X-ray irradiation-induced changes in Bayfol DPF 5023 polycarbonate

Samples from sheets of the polymeric material Bayfol DPF 5023 have been exposed to X-ray radiation in the dose range 100–2300 Gy. The modifications induced in Bayfol samples due to X-ray irradiation have been studied through different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, intrinsic viscosity, refractive index and color difference studies. The infrared spectroscopy indicated that crosslinking is the dominant mechanism at the dose range of 200–2300 Gy. The crosslinking reported by FTIR spectroscopy destroyed the degree of ordering in the Bayfol samples, as revealed by the XRD technique. Also, this crosslinking led to an increase in the value of intrinsic viscosity from 0.54 for the non-irradiated sample to 0.63 for the sample irradiated with 2300 Gy at 30 °C, indicating an increase in the average molecular mass. This was associated with an increase in the refractive index. Additionally, the non-irradiated Bayfol samples showed significant color sensitivity toward X-ray irradiation. This sensitivity appeared in the change of the blue color component of the non-irradiated Bayfol film to yellow after exposure to X-ray doses up to 2300 Gy. This is accompanied by a net increase in the darkness of the samples.     

Thermal,electrical and optical properties of proton-irradiated Makrofol DE 7-2 nuclear track detector

Samples from sheets of the polymeric material Makrofol DE 7-2 have been exposed to 1 MeV protons of fluences in the range 2.5×10¹³–5×10¹⁵ p/cm². The resultant effect of proton irradiation on the thermal properties of Makrofol has been investigated using thermogravimetric analysis and differential thermal analysis (DTA). The onset temperature of decomposition T _o and the activation energy of thermal decomposition E _a were calculated, and the results indicated that the Makrofol detector decomposes in one weight loss stage. Also, the proton irradiation in the fluence range 7.5×10¹³–5×10¹⁵ p/cm² led to a more compact structure of Makrofol polymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. The variation of transition temperatures with proton fluence has been determined using DTA. The Makrofol thermograms were characterized by the appearance of an endothermic peak due to the melting of the crystalline phase. The melting temperature of the polymer, T _m, was investigated to probe the crystalline domains of the polymer. At a fluence range of 7.5×10¹³–5×10¹⁵ p/cm², the defect generated destroys the crystalline structure, thus reducing the melting temperature. In addition, the V–I characteristics of the polymer samples were investigated. The electrical conductivity was decreased with the increasing proton fluence up to 5×10¹⁵ p/cm². Further, the refractive index, transmission of the samples and any color changes were studied. The color intensity Δ E was greatly increased with the increasing proton fluence and was accompanied by a significant increase in the red and yellow color components.     

Effect of electron beam irradiation on the structural,thermal and optical properties of poly(vinyl alcohol) thin film

Poly(vinyl alcohol) (PVA) polymer was prepared using the casting technique. The obtained PVA thin films have been irradiated with electron beam doses ranging from 20 to 300 kGy. The resultant effect of electron beam irradiation on the structural properties of PVA has been investigated using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), while the thermal properties have been investigated using thermo-gravimetric analysis and differential thermal analysis (DTA). The onset temperature of decomposition T ₀ and activation energy of thermal decomposition E _a were calculated, results indicate that the PVA thin film decomposes in one main weight loss stage. Also, the electron beam irradiation in dose range 95–210 kGy led to a more compact structure of the PVA polymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. The variation of transition temperatures with electron beam dose has been determined using DTA. The PVA thermograms were characterized by the appearance of an endothermic peak due to melting. In addition, the transmission of the PVA samples and any color changes were studied. The color intensity Δ E was greatly increased with increasing electron beam dose, and was accompanied by a significant increase in the blue color component.     

The effects of fast neutron irradiation on oxygen in Czochralski silicon

The effects of fast neutron irradiation on oxygen atoms in Czochralski silicon (CZ-Si) are investigated systemically by using Fourier transform infrared (FTIR) spectrometer and positron annihilation technique (PAT). Through isochronal annealing, it is found that the trend of variation in interstitial oxygen concentration ([O_i]) in fast neutrons irradiated CZ-Si fluctuates largely with temperature increasing, especially between 500 and 700℃. After the CZ-Si is annealed at 600℃, the V₄ appearing as three-dimensional vacancy clusters causes the formation of the molecule-like oxygen clusters, and more importantly these dimers with small binding energies (0.1--1.0eV) can diffuse into the Si lattices more easily than single oxygen atoms, thereby leading to the strong oxygen agglomerations. When the CZ-Si is annealed at temperature increasing up to 700℃, three-dimensional vacancy clusters disappear and the oxygen agglomerations decompose into single oxygen atoms (O) at interstitial sites. Results from FTIR spectrometer and PAT provide an insight into the nature of the [O_i] at temperatures between 500 and 700℃. It turns out that the large fluctuation of [O_i] after short-time annealing from 500 to 700℃ results from the transformation of fast neutron irradiation defects.     

Effect of gamma irradiation on the structural and optical properties of PVA/CdS nanocomposite films prepared by ex-situ technique

ABSTRACT

For a comprehensive understanding of the PVA/CdS nanocomposite properties, it is essential to select the suitable method for their preparation as well as elucidate the interfacial interactions, which still need support. CdS nanoparticles have been prepared by thermolysis method under the flow of nitrogen. Rietveld refinement of x-ray data shows that all the CdS samples have both cubic and hexagonal structures. Then PVA/CdS films were prepared by ex-situ technique. Samples from PVA/CdS nanocomposite have been irradiated with gamma doses in the range 10–120?kGy. The implanting of CdS NPs into PVA matrix was confirmed by XRD hand in hand with UV–vis and FTIR spectroscopic techniques. UV/VIS absorption spectra confirm the formation of hybridized film CdS/PVA nanocomposite with a refractive index in the range of 1.32–1.48 (at 500?nm). UV/VIS measurements were also used in calculating different optical parameters such as refractive index, extinction coefficient and optical band gap energy. Additionally, Tauc’s relation was used to determine the type of electronic transition. It is found that the gamma irradiation in the dose range 30-90?kGy led to a more compact structure of PVA/CdS nanocomposite and causes proper dispersion of CdS nanoparticles in the PVA matrix. This led to the formation of coordination reaction between OH of PVA and CdS nanoparticles, resulted in an increase in refractive index and the amorphous phase. Also, the gamma irradiation reduces the optical energy gap from 4.53 to 2.19?eV, and accompanied with an increase in the Urbach energy from 2.28 to 4.46?eV, at that dose range which could be attributed to the increase in structural disorder of the irradiated PVA/CdS nanocomposites due to crosslinking. Further, the color intensity ΔE, which is the color difference between the non-irradiated sample and the irradiated ones, was increased, from 0 to 10.8, with increasing the gamma dose, convoyed by an increase in the red and yellow color components.     

Proton-induced changes in Bayfol CR 1-4 nuclear track detector

Samples from the polymeric material Bayfol CR 1-4 have been exposed to 1 MeV protons with fluencies in the range 10¹¹–10¹⁴ ions/cm ². The resultant effect of proton irradiation on the thermal properties of Bayfol CR 1-4 has been investigated using thermo-gravimetric analysis (TGA). The onset temperature of decomposition T ₀ and activation energy of thermal decomposition E _a were calculated, results indicated that the Bayfol detector decomposes in one weight loss stage. In addition, the structural modifications in the proton-irradiated Bayfol samples have been studied as a function of fluence using X-ray diffraction and intrinsic viscosity of the liquid samples. Furthermore, the refractive index was measured for the non-irradiated and irradiated Bayfol samples. The results indicated that the degradation is the dominant mechanism in the fluence range 1×10¹¹–5×10¹⁴ ions/cm ². These results have been compared with those obtained in our previous work for Bayfol CR 6-2.     

Application of jacobi polynomial methods to the one-speed transport equation

The transport equations associated with radiation damage studies are often solved using expansions in Legendre polynomials. The radiation damage distribution functions which satisfy these equations may be sharply peaked in the forward direction, while the Legendre polynomials, as a set, are isotropic. This situation requires the use of many terms in the Legendre expansion in order to adequately represent the distribution functions. The Jacobi polynomials, on the other hand, can have strong peaking built into their associated weight function. To test the usefulness of the Jacobi polynomials we use them to solve the simple, one-speed, neutron transport equation. The results are then compared to the exact theory and to the results of applying Legendre methods to the same problem. This sample calculation demonstrates the advantage of the Jacobi polynomials in strongly non-isotropic situations.     

The interpretation of radiation damage experiments on gold

The paper shows that the conclusions drawn from recent experiments on electron irradiation of gold at about 100° K should be reversed, i.e. that these experiments speak against the free thermally activated migration of interstitials at the irradiation temperature. It is shown that this viewpoint is in agreement with several related experiments, which may all be interpreted by a dynamic propagation of crowdions over distances between 1000 Å and 2000 Å. At intermediate and high defect concentrations the dynamic propagation mechanism is suppressed.     

Effect of gamma-irradiation on the structural,optical and electrical properties of PEO/starch blend containing different concentrations of gold nanoparticles

ABSTRACT

Blend of polyethylene oxide (PEO)/starch (70/30 wt.%) filled with different amounts of gold nanoparticles (AuNPs) were prepared using the casting technique. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) techniques were used to investigate the structure of polymeric samples before and after exposing to gamma irradiation at different times. XRD showed a gradual decrease in intensity of crystalline peaks with increasing the gamma dose denotes a decrease in the amount of crystalline phase in the films, while the FTIR measurement shows induced changes in chemical structure assigned to the AuNPs amount and irradiation times. The optical energy gap values (E_g) for unirradiated and irradiated samples were calculated and interpreted. The differential scanning calorimetry (DSC) which showed the miscibility between the two components of the blend. The electrical conductivity (σ) measurement was showed increased in electrical conductivity after exposure to the gamma dose. The gold nanoparticles were used as nano?ller to improve the structural and electrical properties of polymeric samples. The results showed the Gamma irradiation significantly effect on the structural and electrical properties of PEO/starch blend.     

Effect of low dose neutron irradiation on the mechanical properties of an AIMgSi alloy

Abstract

An AlMgSi alloy prepared in two different conditions of age-hardening was neutron irradiated to fast fluences up to 2.5 × 10¹⁸n cm^?2 at 50°C. Postirradiation tensile and hardness tests were performed in the range from room temperature up to 350°C. The results show that the alloy in its soft and hard conditions exhibits a pronounced degree of irradiation-induced softening. The degree of softening is found to be dependent upon the ageing treatment given to the alloy before irradiation. The observed softening is suggested to be brought about by irradiation-induced dissolution of the age-hardening precipitates present before irradiation.     

Changes induced in structure and optical properties of PM-355 nuclear track detector due to laser irradiation

PM-355 is a class of polymeric solid-state nuclear track detectors which has a lot of applications in several radiation detection fields. Samples from sheets of PM-355 have been exposed to infrared (IR) laser fluences ranging from 1 to 12.8?J/cm². The effect of IR laser radiation on the structural properties of PM-355 has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The results indicate that the samples exhibit chain scission under the effect of laser irradiation up to 4.2?J/cm², thus producing free radicals that led to the formation of new bonds started and continued until 12.8?J/cm². This reduces the ordering structure, giving the PM-355 polymer more resilience. In addition, the laser irradiation at the fluence range 4.2–12.8?J/cm² led to a more compact structure of PM-355, which resulted in an improvement in its isotropic nature with an increase in Vickers hardness and refractive index. Further, the color changes due to laser irradiation were computed using the transmission data in the wavelength range of 370–780?nm. It is found that the color intensity, which is the color difference between the irradiated samples and the non-irradiated one, increases with increasing the laser fluence, largely depending on the proportions of the blue color component.     

Effect of neutron irradiation on optical spectra of α-Al2O3 and α-SiO2 single crystals

Using two crystal dielectrics (α-Al₂O₃ and α-SiO₂) as examples, the author studied the effect of large neutron-radiation doses on their optical spectra. The variation in IR spectra in the region of α-SiO₂ stretching and deformation vibrations is investigated; its relation to changes in the structure of the irradiated crystal is discussed. Institute of Nuclear Physics, Academy of Sciences of the Republic of Uzbekistan, Ulugbek Settlement, Tashkent, 702132. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 135–138, January–February, 1999.     

质子与中子辐照对电荷耦合器件暗信号参数的影响及其效应分析

对科学级电荷耦合器件(charge-coupled device, CCD)进行了质子和中子辐照试验及退火试验, 应用蒙特卡洛方法计算了质子和中子在CCD中的能量沉积, 分析了器件的辐射损伤机理. 仿真计算了N⁺埋层内沉积的位移损伤剂量, 辐照与退火试验过程中主要考察暗信号的变化规律. 研究结果显示, 质子与中子辐照均会引发暗信号退化, 其退化的规律与位移损伤剂量变化一致; 退火后, 质子辐照所致CCD暗信号大幅度恢复, 其体暗信号增加量占总暗信号增加量的比例最多为22%; 中子辐照引发的暗信号增长主要为体暗信号. 质子和中子在N⁺埋层产生相同位移损伤剂量的情况下, 两者导致的体暗信号增长量相同, 质子与中子辐照产生的体缺陷对体暗信号增长的贡献是同质的.     

Effect of polymer blend types and gamma radiation on the physico-chemical properties of polycarbonate

Samples from polycarbonate (PC) were classified into two main groups. The first group was blended with Abietic acid (Rosin) with different compositions, while the second group was blended with ethylene-vinyl acetate (EVA) copolymer with almost the same composition. A comparative study of the effect of both Rosin and EVA concentration on the thermal stability of PC has been investigated using thermogravimetric analysis. The results show that blending with Rosin causes the dominance of degradation. Samples from PC with 20% Rosin blend were irradiated with gamma at the dose of range 20–300?kGy. The resultant effect of gamma radiation on the structural properties of the 20% Rosin/ 80%PC blend has been investigated using Fourier Transform Infrared FTIR spectroscopy. The results indicate that degradation of the polymer blend dominates, thus increases the creation of hot free radicals that leads to the formation of color centers in PC. In addition, the transmission of the 20% Rosin/80%PC samples as well as color changes was studied. The color intensity ΔE was greatly increased with increasing the gamma dose up to 300?kGy, accompanied by a significant increase in the blue color component.     

Effect of swift heavy ion irradiation on thermal,optical and structural properties of poly vinylidene chloride

Poly vinylidene chloride (PVDC) irradiated with lithium (50 MeV), carbon (85 MeV), nickel (120 MeV) and silver ions (120 MeV) having fluence range of 1 × 10¹¹ ions/cm² to 3 × 10¹² ions/cm² have been studied using different techniques i.e. XRD (X-ray diffraction), FTIR (Fourier transform infrared), UV–Visible and TGA (thermo-gravimetric analysis). In XRD analysis, the intensity of diffraction peaks of PVDC irradiated with lithium ions was enhanced at lower fluence as compared to pristine. The shift in optical absorption edge in irradiated PVDC was correlated with the decrease in optical band gap energy. The distinguishable characteristic peaks were observed due to UV–Vis analysis, in lithium irradiated samples of PVDC at higher fluences. The % age decrease in optical band gap energy for the respective ions were 30.9%, 34.16%, 81.1%, 87.02% respectively. Formation of double carbon bonds and breaking of C–O and C–Cl bonds with the release of Cl in irradiated PVDC was observed in FTIR spectra. In Thermogravimetric analysis (TGA), the % age weight loss observed for irradiated samples with increase in ion fluence was lesser than the % age weight loss observed in pristine sample.     

