摘要:

50–1500 keV range profiles of 3He are presented in about 30 solid elemental targets for a wide range of doses. Theoretical predictions are compared to experimental results in each case. The four moments of the distribution are given. The backscattering yields are also presented. In addition to our own results, some representative depth profiles from other authors are included.

ISSN:0033-7579    

DOI:10.1080/00337578708225333

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Depletion of carbon in Ultra High Molecular Weight Polyethylene (UHMW PE) as a result of its radiolysis due to 340 keV D+ ion implantation up to a fluence of 1.8 × 1016 cm-2, has been observed by using the same beam in the RBS mode. Prolonged vacuum aging of the irradiated sample at room temperature does not show any further carbon (C) depletion which suggests the formation of low molecular weight fragments only, escaping instantaneously out of the sample. This has been explained on the basis of crystalline structure of UHMW PE. Unexpectedly low (= 20%) C-depleltion even at such a high dose (1000 M Gy) is explained on the basis of possible recombination of the radiolytically broken C–C bonds in the lamellar lattice. The C-depletion profile deduced from the Rutherford Back Scattering (RBS) spectra is unexpectedly Gaussian-like.

ISSN:0033-7579    

DOI:10.1080/00337578708225334

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Radiation damage in zeolite-13X exposed to neutrons is studied with reference to its effect upon the Cs+ uptake capacity of the zeolite. Structural investigation is carried out by XRD, IR, ESR spectroscopy and thermal analysis. The observations indicate a slight expansion with minor changes in the Al, Si order of the zeolite framework upon prolonged n-exposure. A 2.8% loss in zeolite water is attributed to radiolysisviathe n- and accompanying γ-interactions with water molecules. No significant change either in diffusivity or in net uptake of Cs + is observed.

ISSN:0033-7579    

DOI:10.1080/00337578708225335

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The lattice positions of Yb in Si have been reinvestigated by the planar channeling method. Our results show that the “Yb-sites” proposed by Andersenet al.are only occupied with 50%, the other half being located at the tetrahedral interstitial sites.

ISSN:0033-7579    

DOI:10.1080/00337578708225336

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The error is calculated when it arises in a transmission type experiment, where the stopping cross-section is determined only from a selected number of transmitted projectiles. We describe an experiment where this error is smallest: the target is evaporated onto a surface barrier detector, hence we measure almost in a2πgeometry. By this method the stopping cross-section of gold for hydrogen ions is determined between 35 keV/u and 500 keV/u relative to that at 500 keV/u. The following corrections are applied to the data: (i) due to the nonlinearity of the detector system, (ii) due to multiple scattering, and (iii) due to nuclear energy loss. The results show good agreement to earlier data of our group. The discrepancy to the tabulated values of Andersen and Ziegler is discussed.

ISSN:0033-7579    

DOI:10.1080/00337578708225337

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In this paper the distribution of increment of specific electric resistivity resulting from implantation of fission fragments (FF) versus depth has been investigated by the method of electric resistivity. This distribution was compared with the concentration profile of fission fragments implanted into a specimen. It has been shown that these profiles were practically identical in FF deceleration zones. In addition, insignificant increase of specific electric resistivity on depths essentially longer than FF run has been determined. This phenomenon was connected with the possibility of radiation defect formation at large distances. Annealing curves of specific electric resistivity in specimens, irradiated by neutron and mixed radiation (neutrons + FF) have been plotted. It has been observed that additional fission radiation led as to low so to high temperature defect formation in comparison with pure neutron irradiation.

ISSN:0033-7579    

DOI:10.1080/00337578708225338

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A theory has been developed of diffraction of soft X-ray photons and cold neutrons on a superlattice formed by voids in crystals. It is shown that for gamma-quanta and thermal neutrons, incident at a sufficiently small angle to the planes or axes of the superlattice, the effect of particle channeling becomes possible. Within the framework of the susceptibility, averaged over the planes or axes of the superlattice, a theory of channeling of neutral particles has been worked out.

ISSN:0033-7579    

DOI:10.1080/00337578708225339

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Diamond, Si and Ge powders were irradiated by Ne, Ar, Kr and Xe (3 Mev) ions up to tluences ot ∼ 200 ions/nm2. As reported for fast-neutron irradiation, diamond undergoes structural damage with heavy ion bombardment. The (111) X-ray diffraction line was observed to broaden and shift toward lower angles; the lattice parameter expansions were correlated with the displacement damage component of the energy of the bombarding ions. The X-ray line shifts apparently approached asymptotically limiting values with increasing ion fluences (10–30 ion/nm2), consistent with a model involving dynamic equilibrium between production and radiation annealing of the defects. The saturation lattice parameter shifts increased with increasing ion mass. A volume increment per defect of (1.3 ± 0.2) × 10−3nm3was derived which is about 23% of the atomic volume.

ISSN:0033-7579    

DOI:10.1080/00337578708225340

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Formation of etchable tracks in a variety of glasses has been studied. Three new types of glass track detectors were prepared and tested for the detection of heavy charged particles. Extensive experimentation was carried out in order to (a) optimize the chemical compositions of these glasses for their use as track detectors, and (b) to determine Z- and Z/β-track registration threshold values of these and of other commonly available glass track detectors. It is expected that a knowledge of the threshold values of these glasses besides being useful in quantitative applications is expected to enhance our understanding of the mechanism of etchable latent damage trail formation in glassy media.

ISSN:0033-7579    

DOI:10.1080/00337578708225341

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The amount of argon trapped and various surface property changes produced by 750 eV argon ion bombardment of Si(111) are investigated using Auger electron spectroscopy, thermal desorption spectrometry and low-energy electron diffraction. Critical saturation doses and annealing temperatures are determined, indicating that the surface reaches damage saturation at lower doses and begins to reorder at lower temperatures than the underlying region.

ISSN:0033-7579    

DOI:10.1080/00337578708225342

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor