摘要:

The room-tempeterature neutron degradations of the minority carrier lifetimes in lithium-diffused and nonlithium-diffusedn-type float-zone silicon are found to be comparable. The isochronal annealing of 90 per cent of the neutron damage in lithium-diffused material takes place between 300° and 380° K. The dominant contribution to this annealing is attributed to the diffusion of lithium in silicon.

ISSN:0033-7579    

DOI:10.1080/00337576908243984

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The energy spectrum of a ‘Fexitron’ flash X-ray generator marketed by Field Emission U.K. Ltd. and operated at 500 kV has been determined by measuring the attenuation of the single pulses through plane metal attenuators with LiF thermoluminescent dosimeters. The results have been analysed by two different iterative numerical procedures using tabulated attenuation coefficients to determine the distribution of photon fluence in the pulse. Other methods of analysis are discussed and estimates are made of the errors involved in the various methods.

ISSN:0033-7579    

DOI:10.1080/00337576908243985

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

During thermal-neutron irradiation, Frenkel defects are produced in CdTe following radiative capture of thermal neutrons by113Cd. The resulting excited114Cd nucleus recoils out of its lattice position due to the emission of about 9 MeV of prompt gamma rays. The properties of these defects were studied by measuring the Hall effect and electrical conductivity before and after successive irradiations. The results indicate that a cadmium interstitial-associated defect may be responsible for hole removal inp-type CdTe. This defect recovers in an annealing stage centered at 130°C.

ISSN:0033-7579    

DOI:10.1080/00337576908243986

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A computer simulation of short term annealing of 5- and 20-keV displacement cascades in α-iron has been carried out. A Monte Carlo technique was used to move the defects in correlated random walks on a bcc lattice. Correlations extended to 10th neighbors for interstitials and 5th neighbors for vacancies. A low temperature simulation permitted only interstitial migration, whereas a high temperature simulation permitted both interstitial and vacancy migration with a jump frequency ratio of 100 to 1. Temperature sensitive parameters included the jump frequency of the di-interstitial relative to the single interstitial and the recombination region for unlike defects.

ISSN:0033-7579    

DOI:10.1080/00337576908243987

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Dielectric plastics are being developed as high exposure dosimeters. The principle of operation is based on the relationship between the absorbed dose and the increased chemical reactivity of these dielectric solids. Polycarbonate plastics can be utilized in measuring absorbed dose in the range of about 107-109rads. The advantages of the technique lie in the low cost of the detectors, ease of data readout, and high degree of reproducibility achievable. It is hoped that the method can be extended to include the dosimetry of massive doses of soft, low penetrating power X- or γ-radiations.

ISSN:0033-7579    

DOI:10.1080/00337576908243988

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

In recent years, in a number of laboratories throughout the world, a considerable amount of effort has gone into the development and the understanding of organic nuclear charged particle track detectors. Even in their developmental stage these detectors have found numerous applications in several scientific fields. The object of this paper is to present a brief résumé of some of the most important recent developments in this field. The scope is limited to the pre-etching phenomena; etching and post-etching treatments are covered by Medveczky.(1)

ISSN:0033-7579    

DOI:10.1080/00337576908243989

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

It is well established that ion bombardment of certain solids leads to the formation of a disordered, often amorphous, phase. Though it is not difficult to describe the fractional disordering (Fd) as a function of the depth and of the volume disordered per ion impact, there is still no adequate model which relatesFd, to the fraction of inert gas (FIB) that would be released during the thermal annealing or chemical dissolution of the disorder. It is shown that an analytically manageable relation betweenFdandFIBcan be obtained on the basis of four assumptions, the most critical of which is that each ion impact gives rise to a compact, rather than fragmented, disordered region. This relation is shown to be reasonably well obeyed with Al2O3, diamond, and ZrSiO4, making it possible to estimate both the effective depth of disordering (Rd) and the size of the disordered regions (Vd1/3).Rdfor 10-keV Kr bombardment is with all three substances roughly 140 A. Likewise,Vd1/3is 14–20 A with Al2O3, 13–16 A with diamond, 20–27 A with ZrSiO4, and thus similar to what is observed using alternative approaches (e.g. electron microscopy) with Al2O3, Ge, Si, and ZrSiO4.

ISSN:0033-7579    

DOI:10.1080/00337576908243990

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A cryostat for electron irradiations at liquid hydrogen or helium temperatures is described. The cryostat uses two concentric liquid coolant containers, of which the inner reservoir is sealed and acts as a heat exchanger through ebullition and recondensation of the coolant gas. This allows irradiations with a power input from the beam of up to a few watts, and when the sample is thermally isolated allows it to be annealed up to room temperature.

ISSN:0033-7579    

DOI:10.1080/00337576908243991

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Chemical reactivity along the trajectory of a charged particle in a dielectric solid depends on the density of radiation-damaged species. In inorganic crystals such as are found in meteorites, cosmic rays can be identified by etching for a long time and measuring the entire etchable ranges of the slowing particles, which are related to their atomic numbers. In plastics, the etching rate is an increasing function of radiation damage density. Measurements of etched ‘cone’ lengths at different points along the trajectory of a particle that passes thruough several sheets provide a very sensitive measure of atomic number. In favorable cases it is possible even to resolve isotopes with the same atomic number.

ISSN:0033-7579    

DOI:10.1080/00337576908243992

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Thompson and Buckc(l)have recently reported the results of experiments in pure copper which appear to have unusual significance with regard to providing a resolution of the long-standing problem of assignment of recovery stages in metals. Their major observations are summarized in Figure 1. The most notable characteristics which may be observed from this figure or otherwise reported by Thompson and are:

ISSN:0033-7579    

DOI:10.1080/00337576908243993

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor