摘要:

Well annealed molybdenum was irradiated with 63 MeV nitrogen and 72 MeV oxygen. Isochronal annealings in high vacuum of the radiation damage were followed with positron lifetime measurements and compared to previous positron investigations of radiation damage in Mo. The presence of the injected ions decrease the void growth rate apparently because they act as nucleation centers. The size distribution of vacancy clusters in the displacement cascades is characterized and its dependence on recoil energy is discussed.

ISSN:0033-7579    

DOI:10.1080/00337578308224718

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

From a compilation of known literature, the substitutional fraction of boron in silicon is depicted in a diagram as a function of implantation dose and annealing temperature. Samples implanted at 1 1016 B/cm2 and annealed at 900, 1000 and 1100°C for 1 hour each are examined by the(n, α)method and compared to the RBS signal of the host atoms in various directions. Our results indicate a gradual transition from completely random positions after 900°C anneal to substitutional sites after 1100°C anneal.

ISSN:0033-7579    

DOI:10.1080/00337578308224719

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A systematic TEM investigation has been made of helium bubble growth in type 316 stainless steel. Commercial stainless steel samples have been vacuum annealed following room temperature helium implantation to a concentration of 5 × 1026 He m−3. The bubble growth kinetics have been determined by measuring the mean bubble radius at annealing times in the range 1 to 200 h for temperatures of 873, 923 and 1023 K. At the lower two temperatures the bubble growth mechanism is believed to be migration and coalescence, with the migration limited by volume diffusion of the metal atoms. Four additional anneals for 2 h at temperatures in the range 923-973 K have been made to determine the activation energy for diffusion. This is found to be 4.9 eV (assuming the migration is limited by volume diffusion). At 1023 K and for annealing times of less than 8 h, bubble growth appears to occur mainly by the acquisition of thermal vacancies from the sample surface. At longer annealing times the bubble migration becomes limited by the nucleation of atomic ledges on the bubble facet and the rate of bubble growth is reduced. The ledge energy is estimated to be 1 × 10-11 J-m−1.

ISSN:0033-7579    

DOI:10.1080/00337578308224720

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The migration enthalpy of monovacancies in α-Fe,H1vm, is deduced from the growth of voids during electron irradiation as studied by Kitajima and co-workers in a high-voltage electron microscope. In this wayH1vM = (1.3+0.1−0.3) eV is obtained, in excellent agreement withH1VM = (1.28±0.25) eV as deduced by Schaeferet al.from high-temperature equilibrium experiments. The disagreement betweenH1VM andH111= (0.55±0.05) eV, the activation enthalpy in recovery stage III of %aL-Fe after irradiation or cold-work, excludes the one-interstitial model but is in accordance with the two-interstitial model of point defects in metals.

ISSN:0033-7579    

DOI:10.1080/00337578308224721

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Spatial distribution and lattice location of implanted As atoms in <111> and <100> Si as well as spatial distribution of radiation defects were studied by the RBS techniques after channeled implantation of 30 keV As+ ions with a dose of 3 × 1015 cnr2 at 300°C. The profile of As atoms was observed to have two maxima due to superposition of the profiles of initially nonchanneled and dechanneled ions. The aligned As+ ion beam generates fewer defects than the random one. The radiation defect profiles both after channeled and random implantations at 300°C are of the well pronounced bimodal type with a minimum at the depth of the maximum of elastic energy losses of nonchanneled As+ ions. A model of the layer of disordered zones with vacancy-defect nuclei and interstitial-defect shells is proposed. Annealing by a ruby laser with a pulse energy density of 1 J/ cm2 and duration 40 ns results in removal of the radiation defects and flattening of the substitutional As atom profile.

ISSN:0033-7579    

DOI:10.1080/00337578308224722

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The regularities of reflection of molecular nitrogen ions with a 30 keV initial energy from the (100) Cu crystal face have been studied experimentally. The ion fraction reflected without dissociation has been found to be a nonmonotonic function of crystallographic direction. The results obtained are discussed in terms of a two-atom model.

ISSN:0033-7579    

DOI:10.1080/00337578308224723

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A method is presented for the determination of the flux profile of ions channeled in the main directions of a crystal lattice. The Lindhard continuum model is used, but in the analytical calculations a parameter is introduced which encompasses the influence of the energy loss of the channeled ions in the crystal as well as the influence of lattice defects and surface layers. This parameter may be interpreted as the root-mean-square angular spread of the ion beam. Its value is determined by fitting the calculated yield of a close encounter reaction with solute atoms at definite interstitial sites to the yield found experimentally. The method was tested on boron atoms implanted in tungsten single crystals.

ISSN:0033-7579    

DOI:10.1080/00337578308224724

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Yields for positive and negative secondary ions desorbed by 12C, 160 and 32S ions with velocities ν≳109cm s 1 and equilibrium charge state distributions have been measured. The data show that the yields depend on the charge and the velocity of the primary ions and the secondary ion species. They are independent of the primary ion mass.

ISSN:0033-7579    

DOI:10.1080/00337578308224725

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Studies of the interaction of 2 MeV He+ ions, employed for Rutherford backscattering/channeiling of disorder in InP, with the disorder generated by pre-implantation of 40 keV N+ ions at room temperature are reported. It is shown that for initially undamaged substrates, He+ irradiation generates disorder whilst for N+ implantation damaged substrates He+ irradiation anneals disorder. Possible mechanisms to account for this behaviour are discussed and the potential problem associated with accurate disorder measurements using RBS/channelling outlined.

ISSN:0033-7579    

DOI:10.1080/00337578308224726

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The pre-dose effect has been investigated in Si02 for various ionizing particles and specificallyp, d, α., e−and X-rays. The general features are qualitatively similar; the effect intensity is however rather different for particles with different specific ionization and changes monotonically withs/p.At the same time data on the relative thermoluminescence efficiency(Kfactor) have been obtained.

ISSN:0033-7579    

DOI:10.1080/00337578308224727

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor