摘要:

A radiotracer technique for measuring the reflected fraction of heavy ions impinging at keV energies on solid surfaces is described. This technique consists essentially in measuring the distribution of radioactivity between the target and a cylindrical collector surrounding it. A series of experiments has been performed to establish the reliability and the limits of the technique.

ISSN:0033-7579    

DOI:10.1080/00337577108230450

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Measurements of the reflected fractions of sodium, potassium, and krypton ions impinging on polycrystalline silver and gold and amorphous germanium targets have been made at medium keV energies. The reflected fraction depends strongly on mass ratio and weakly on energy. Previous calculations of ion reflection (based on random slowing-down by elastic collisions in an infinite medium) have been extended. Corrections to the calculated values due to electronic stopping and surface effects have been estimated. Agreement between measurements and calculations is satisfactory.

ISSN:0033-7579    

DOI:10.1080/00337577108230451

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Pulse radiolysis methods with simultaneous optical and electrical registration have been used in a study of transient charged species in pure hexamethylphosphortriamide (HMPA) and its solutions of alkaline metal salts. A number of transient optical absorption bands were observed, including the solvated electron (es) spectrum. The experimental technique allowed one to establish some primary reactions in the radiolysis mechanism of HMPA and to determine mobility values of charged species. In case of salt solutions an increase ofG(es) up to the value of total ionization as a result of salt concentration increase (10−3−3:10−1M) was observed. The possibility of thermalized electron stabilization by cations of alkaline metals is discussed. The concentration dependence ofG(es) is described by an analytical formula if one assumes thatesis stabilized by metal cations in the form of a complex [M+…e−2]. The transient absorption band observed in the near IR is ascribed to this complex. The time of initial recombination is estimated.

ISSN:0033-7579    

DOI:10.1080/00337577108230452

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The yields of all unsaturated products of gamma radiolysis of ethylene in the gas-phase decrease markedly with the increase in total dose absorbed. Dose effects are particularly severe at conversions above ca. 5 × 10−2per cent.

ISSN:0033-7579    

DOI:10.1080/00337577108230453

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Changes in the mass spectra of amino acids and dipeptides have been observed after γ-radiolysis. The primary reaction in the dipeptides is bond cleavage. Pyrolysis reactions due to local heating appear to play no part in the radiolysis of these substances in the solid state.

ISSN:0033-7579    

DOI:10.1080/00337577108230454

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

In this paper, we discuss the experimental problems and radiation noise sources associated with flash X-ray machine (FXR) and linear accelerator (LINAC) electron-beam TREE experiments. Special testing techniques and test fixture design guidelines are presented. Wiring diagrams for a properly designed general-purpose electron-beam test fixture and control unit are shown, in addition to photographs which illustrate the geometry-dependent shielding and noise reduction techniques. Techniques for improving both electron radiation shielding and RF shielding efficiencies are represented.

ISSN:0033-7579    

DOI:10.1080/00337577108230455

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Two types of commercially available carbon fibers (high tensile strength, HTS, and high modulus, HMS) were irradiated in the Ground Test Reactor in environments of air and of liquid nitrogen (LN2). The tensile strength of HTS fibers irradiated in air increased sharply above a fast-neutron fluence of 6 × 1017n/cm2(E> 1 MeV) and was 17 per cent greater than the strength of unirradiated control fibers at a fluence of 8.5 × 1017n/cm2, but then the strengrh began to decrease for additional neutron exposure in air and fell 25 per cent below the control strength at the highest fluence of 4.5 × 1018n/cm2. However, when irradiated in LN2where surface oxidation did not take place, the room-temperature strength of HTS fibers continued to increase beyond 8.5 × 1017n/cm2and became almost 30 per cent greater than the control strength for a fluence of 3 × 1018n/cm2. The tensile strength of HMS fibers irradiated in air increased slowly but steadily with neutron exposure and was only 4 per cent greater than the control strength at the highest fluence of 4.5 × 1018n/cm2; the room-temperature strength of the HMS fibers decreased by 13 per cent when irradiated to a fluence of 3 × 1018n/cm2in LN2.

ISSN:0033-7579    

DOI:10.1080/00337577108230456

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

A sectioning technique for sodium chloride single crystals has been developed. This technique, which is based on the formation of a silver chloride film, is capable of removing layers of constant thickness up to 2μg/cm2. Being insensitive to radiation damage of the. NaCl-surface this film technique can be applied in studies of penetration and diffusion in NaCl. An electro-magnetic isotope separator has been used to implant radioactive phosphorous, krypton and xenon atoms in single crystals of sodium chloride, and examples are shown where the film technique has been applied for the study of range distributions and diffusion processes.

ISSN:0033-7579    

DOI:10.1080/00337577108230457

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Results of isochronal anneals following electron irradiaton of copper single crystals indicate theIBrecovery is enhanced for a (100) sample compared to theIBrecovery for a (110) sample and a polycrystal sample. Comparison of these results with data from aluminum single crystals indicates a tentative assignment of theIBdefect in copper to damage produced in the (100) direction.

ISSN:0033-7579    

DOI:10.1080/00337577108230458

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor