摘要:

The annealing behavior of election irradiated copper was studied by means of positron lifetime. In Stage III recovery, the long-lived component appeared in the lifetime spectrum. It was attributed to the formation of three-dimensional micro voids. Therefore it is concluded that vacancies are migrating in this temperature range. The lifetime component corresponding to micro voids remains up to a rather high temperature annealing. In addition to micro voids, the existence of other kinds of defects was concluded from the detailed analysis of the lifetime data. The defects formed in Stage III disappeared at high temperature but below the temperature of annealing out of micro voids. These defects were attributed to vacancy loops. Vacancy loops were also formed through the vacancy clustering in Stage III.

ISSN:0033-7579    

DOI:10.1080/00337577708237459

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

It is shown that in rare gas sensitized radiolysis of ethanethiol, the hydrocarbon products are formed through charge exchange with the rare gas ions.

ISSN:0033-7579    

DOI:10.1080/00337577708237460

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Optical measurements have been made of the concentration ofFcentres produced in LiF by 2 MeV proton, 28 MeV lithium, 28 MeV deuteron and 56 MeV alpha particles. An assumption is proposed to explain the growth ofFcentres with the irradiation. The creation of defects by one particle is supposed to be localized in a volume surrounding the particle trajectory, named the tube, associated with the particle. In a first approximation, the tube is compared to a cylinder and taking into account the high energy loss of the energetic ions, the lateral distribution of defects in a tube is supposed to be homogeneous. The experimental result ofFcentre creation are fitted by the hypothesis. The mean radii for the tube are respectively: 12, 63, 70 and 165 A for the particles2H (2 MeV),7Li (28 MeV) and4He (56 MeV). The temperature of the irradiation has an influence on the mean radius.

ISSN:0033-7579    

DOI:10.1080/00337577708237461

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

An energetic ion which is incident on a solid target causes a momentary temperature increase in the impact region, i.e., a so-called thermal spike occurs. Such spikes are capable of causing (or supplementing) disordering, precipitation, crystallization, electronic excitation, stoichiometry change, desorption, and sputtering, it being the contribution to sputtering that we consider here. The approach used is compatible with modern damage-distribution theory. Thus the temperature profile left by the incident ion is taken as a three-dimensional Gaussian with parameters appropriate to power-law scattering, and is used as the initial condition for solving the heat-conduction equation. Let us write this solution asT = T(t, y), wheretis time andyis a dimension parallel to the target surface. The vaporization flux from a solid surface is taken aspn½(2π<m,>kT)−½wherep, the equilibrium pressure of a vapor species containingnatoms, can be writtenas poexp(−L/T), poandLare constants largely independent of temperature, and <m2> is the mean mass per atom of target. The thermal sputtering coefficient then follows as

ISSN:0033-7579    

DOI:10.1080/00337577708237462

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The presence of vacancy defects in α-Zr, irradiated at 320 >T> 290 K with 1.5 MeV electrons, has been indicated by positron annihilation measurements. It was found that positron lifetimes associated with annihilation in well-annealed α-Zr, fell in the range 173 to 181 psec, with no obvious dependence on the sample purity or grain size (down to 10 microns). After irradiation, however, the mean lifetime increase-associated with defect trapping-was found to be bigger for lower purity Zr, a result that was emphasized in a multicomponent analysis. Isochronal annealing studies on the less pure Zr showed nearly continuous recovery up to 550 K, while other specimens exhibited no measurable recovery below 450 K. Potential effects of particular impurities are considered in terms of their interstitial/substitutional nature, inferred from tracer diffusion studies.

ISSN:0033-7579    

DOI:10.1080/00337577708237463

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In this paper some problems present in the extraction of nuclear lifetimes from blocking experiments are discussed with reference to experimental results relative to the “zero reaction time” (p, a) resonance at 1183 KeV in17Al single crystals. The crystal preparation and the particle detection are described in detail. A simple method of reducing the collected data to a one-dimensional radial distribution is also presented. The accuracy of a computer simulation of the blocking effect of 2-MeV α-particles in the crystal is discussed. It is shown that by such a method an angular distribution of emerging particles from the crystal is obtained that agrees with the experimental one if reasonable “multiple scattering” effects are taken into account by properly folding in a gaussian angular broadening.

ISSN:0033-7579    

DOI:10.1080/00337577708237464

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The electrical and optical properties of semiconductive compounds of InAs and InP were studied in wide concentration (2 × 1016−2 × 1018) cm−3and temperature (4.2–300) K ranges prior to and after electron irradiation with 50 MeV energy.

ISSN:0033-7579    

DOI:10.1080/00337577708237465

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A simple transfer cryostal for annealing spectra measurements is described. The temperature region is from 78 K to 400 K. The main advantages of the above cryostat are:

ISSN:0033-7579    

DOI:10.1080/00337577708237466

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337577708237467

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337577708237468

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor