摘要:

The properties of a metal surface can be enhanced by implantation with noble gas ions. Implantation has its effect on the stress state of the material. In this work, SS304 stainless steel is implanted with Ne+SS304 bears the property of being easily transformable from the face centered cubic (bcc) phase to the body centered cubic (bcc) phase. Before the implantation the SS304 samples were stress free and completely of the fcc phase, after the implantation bcc phase material is present and the implanted layer is in a compressive stress state. By using a different approach towards glancing angle X-ray diffraction we were able to measure a depth profile of the bcc material and to measure the stresses in the 0.1 μm thick implanted layer.

ISSN:1042-0150    

DOI:10.1080/10420159408219972

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The influence of the surface on the shape of range distributions of ions implanted into solid matter was examined by TRIM computer simulations, with the intention to gain correction factors for analytic range codes (such as e.g. PRAL), as the latter ones yield informations about range distributions in infinite media only. It turns out that the surface influence is rather pronounced for low generalized energies e up to about 102. Here, ranges and range stragglings are modified by up to about 50%, depending on the characteristic kinematic factor of the examined system. Approximate fit formulae are given for this effect. The values of the third range profile moment, the skewness, are strongly modified by the surface influence in the WF = 10−'to 10’ regime in quite a complicated way. The forth moment (the kurtosis) is not modified markedly by the surface influence within its statistic accuracy. Finally, the backscattering yield is correlated with the ratio between the vacancies produced in an infinite and a finite medium, respectively, and with the corresponding ratio of range profile moments

ISSN:1042-0150    

DOI:10.1080/10420159408219973

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The energy loss measurements for O and Ti ions were done in a 2 μ mylar foil and A ions in carbon foil (75.5 μg/cm2). The choice of the mylar was due to its wide application in ERDA (Elastic Recoil Detection Analysis) experiments and thin windows for gaseous detectors. As a new approach, recoil ions produced in heavy ion scattering (ERDA) were utilised for (dE/dx)emeasurements. The energy loss thus measured for different energies of the secondary beam selected by changing the detection angle have been reported earlier by us. In the present work these experimental stopping powers are compared with values obtained using various theoretical models as well as semi emperical model and TRIM simulation code. LSS theory is used for low velocity case and Bethe formula for high velocity case. In the intermediate velocity region, suitable modifications of Bethe formula and Braggs rule for stopping power of compounds (Mylar) has been used and reasonable agreement obtained

ISSN:1042-0150    

DOI:10.1080/10420159408219974

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Irradiation of p and n type GaSb single crystals grown by Stockberger method was investigated using X-rays (20 or 30 Kev, 10 mA) and γ-rays (34 Krad/hr). Both electrical and optical properties were studied before and after irradiations. An attempt was also made to recover the radiation induced damages by thermal annealing at 450°C in presence of H2(5%) and Argon(95%). After both types of irradiation the carrier concentration increased for p-GaSb and decreased for n-GaSb due to creation of acceptor type defects in either cases. However, the resistivity increased and the mobility decreased for both the samples. After thermal annealing, the carrier concentration of the X-ray irradiated p-GaSb further increased due to complete or partial removal of interstitials while γ-ray irradiated one showed a recovery to the original value. The mobility of the X-ray irradiated p-type sample was recovered partly. For n-GaSb, the thermal annealing recovered the carrier concentration almost fully for both type of irradiations but the mobility recovery was only partial. The value of the absorption coefficient as a function of wavelength increased for p-GaSb but decreased for n-GaSb because of the change of carrier concentration. The absorption edge broadening due to irradiation was observed.

ISSN:1042-0150    

DOI:10.1080/10420159408219975

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Samples of pure single crystals of NaC1 and of a natural rock salt were simultaneously gamma-irradiated at an approximate constant dose rate (15 kGy/h) and a constant temperature (100°C) and for different lengths of time, resulting in integrated doses ranging from 0.02 to 44.6 MGy. Microstructural analysis showed that both incipient deformation structures and very advanced recovery structures develop during irradiation. This shows that gamma-irradiation does not only cause dislocations to develop, but also to migrate and interfere. It is also shown that Na-colloids do not only develop attached to dislocations, but migrate, accumulate and annihilate together with them. Microstructural criteria are established to distinguish between three different types of colloid-depleted areas that develop with increasing irradition: a) bleached areas produced by dislocation rearrangement and migration; b) bleached areas produced by diffusion along the dislocation rearrangements; and c) (in polycrystals) white areas produced by migration of wet (brine containing) high-angle boundaries.

ISSN:1042-0150    

DOI:10.1080/10420159408219976

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

ESR and thermoluminescence (TL) phenomena induced by X-irradiation of the samples with various compositions in the Rb, SO4-MgSo4and the Cs2SO4-MgSO4systems were investigated in terms of the reactivities and crystallographic properties. Rb2Mg2(SO4)3compound, which have a langbeinite structure, is formed in the Rb2SO4-MgSO4system. ‘Compound X', which is presumably of a langbeinite structure, is formed in the Cs2SO4-MgSO4system. The amount of Rb2Mg2(SO4)3compound formed in the Rb2SO4-MgSO4system, takes a maximum at the stoichiometric composition, while that of compound X in the Cs2SO4-MgSO4system takes a maximum at a composition richer with MgSO4than the stoichiometric composition. ESR signal intensity was dependent on the amount of Rb2Mg2(SO4)3compound and compound X. These results suggest that SO3−radicals are easily formed by electronic excitation in the langbeinite structure compound. A highly intensive TL resulted from the replacement of Rb+by a small amount of Mg2+, in the Rb2SO4-MgSO4system. No bright TL was, however, observed in all compositions in the Cs2SO4-MgSO4system. The results were discussed on the basis of the crystallinity of the mixed compounds formed in the Rb2SO4-MgSO4and the Cs2SO4-MgSO4systems.

ISSN:1042-0150    

DOI:10.1080/10420159408219977

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Lif:Mg, Cu, P polycrystal suffers a serious damage to its thermoluminescence (TL) sensitivity when exposed to high-level dose of60Co gamma rays. After an exposure up to 106Gy, the relative TL response of the peak (210°C) per unit absorbed dose is only 1.40 × 10−6as compared with that exposed to low dose. While the residual peak is eliminated by annealing at 400°C, the thermoluminescent sensitivity is about 14% of the original one for a test dose of 0.01 Gy. High temperature annealing procedures have been investigated to remove the influence of radiation damage on its sensitivity at low dose. Results show that after annealing at 600°C for 30 min, the TL sensitivity of the samples exposed to high-level dose can be restored. The procedure of thermal treatment is described in detail. A possible explanation for the recovery is discussed.

ISSN:1042-0150    

DOI:10.1080/10420159408219978

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159408219979

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effect of 250 keV H+ion irradiation on the critical temperature,Tc, and resistance of thin film YBa2Cu3O7-δspecimens with different initial values ofTcand approximately the same values of resistivity,p, was studied. The dependences ofon(Tcxandpo(100K)were the parameters before the irradiation) are linear and have the same slopes in the low dose range which confirms the theory of V. F. Elesin (Supercond., Phys. Chem. Technol. 4 (1991) 568).

ISSN:1042-0150    

DOI:10.1080/10420159408219980

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Gamma radiolytic decomposition of sodium and potassium nitrates dispersed in respective phosphate, sulfate and carbonate matrices has been studied over a wide absorbed dose range upto 300 kGy. Decomposition of nitrates increases with the concentration of the additive in the admixtures. G(NO−2) values, calculated on the basis of electron fraction of the nitrate decreases with the absorbed dose and with the increasing concentration (or mol %) of the nitrate. Thermoluminescence (TL) and Electron Spin Resonance (ESR) studies suggest the formation of radical species which may interact with NO−3causing enhancement in the decomposition process. A comparison of G-values for three additives suggests that the efficiency of the energy transfer decreases in the order PO3-4> CO2-3> SO2-4and depends on the nature and the concentration of the additive as well as the nature of cation/anion.

ISSN:1042-0150    

DOI:10.1080/10420159408219981

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor