摘要:

Commercial polyimide (PI, ‘kapton') and polycarbonate (PC, ‘makrofol') foils have been irradiated with 135 MeV Ar5+and 340 MeV Xe7+ions, respectively, and subsequently boiled in a 5 mole/ltr LiCI solution for different times. The depth distributions of Li diffused into the foils suggest that the doping proceeds via regular diffusion, into both unirradiated bulk and into tracks. Low fluence irradiations appear to lead to a compaction or densification of the polymer matrix. One consequence of this is a decreasing Li uptake with increasing fluence. For higher ion fluences the Li uptakeproportional to track densitybecomes dominant. It is possible to define, to first order, a mean ‘effective track radius’ for the average amount of lithium taken up per track, and this can be shown to be of the order of only an Å. The diffusional behaviour of lithium suggests that tracks in 340 MeV Xe ion irradiated polyimide act as open micropores for diffusing dopants. Conversely, in 135 MeV Ar irradiated PC, the dopant may only access the primary track core by passage through nearby undisturbed polymer target. A characteristic surface effect is the eventual appearance of crater-like profiles associated with the cores of ion tracks at projectile points of entry. These may be partly due to reverse ‘blow-out’ (backwards sputtering) in plumes of dissociated polymeric matter.

ISSN:1042-0150    

DOI:10.1080/10420159408219250

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A phenomenological model describing the dependence of deformation processes on ion implantation conditions is proposed. Experimental results of defect formation as well as amorphisation in silicone for the implantation with Ne+, Ar+and Kr+ions in the temperature interval of 150–500 K and for ion current densities of 0.5 to 4.0 μA/cm2are presented. An analysis of the experimental data within the framework of the proposed model has been carried out. The basic characteristics of the defects appearing at silicon amorphisation also have been defined.

ISSN:1042-0150    

DOI:10.1080/10420159408219251

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Some years ago the Transmission Electron Microscopy of High Resolution Replica (TEMHRR) has been successfully used to show the damage created in Si single crystals by channeled In ions [1]. In the present paper the capacity of the same technique to reproduce the full in-depth damage distribution in 1014Zn+/cm2implanted GaAs is shown.

ISSN:1042-0150    

DOI:10.1080/10420159408219252

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Conductivities of polymers, irradiated up to high doses, have been studied since two decades. We have expanded this knowledge to the low dose regime, where single non-overlapping in tracks are found. These tracks exhibit somethough very lowconductivity. When the conducting zones of these ion tracks overlap, the overall polymeric conductivity comes to saturation. Variations in conductivity parallel and transverse to the ion tracks are studied, and new hints for the underlying conductivity mechanism are summarized.

ISSN:1042-0150    

DOI:10.1080/10420159408219253

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Thermal-spike evolution has been investigated using a method of numerical hydrodynamics. A pattern of origination of a shock-wave arising from a spike is presented. The fraction of energy taken away by the wave has been calculated as a function of the temperature of the spike. The fraction increases with the temperature but in the possible range of that the fraction is no more than about a half of the energy of the spike.

ISSN:1042-0150    

DOI:10.1080/10420159408219254

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

By the methods of structural investigation a new state has been found in ion irradiated BCC the Fe-Cr alloys (model and commercial) within the narrow range of radiation parameters (doses, radiation temperatures and flux densities).

ISSN:1042-0150    

DOI:10.1080/10420159408219255

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper we discuss the results of thermoluminescence (TL) studies carried out on freshly quenched crystals of KBr doped with ∼50ppm of Eu2+ions which were X-irradiated at room temperature. The TL glow curve of this phosphor material consists of three glow peaks at 355, 376 and 398K whose intensities increased as a function of X-irradiation time. The TL glow peaks were analyzed by the total curve-fitting method in order to obtain the characteristic parameters; activation energy, pre-exponential factor and kinetic order. The spectral character of the emission recorded during thermoluminescence was found to be the same for all glow peaks and consists of a broad band centered at -420 nm. This band is composed of two overlapping bands peaking at 419 and 460 nm. The former band is due to the well known fluorescence of Eu2+ions corresponding to the transition 4f65d (T2g) →8S7/2, while the latter may be associated with the recombination of F-centers with the radiation induced interstitial chlorine atoms which are thermally released from traps. It is proposed that the model of the TL process most consistent with our experimental results is one in which the Eu2+impurity acts as an electron trap during the irradiation process and that the radiation induced center (partner of an F center) and the Vkcenter (partner of an Eu+ion) are trapped together in the form of a Cl−3molecular ion at the Eu2+-cation vacancy dipoles and their smaller aggregate complexes such as dimers, trimers, etc. During the TL run, the H and Vkcenters escape from the trap and recombine with the complementary center giving rise to the observed TL emission spectra. The dosimetric characteristics of the KBr:Eu2+phosphor material are also reported.

ISSN:1042-0150    

DOI:10.1080/10420159408219256

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A recent study of difference in surface etching rates of the+xand-xplanes ofx-cut synthetic quartz has led to a more detailed understandings of the results in our previous paper, ‘Fission Fragment Registration in Synthetic Quartz'.1Considering that the difference must be due to the anisotropy of the etching rate, a general treatment of the process in which tracks are developed with an anisotropic bulk etching rate is obtained. The results are applied to fission fragment tracks inx-cut synthetic quartz plates.

ISSN:1042-0150    

DOI:10.1080/10420159408219257

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

EPR measurements on single crystals of Cu2+molecular ion doped in Thallium Cobalt Sulphate Hexahydrate, Tl2Co(SO4)2. 6H2O have been performed over the temperature range 120–390 K, at X-band (≈9.205 GHz). The orientation dependence EPR spectra reveal that the impurity ions enter at the divalent cobalt site in the lattice, exhibiting two symmetry related equivalent complexes. The principal parameters have been estimated and found to be axially symmetric and dependent on temperature. The Fermi contact term (K) and covalency parameter (α) are evaluated from the principal parameters.

ISSN:1042-0150    

DOI:10.1080/10420159408219258

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The absorption coefficient (α) was obtained for different γ-doses. The analysis of the data revealed the existence of optical allowed direct transition from Egd= 5.82 to 6.03 eV for an increase of the radiation doses from 1 M rad to 10 M rad. An absorption band appears at ∼310 nm., shifted towards the short wavelength as the doses increase. This band could be related to electrons or holes trapped at lattice defects and associated with a growth of colour centres.

ISSN:1042-0150    

DOI:10.1080/10420159408219259

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor