摘要:

Experimental sputtering yields of thin films for 1.725 MeV1H+bombardment have been measured on various targets of thicknesses from 2 to 320 nm: carbon, titanium, chromium, nickel, tantalum, tantalum oxide and gold. The results are compared to old models from Goldman and Kaminsky and to Sigmund's theory. Relatively good agreement between experimental data and theory is found. The influence of some parameters including the nature of the target, the target thickness, the nature of the substrate and the nature of the projectile is discussed.

ISSN:1042-0150    

DOI:10.1080/10420159408219983

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Infrared (IR) transmission spectra of ion implanted polymers are evaluated as a function of the implantation fluence. From the IR line assignment, clues for the radiochemical processes are derived. For low dose irradiated samples the transmission grows linearly with fluence, but comes to saturation with increasing dose. For PMMA the relations of transmission vz. fluence for different ions scale with the nuclear energy transfer.

ISSN:1042-0150    

DOI:10.1080/10420159408219984

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effect of irradiation with low energy argon ions (40 KeV, and fluences of 1015to 1017ions/cm2) on deposited thin films of Fe-30% Ni alloy was investigated using RBS and TEM techniques. The thickness of these films is about 65 ∓ 10 nm deposited on ceramic, KBr, and Be foils substrates. Gas bubble formation and profile distribution of the implanted argon ions were investigated. Formation of an ordered phase of Fe3Ni during irradiation appears to inhibit gas bubble formation.

ISSN:1042-0150    

DOI:10.1080/10420159408219985

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We investigate the change of the Si(111) surface under energetic alkali ion bombardment by a combination of both ion-induced electron spectroscopy and time of flight ion scattering spectroscopy (TOF ISS) techniques. The analysis carried out in the dynamical regim showed that a steady state is obtained, characterized by an alkali saturation at the Si surface. The saturation value depends on the sample temperature, the incidence angle, the nature and the energy of the alkali ion. In the case of K-Si system formed by bombarding Si sample with 4 keV K+ions up to the saturation state, TOF ISS experiments allowed us to confirm K ‘trapping’ in the first atomic layers. Moreover the K depth profile and the K atom concentration at the surface were determined. The experimental results were compared to a diffusion-like model taking into account the modification of the concentration profile of implanted atoms under the combined effects of implantation, sputtering, generalized diffusion, chemisorption and desorption. Agreement between theoretical data and experimental results was found for K-Si combination concerning the irradiation time needs to reach the steady state and the potassium atom density in the first atomic layers.

ISSN:1042-0150    

DOI:10.1080/10420159408219986

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

An experimental study of the drain-substrate junction controlled by gate voltage has been carried out on n-MOSFETs. The experimental procedure to acquire the current-voltage characteristics is described together with a theoretical analysis that leads to extract electrical and structural parameters for a description of carrier transport phenomena. The determination of junction parameters is shown to be a powerful method for the evaluation of radiation degradations of the performances of the devices.

ISSN:1042-0150    

DOI:10.1080/10420159408219987

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Gamma ray induced decomposition of zirconium and thorium nitrates in sulfate matrices doped with common cation and alkali metal (Na, K) cations at various concentrations has been studied. G(NO−2) values of the nitrate salt are found to increase with the concentration of the sulfate in the binary mixture. Electron spin resonance (ESR), thermoluminescence (TL) and reflectance spectral studies suggest the formation of radical species SO−4, SO−3, O−3, O−2; which may be responsible for the energy transfer to nitrate. Efficiency of energy transfer follows the order K2SO4> Na2SO4> Zr/Th sulfate. A possible mechanism has been suggested.

ISSN:1042-0150    

DOI:10.1080/10420159408219988

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The mechanism and nature of radiation defects creating with electron and neutron irradiation in LTB crystals are discussed.

ISSN:1042-0150    

DOI:10.1080/10420159408219989

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Measurements of the electrical properties of unirradiated as well as γ-irradiated La2CuO4crystals were carried out at different temperatures in the frequency range of 0.1-100 kHz. Thermoluminescence (TL) studies were also performed on such crystals in the temperature range of 300-600K. The conductivity of the unirradiated La2CuO4crystals were found to obey the power law frequency dependence at each measured temperature below the transition temperature (Tc= 450K). The activation energies for conduction and dielectric relaxation time have been calculated. The TL response and the dc resistance were found to increase with γ-irradiation dose up to 9-10 kGy. The results showed that the ferroelastic domain walls of La2CuO4crystal as well as its TL traps are sensitive to γ-raditaion. This material can be used in radiation measurements in the range 225 Gy-10 kGy.

ISSN:1042-0150    

DOI:10.1080/10420159408219990

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A secondary ion mass spectrometry (SIMS) and a neutral molecule mass spectrometry (NMMS) study of deuterium trapping in a single crystalline silicon as a result of ion irradiation at fluences 1016--1018cm-2are presented. An attempt has been made to observe the formation and evolution of defect profiles containing one or two deuterium atoms (SiD- and SiD2-complexes). The proposed model of radiation-induced sequential reactions describes satisfactorily the accumulation of SiD- and SiD2-complexes and the reemission of D2-molecules.

ISSN:1042-0150    

DOI:10.1080/10420159408219991

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The mechanism of reversible radiation-induced structural transformations in vitreous As2S3is studied using IR Fourier-spectroscopy technique. It is established that observed effects are associated with destruction-polymerization processes (transformations of the products containing homopolar S-S and heteropolar As-S bonds into the products on the heteropolar As-S and homopolar As-As bonds basis respectively) in vitreous matrix which lead to the stabilization of (As4+, S1) coordination defects.

ISSN:1042-0150    

DOI:10.1080/10420159408219992

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor