摘要:

High current, short length ion beam pulses appear to be a new alternative for surface property modification of solids, due to the combined effect of ion implantation with induced fast heating-cooling which this process presents. The repetitive pulsed nitrogen implantation (with a low energy plasma focus) of pure titanium with different pulse lengths (300 and 400 ns), and fluences per pulse ranging between 1.4 × 1014and 1 × 1015cm−2, with total accumulated fluences between 7 × 1014and 1.6 × 1016showed a surface heating effect with important compositional and physical changes in the layers close to the surface.

ISSN:1042-0150    

DOI:10.1080/10420159408221048

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Mass spectrometry has been used as an analytical tool in determining the species and quantities of volatile reaction products generated during destruction of polymers by ion implantation. Specifically, one very important objective was to relate the radiation chemistry with the radiation physics of fundamental track formation.

ISSN:1042-0150    

DOI:10.1080/10420159408221049

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Rutherford backscattering (RBS) technique has been used to determine the range profiles of Ar+implanted into polymer LPPS ([(C6H5)8Si8O12]n) film at energies of 50, 70, 90, 100, 120, 150 and 170 keV. It is found that the range profiles are Gaussian, and the experimental projected ranges are in a good agreement with the theoretical values calculated by TRIM'89 code at energies below 120 keV. As for range straggling, the experimental values are higher than the prediction values. In addition, a variation in the implantation dose from 5 × 1015to 1 × 1017ions/cm2at 50 keV does not affect the projected range, but the range straggling increases with the increasing implanted dose. The results of the implantation of Ar+in polymer PVA ([C2H4O]n) and PAM ([C3H5ON]n) show that the implant Ar is released instantly during ion implantation.

ISSN:1042-0150    

DOI:10.1080/10420159408221050

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Iron samples were implanted at a fluence of 1017N+ions.cm−2with an energy of 50 keV. The beam current density was varied in the range 6–60 μA.cm−2as well as the quality of the vacuum in the implantation chamber. Implantations were performed at 150°C to favour the carburization process. Carbon and oxygen contaminations were controlled using nuclear backscattering spectrometry (NBS) with α particles of 5.7 MeV and 7.5 MeV respectively or by using Auger electron spectroscopy (AES). The depth profiles of implanted nitrogen were determined by the15N(p,αγ) nuclear reaction or by AES when15N or14N ions were implanted respectively. Implantation induced chemical phases were characterized using Mössbauer spectroscopy and electron diffraction.

ISSN:1042-0150    

DOI:10.1080/10420159408221051

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effect of fast neutron bombardment (2 Mev252Cf source) with fluence of 1.07 × 1010n/cm2on the linear thermal expansion of Li-β-alumina ceramics was studied. Two ceramic groups in which the contents of oxides of Li, Na, K as well as B increased at the expense of alumina were prepared. Induced defects in terms of X-ray diffraction analysis were discussed to assess the use and applicability of these ceramics in neutron dosimetry.

ISSN:1042-0150    

DOI:10.1080/10420159408221052

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The influence of neutron (ø = 107n/cm2.s) irradiation on the hardness and fracture strength of the amorphous alloy Ni40Fe6Co20Cr12Mo6B16is studied at room temperature. There is little influence up to the fluence of 2 × 1012n/cm2, however, hardening is observed at higher fluences. While the hardness continues to increase from the fluence 2 × 1012n/cm2to 4.3 × 1013n/cm2, the fracture strength attains a peak value at fluence of ≃1013n/cm2, however, is drastically reduced at higher fluences. The results are discussed in terms of radiation induced defects and consequent formation of clusters like (Fe, Ni)3B

ISSN:1042-0150    

DOI:10.1080/10420159408221053

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The local demands for an improved neutron dosimeter have been grown in recent years. This work outlines a design for a dosimeter to measure incident neutron doses with any energy (thermal, intermediate and fast). Moreover this study presents the effect of radiators and converters on the sensitivity of chemically etched CR-39 detectors, as well as the sensitivity of electrochemically etched detectors at different frequencies and applied voltages.

ISSN:1042-0150    

DOI:10.1080/10420159408221054

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Magnetic After-Effect measurements have been made in the temperature range 4–600K on both high-purity and carbon-charged, polycrystalline cobalt and on single-crystal cobalt samples following electron-irradiation at 30K with 3 MeV electrons to a dose of 1023m−2. Attention has been focussed on the relaxation spectra following anneal above 300K. In all irradiated samples, a strong reduction in the amplitude of the relaxation spectrum in the range 250–400K occurs during anneal in this temperature range; this is attributed to the migration of the Stage III defect. In the high-purity material, no low-temperature relaxation processes evolve during this anneal. In contrast, in impurity-doped samples, low-temperature peaks evolve which are attributed to the reorientation of complexes formed by the migrating Stage III defect being trapped at interstitial carbon and at substitutional impurities.

ISSN:1042-0150    

DOI:10.1080/10420159408221055

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Optical reflection spectra and their derivatives of Ar+ion (75 keV) bombarded single crystals of Si and GaAs, with fluence ranging from 5 × 1011-1 × 1015ions cm−2, have been investigated in the spectral region of interband optical transitions. The effect of ion-beam induced disorder on the interband transitions in the two categories of semiconductors (direct/indirect band gap) have been found to be quite different. This dissimilarity may be due to the different optical response of the intermediate microcrystalline component formed by ion-bombardment during the course of crystalline-to-amorphous transformation.

ISSN:1042-0150    

DOI:10.1080/10420159408221056

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Different damage effects are observed in KDP and ADP when irradiated with light and heavy ion beams. Color centres stable up to 240 K are observed in both compounds irradiated with beams of 22 MeV2H+and fluences below 1 × 1016ions/cm2; a tentative mechanism for their generation is given. For fluences between 1 × 1016and 2 × 1016ions/cm2no further damage is observed in KDP; but ADP crystals show a light color stable up to the melting point and for higher fluences they appear white and opaque: X-ray diffraction patterns show no amorphization; a broad band due to electronic excitations, besides the characteristic Raman spectra is observed. No spontaneous cleavage was ever observed.

ISSN:1042-0150    

DOI:10.1080/10420159408221057

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor