beams. the contaminated neutrons produced in different components of the accelerator head and rely on many param...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389

نوترون¬ها دارای طیف های انرژی پیوسته و معمولا" بصورت مختلط با فوتون ها و سایر پرتوها موجود می باشند. بنابراین طراحی و ساخت آشکارسازی که بتواند به طیف وسیع انرژی نوترون پاسخ مناسبی داشته باشد بسیار دشوار و مسئله اساسی در بحث دزیمتری و آشکارسازی نوترون است. در این ت از یک پلیمر cr-39 به عنوان آشکارساز استفاده می¬شود. در این آشکارسازها نوترون¬ها به وسیله ردپای پروتون¬ها، اکسیژن ها و کربن¬های پس زد...

2010
S. Cockcroft C. D. Walton R. Zakaria

We report on the laser ablation of composite prismatic structures using a vacuum ultraviolet (VUV) 157 nm F2 laser. Polycarbonate and CR-39 substrates have been intentionally seeded with silver wires and silicon carbide whiskers respectively. The seed particles remain attached to the underlying substrate after laser ablation, forming composite silver-polycarbonate and silicon carbide-CR-39 inte...

2002
Giorgio Giacomelli

One of the primary aims of the MACRO detector at the Gran Sasso lab. (at an average depth of 3700 mwe) was the search in the penetrating cosmic radiation for the supermassive magnetic monopoles (MMs) predicted by Grand Unified Theories of the electroweak and strong interactions; the search was planned for a sensitivity level well below the Parker bound (∼ 10 cm s sr) and for a large range of ve...

Journal: :Laser and Particle Beams 2007

Journal: :iranian journal of radiation research 0
m. ghergherehchi department of nuclear engineering and physics, amirkabir university of technology, tehran, iran h. afarideh department of nuclear engineering and physics, amirkabir university of technology, tehran, iran m. ghanadi nuclear science and technology research institute, tehran, iran a. mohammadzadeh nuclear science and technology research institute, tehran, iran m. esmaeilnezhad nuclear science and technology research institute, tehran, iran

background: high and intermediate energy protons are not able to form a track in a solid state nuclear track detector (ssntd) directly. however, such tracks can be formed through secondary particles created during primary radiation nuclear reactions in a ssntd. materials and methods: the protons with primary energies of 9.6 and 30 mev available at the cyclotron accelerator with corresponding lo...

2017
Robert Katz

It is proposed that the “threshold for etchable track formation” in plastics is associated with the linear density of activated polymeric clusters along the path of an ion, in the “grain-count regime.” Existing data for CR-39 reveal a change in etching rate in the neighborhood of z/β having the value of about 15-20. We infer that this defines the transition from the grain count regime to the tr...

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