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2009, Indian Journal of Physics
The energy loss of Li, C and O ions in polypropylene absorber foils has been measured using 15 UD Pelletron Accelerator facility at Inter University Accelerator Centre (IUAC), New Delhi, India. The actual experiment has been performed in low flux chamber attached to the General Purpose Scattering Chamber (GPSC). These experimental energy loss values have been compared with the computed values based on various empirical/semi-empirical formulations. Some interesting trends have been observed.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008
The energy loss and straggling in LR-115 and Kapton polymeric foils for Li, C, O and Si ions in the energy range $1.0-6.5 MeV/u have been measured, utilizing 15 UD Pelletron accelerator facility available at Inter University Accelerator Centre (IUAC), New Delhi, India. The measured energy loss and straggling values have been compared with the corresponding computed values adopting some widely used energy loss and straggling formulations. The aim of such a comparison is to check the reliability and validity of the existing energy loss and straggling formulations.
Experimental stopping data of, 63 Cu, 28 Si and 27 Al heavy ions in thin Polyvinylchloride (H 3 C 2 Cl 1) foil have been obtained over the 0.045–0.50 MeV/nucleon energy range. The measured energy losses were carried out by Heavy Ion Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with time of flight (ToF) spectrometer. A continuous stopping power data obtained in this work are well fitted by our proposed semi-empirical formula and the results are compared to those calculated by LSS formula or generated by SRIM-2013 and MSTAR predictions. Calculations using our formula agree well with the obtained experimental stopping powers, while the LSS formula underestimates the experimental data in the whole investigated energy range. In this work a simple expression for electronic stopping power of heavy ions at low energy in solid targets is introduced. This formula is based on the Firsov and Lindhard–Sharff stopping power models with a small modification made to the original expression, by incorporating the effective charge of moving ions concept and with exponential fit function.
Radiation Measurements, 2008
A particular brand of common polymer film has been found to have a high detection threshold value of Z/ , when used as a solid state nuclear track detector to detect energetic ion beams. From the infra-red absorption spectrum the film was identified to be polyethylene terephthalate (PET). Elemental analysis indicated the chemical formula of the polymer to be (C 5 H 4 O 2) n , which is also the same as that for PET. The charge response of this PET detector to light nuclei viz 16 O-ions has been studied using 53.6 MeV 16 O-ions from IUAC, New Delhi, India, using the air gap between the flange of the beam pipe and the detector as the energy degrader. The charge response for this PET detector has also been studied for heavy nuclei viz 238 U using 11.1 MeV/n U-ion beam from GSI, Darmstadt, Germany, with aluminium foils of different thickness to degrade the incident energy to several values. The charge response parameter V t /V g has been plotted against the z/ of incident ions in the PET detector as part of a program to calibrate this detector so that it can be used to identify rare cosmic ray events.
Radiation Measurements, 2001
Heavy ion range and energy-loss data provide useful information for designing several nuclear physics experiments where the polymers employed ÿnd their use as absorber, in chamber windows and target backings. In the present work, the range and energy-loss rate of 118 MeV 28 Si in LR-115 (cellulose nitrate) and polypropylene (PP) have been calculated by track technique where polyallyldiglycol carbonate was used as a backing detector. The mean range of 28 Si in LR-115 has been calculated to be 59:4 ± 2 m and that in PP is calculated to be 74:9 ± 2 m. The experimentally evaluated range values are in agreement with the theoretical range values derived from some computer codes. The Bragg peak has also been obtained at 1:1 MeV=nucleon for 28 Si in both LR-115 and PP.
2010
Some photon energy absorption parameters viz. mass energy absorption coefficient (l/q) en , photon energy absorption effective atomic number (Z PEA), electron density (N e) and KERMA relative to air has been computed in the energy range from 1 keV to 20 MeV for some polymers such as nylon, polyacrylo-nitrile, poly-methyl-acrylate, poly-vinyl-chloride, polystyrene , synthetic rubber and poly-tetrafluro-ethylene. The dependence of different parameters on incident photon energy and chemical composition of the selected polymers has been studied .
Radiation Effects and Defects in Solids, 2017
Mass attenuation coefficients (µ m), total atomic cross-sections (σ t), molar extinction coefficients (ε), electronic cross-sections (σ e), effective atomic numbers (Z eff) and electron densities (N eff) have been computed for few nylons that are polymers, namely, nylon 6 (C 6 H 11 ON), nylon 1,1 (C 11 H 21 ON), nylon 6,6 (C 12 H 22 O 2 N 2), nylon 6,9 (C 15 H 28 O 2 N 2), nylon 6,10 (C 16 H 30 O 2 N 2) and nylon 6,12 (C 18 H 34 O 2 N 2) using narrow beam good geometry setup. In the present investigation, radio-nuclides 57 C O , 133 Ba, 137 Cs, Co 57 , Ba 133 , Cs 137 , Na 22 , Mn 54 and Co 60 emitting energies 122, 356, 511, 662, 840, 1170, 1275 and 1330 keV have been counted by a NaI (Tl) detector coupled with the 8 K multichannel analyzer. Values of µ m , σ t and σ e decrease with increasing energy of gamma photons due to the dominance of Compton scattering in the selected energy range. Effective atomic numbers of chosen samples tend to be almost constant as a function of energy. It is clearly observed from the computed results that the among the chosen samples nylon 1,1 has good absorption capability of gamma photons in the low energy region. An attempt has been made to investigate the new gamma-ray-shielding materials that can be used at a large scale and that will be available at low cost.
Journal of Applied Physics, 2011
We have calculated the inelastic mean free path, stopping power, and energy-loss straggling of swift electron, proton, and a-particle beams in a broad incident energy range in four organic polymers: poly(methyl methacrylate) (PMMA), Kapton, polyacetylene (PA), and poly(2-vinylpyridine) (P2VP). These calculations have been done through a suitable description of their optical properties and its extension into the whole momentum and energy transfer excitation spectrum. For electrons, we take into account the exchange effect between the projectile and the target electrons, while the charge-state fractions have been considered for ions. Our results are compared with other models and with the available experimental data. An excellent agreement with experimental data is obtained in the case of proton and a-particle beams in Kapton and a reasonably good agreement has been achieved for electron beams in PMMA, Kapton, and PA. We have parameterized by means of simple analytical expressions our results for electron beams interacting with these four polymers, which can be easily implemented in Monte Carlo calculations. V
Heavy ion range and energy-loss data provide useful information for designing several nuclear physics experiments where the polymers employed ÿnd their use as absorber, in chamber windows and target backings. In the present work, the range and energy-loss rate of 118 MeV 28 Si in LR-115 (cellulose nitrate) and polypropylene (PP) have been calculated by track technique where polyallyldiglycol carbonate was used as a backing detector. The mean range of 28 Si in LR-115 has been calculated to be 59:4 ± 2 m and that in PP is calculated to be 74:9 ± 2 m. The experimentally evaluated range values are in agreement with the theoretical range values derived from some computer codes. The Bragg peak has also been obtained at 1:1 MeV=nucleon for 28 Si in both LR-115 and PP.
heavy ions in thin polymeric Formvar foil. The heavy ion elastic recoil detection analysis (HIERDA) technique coupled with time of flight (ToF) spectrometer was used. The aim of such a study is to check the reliability and accuracy of the existing energy loss straggling formulations. a b s t r a c t The energy-loss straggling of 28 Si, 27 Al, 24 Mg, 19 F, 16 O and 12 C partially stripped heavy ions has been determined in Formvar polymeric thin foil over a continuous range of energies 0.1-0.6 MeV/u, by using a powerful method based on the combination of Heavy Ion-Elastic Recoil Detection Analysis (HI-ERDA) technique and Time of Flight (ToF) spectrometer. The obtained energy loss straggling values have been analyzed and compared with the corresponding computed values adopting some widely used energy loss straggling formulations such as, Bohr, Bethe-Livingston and Yang formulas. The aim of such a comparison is to check the reliability and accuracy of the existing energy loss straggling formulations. The experimental results of energy loss straggling of all ions are found to be significantly greater than those predicted by the theories. These differences can be attributed to the charge exchange straggling. This effect has to be taken into account in order to explain the obtained results.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1984
In order to understand the multiply peaked structure of the energy loss spectra of low-velocity ions transmitted through thin polycrystalline foils we have carried out a model calculation based upon the idea that the low-loss peaks are due to axially channeled ions. It is assumed that the incident beam, upon striking the target, splits into a channeled and a random component. The emerging ions are described by appropriate angular distributions. The model predicts that the channeled-to-random intensity ratio in the energy loss spectra decreases with increasing ion energy as E-'. This is in reasonable agreement with experimental observations for 100-600 keV N transmitted through an Au foil with a (111) fibre texture. The calculations suggest a characteristic width of the texture of 5" to 8".