The influence of fast neutron irradiation on the IR optical properties of NTD-Silicon

Optical IR measurements of NTD-Si are presented for different fast neutron doses. The exponential dependence of the divacancy concentration and the near-edge absorption as a function of fast neutron flux is reported. Silicon one-phonon absorption, caused by the irradiation, is also increasing with the rising percentage of fast neutrons in the flux     

Influence of 120 MeV S9+ ion irradiation on structural,optical and morphological properties of zirconium oxide thin films deposited by RF sputtering

The calibrated and controlled swift heavy ions (SHI) beam irradiation generate defects which can cause modifications in various properties of the materials such as structural, optical, magnetic, morphological, and chemical etc. The passage of ion through the target material causes the nuclear energy losses ($S_n$) and electronic energy losses ($S_e$). The $S_e$ dominates over $S_n$ in SHI irradiation. In the present study, ZrO₂ thin films were grown on silicon and glass substrate by using RF sputtering deposition technique. For the purpose of modifications induced by swift heavy ions, these films were irradiated by a 120 MeV S⁹⁺ ion beam of 1 pnA current, with varying ion fluences from 5E12 to 1E13 ions/cm², using the tandem accelerator at the Inter University Accelerator Center (IUAC), New Delhi, India. The X-ray diffraction (XRD) patterns confirmed the formation of monoclinic and tetragonal phases and it was observed that XRD peaks intensity increased up to the fluence of 5E12 ions/cm² followed by opposite behavior at higher fluences. Atomic force microscope (AFM) study revealed the increased surface roughness after SHI irradiation. In addition to it, the formation of electronic transition states in optical band gap region and enhancement of absorption edge was observed from UV-visible spectroscopy (UV-Vis) results due to which direct band gap energy value decreased from those of un-irradiated samples. Photoluminescence (PL) broad emission spectra were determined using the excitation wavelength at 290 nm with the prominent peak at 415 nm which can be ascribed to Zr vacancies due to band edge emission as a result of free-exciton recombination. Rutherford backscattering spectrometry (RBS) technique was used for depth profiling and elemental composition in zirconia thin films. The expected role of electronic energy loss during ion irradiation is to modify the properties of the material has been discussed.     

Effect of proton irradiation on the physical properties of PC/PBT blends

Samples from polycarbonate/poly (butylene terephthalate) (PC/PBT) blends film have been irradiated using different fluences (1?×?10¹⁵– 5?×?10¹⁷ H⁺/cm²) of 1?MeV protons at the University of Surrey Ion Beam Center, UK. The structural modi?cations in the proton irradiated samples have been studied as a function of fluence using different characterization techniques such as X-ray diffraction and UV spectroscopy. The results indicate that the proton irradiation reduces the optical energy gap that could be attributed to the increase in structural disorder of the irradiated samples due to crosslinking. Furthermore, the color intensity ΔE, which is the color difference between the non-irradiated sample and those irradiated with different proton fluences, increased with increasing the proton fluence up to 5?×?10¹⁷ H^+/cm², convoyed by an increase in the red and yellow color components. In addition, the resultant effect of proton irradiation on the thermal properties of the PC/PBT samples has been investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It is found that the PC/PBT decomposes in one weight loss stage. Also, the variation of transition temperatures with proton fluence has been determined using DSC. The PC/PBT thermograms were characterized by the appearance of two endothermic peaks due to the glass transition and melting temperatures. The melting temperature of the polymer, T_m, was investigated to probe the crystalline domains of the polymer, since the proton irradiation destroys the crystalline structure so reducing the melting temperature.     

Modification of structural,optical, thermal and mechanical properties of KDP crystals on the addition of Ni

Nonlinear optical materials are acquiring a new significance day by day with the advent of a large number of devices utilizing solid state laser sources. Owing to this technological application KDP having superior nonlinear optical property has been exploited for various applications. KDP crystals were grown from aqueous solutions added with Ni²⁺. SHG studies confirm that the title exhibits NLO property. The influence of doping Ni²⁺ on the structural, optical, thermal, NLO and mechanical properties has been studied in this present investigation. It is observed that addition of Ni²⁺ improves the optical, thermal and mechanical properties of the crystal.