Radiation Measurements, 1997
The experimental results on the characterization of three polymeric solids in terms of energy-loss of 20-80 MeV t2C ions m Kapton, Hostaphan and Makrofol-N have been presented and compared with theoretical values.
Radiation Effects and Defects in Solids, 2001
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Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1991
Measurements of the transmitted energy straggling and energy loss are made for 7 and 14 MeV hydrogen, 21 and 28 MeV lithium and 42 and 49 MeV carbon ion beams incident on C, Al, Ti, Ni, Ag, W and Au foils using a silicon surface barrier detector. Film thicknesses ranged from a few to hundreds of microns. The energy and Z, dependence of the stopping power is investigated for each ion species. The experimental straggling widths are plotted as a function of the energy loss and compared to theoretical predictions.
Physical Review A, 2009
The statistical fluctuations in energy loss have been measured for O, Si, and S ions, in varying thicknesses of polyethylene naphthalate ͓PEN, or ͑C 7 H 5 O 2 ͔͒ polymeric foils. The measurements have been performed in the fractional energy-loss limits ⌬E / E ϳ 5-90 %. These fluctuations have been found to be enhanced with an increase in ⌬E / E. Such a behavior has been reproduced by Bethe-Livingston formulation after modifying it suitably.
Research Papers Faculty of Materials Science and Technology Slovak University of Technology, 2018
Exact determination of energy loss of ion in materials is still a non-trivial task because of relatively complicated changes of the ion`s stopping power S(E) during transport of the probing ion inside the material structure. Energy loss of ion in the material structure always depends on the current value of continually decreasing energy of the ion, indeed. A purely theoretical approach can be applied to the energy loss calculation in some typical cases. Average energy loss of ion can be determined by means of the Bethe-Bloch analytical theory (1-6) (in high velocity region) and the Lindhard-Scharff-Schiøtt (LSS) theory (7-10) (in low velocity region). Currently, there is no acceptable exact theory to determine the energy loss of ion in intermediate-velocity region (11) and experimental data must be used in that case. Basically, only a finite number of discrete experimental data is always available. Therefore, if the problem how much energy the projectile ion loses in a certain dista...
Indian Journal of Physics, 2009
The samples of polypropylene (PP) have been irradiated with 120 MeV 64 Cu 9+ and 70 MeV 12 C 5+ ion beams, with the fluence ranging from 1 × 10 13 to 1 × 10 11 ions/-cm -2 . UV-VIS and FTIR techniques have been used to study the chemical and optical properties of these irradiated polymers. UV spectra revealed that the optical-gap energy decreases by 54 % with copper ion irradiation at the fluence of 1 × 10 13 ions/cm 2 , whereas at the same fluence, carbon beam decreases the optical-gap energy by 20%. FTIR analysis of ion irradiated samples revealed the presence of -OH, C = O and C = C bonds. Alkyne formation has been observed only in the case of copper ion irradiation.
Ion beam treatment studies have been carried out to investigate the potential for improvements in conductivity properties of the polymers Polytetra¯uroethylene (PTFE), Polyimide (PI), Polyethyleneterepthalate (PET) and Polypropylene (PP), after 2 MeV electron and 62 MeV proton irradiation. The shift in optical absorption edges as observed by UV±VIS spectra of the irradiated polymers has been correlated to the optical band-gap using TaucÕs expression. A decrease in the optical band-gap has been observed in irradiated PP and PTFE, but no considerable change was found for the optical band-gaps of PET and PI. Further AC conductivity measurements con®rmed an increase in conductivity in electron irradiated PP. Ó
Applied Radiation and Isotopes, 2010
The energy loss straggling for 5.486 MeV a-particles, from 241 Am source, in PP (C 3 H 6), PET (C 10 H 8 O 4) and KAPTON (C 22 H 10 O 5 N 2) polymeric foils was measured. These measured values were compared with the most commonly used Bohr, Lindhard & Scharff and Bethe-Livingston formulations with the aim to check the reliability of these formulations. Further, Bethe-Livingston formulation has been suitably modified to make it applicable for thicker targets.
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