Classified
abstracts
1875-1890
designs for the 7 BeV proton synchrontron and for the 6 BeV electron synchrotron. I F Malyshev et al, Elec Znstr High-Energy Phys (Collection of Papers), NO 1, 1966, 160-169. Rep AEC-TR-6636 (Israel Programme for Scientific Translations Ltd, Jerusalem). . 32 1875. Study of tbe permeability of certain materials to tritium. (France) Certain materials intended for use as a protection against gaseous tritium are discussed. The difficulties which arise from the fact that the amounts in active tests must be lOlo times less than those which would have been used in the case of hydrogen are discussed. B Caire and Y Sutra-Fourcade, Rep CEA-R-3018, 1966 (CEA, Centre de Production de Plutonium, Marcoule, France) (in French). 32 1876. Accelerator progress, experimental programme and instrumentation. (USA) The performance of the proton linear accelerator is discussed, and brief accounts are given of the experiments performed using the machine. Improvements to both the machine and the experimental instrumentation are outlined. Performance tests on a new 500 keV injector are reported. R P Featherstone et al, Rep TZD-23395, 1966 (Minnesota Univ, Minneapolis, J H Williams Lab, Nuclear Physics). 32 1877. Further improvements on the 10 kV ion accelerator. (USA) The relationship between arc conditions and filament lifetime is discussed with reference to the changing of the arc filament power supply to a dc supply with a ripple of less than 0.15 V. A modification to correct the problem of arc-disrupting discharges is described and the effects of extraction voltage and admixtures of other gases with CO* on ion production efficiency are considered. H M Pohiit and W R Erwin, Chem Biodynamics, Rep UCRL-16806, 1966, 58 (California Univ, Berkeley, Lawrence Radiation Lab). 32 1878. Support for the high voltage accelerator programme. (USA) Technical details on design, development and installations in support of the high voltage accelerator programme are reported. Progress is recorded in the following areas: vacuum techniques in the high voltage accelerator, scattering chamber for gaseous targets, duoplasmatron arc-current regulator, and pulsing equipment for the Tandem Van de Graaff accelerator. Anon, Rep ORNL-3875, 1966, 159-163 (Oak Ridge National Lab, Znstr Control Div). 32 1879. Diagnostics
of accelerating
plasma.
(USA)
The radial electron density distribution, the electron temperatures, and the shapes of the current sheets produced in coaxial plasma accelerators of different radius ratio were determined, using fast photography and spectroscopic techniques. Pronounced polarity effects in these accelerators were observed for most of the working gases, except hydrogen. The validity of local thermal equilibrium in the plasma was studied and the theoretical results are given. T N Lie et al, Rep NASA-CR-82950, Feb 1967 (Catholic Univ of America, Washington, Dept Space Science and Applied Physics). 32 : 40 1880. An improved suiphur hexafluoride gas handling system for a potential drop particle accelerator. (USA) An improved SF. gas handling svstem has been designed and built for a 3’MeV accelerator. The purpose of the system is-to remove the gas from the accelerator when opening is necessary, purify and store it, and return it to the vessel. Design considerations, fabrication techniques and performance evaluation are given. S J Marsik et al, Rep NASA-TM-X-52274, 1967 (NASA, Lewis Res Centre, Cleveland, Ohio). 32 1881. Tandem isotope separator-mass
spectrometer
ionic collision processes. USA) An isotope separator and mass spectrometer
for the study of
system working over an energy range of 0.25 to 60080 eV is described. The source, the focusing system, the deceleration lens and the collision chamber are presented with their special features. The differential pumping system used and the system for measuring the pressures are discussed. T F Moran and L Friedman, Rev Sci Znstrum, 38 (5), 1967, 668-676.
1882. Characteristics source. (USA)
of a low energy
duopiasmatron
negative
32 ion
A duopiasmatron for negative ion beams of less than 5 keV energy is described. Design parameters are given for the ion source, the construction of its electrodes, the apertures and the vacuum seals. The operation of the ion source and the results obtained with the duopiasmatron are also given. W Aberth and J R Peterson, Rev Sci Znstrum, 38 (6), 1967, 745-748. 1883. Design parameters (USA)
32 of iodine vapour ultraviolet photon counters.
An experimental set-up of the iodine vapour counter is described. This device provides design data, by setting the probe-window distance to various desired values, then evacuating the counter to less than 0.03 torr, and finally filling it to the specific gas pressure desired. The modifications of the characteristic curves are given. W E Kauppiia et al, Rev Sci Znstrum, 38 (6), 1967, 811-812. 33. GENERAL
PHYSICS
A high voltage triei~ode
AND ELECTRONICS 33 : 32 electron gun. See abstract number 1872.
33 : 37 1884. Two-crystal, vacuum monochromator. ‘(USA) Design and construction of a vacuum two-crystal instrument for high resolution spectroscopy at long wavelengths is reported. The drive assembly and the construction of the vacuum envelope are emphasized. The instrument provides for coordinated rotation of both crystals, source and detector. R D Desiattes, Rev Sci Znstrum, 38 (5), 1967, 616-620. 33 1885. Highly efficient, inexpensive, medium current ion source. (USA) An ion source which provides deuterium ion currents up to 10 mA at input powers of about 100 W, is described. The ion source utilizes a diffuse, filament excited dc discharge produced in the 1O-3 torr pressure region and incorporates an ion extractor as a part of the plasma chamber. The extractor and discharge chamber exit aperture form a converging lens that shapes the ions into a small diameter beam, which exits the chamber through a small orifice in the extractor. The construction of the device is described and its performance is discussed. R L Hirsch and G A Meeks, Rev Sci Znstrum, 38 (5), 1967, 621-624. 33 1886. X-ray topographic camera. (USA) The versatile, small, X-ray topographic camera described is primarily applicable to projection topography by the Lang technique. The design incorporates an oscillation motion as well as several unique alignment motions. Results of topographs of silicon and ruby are shown. G J Carron, Rev Sci Znstrum, 38 (5), 1967, 628-631. 33 1887. High temperature camera for X-ray topography. (USA) An X-ray camera suited for transmission topography and capable of continuous operation at 900°C is described. The camera chamber can either be evacuated (I x 1O-3 torr) or used with an inert atmosphere. I A Biech et al, Rev Sci Znstrum, 38 (5) 1967, 638-641. 33 1888. NZ6 target for electron scattering. (USA) A NZ5 target system for high energy electron scattering is described. The target material is ammonia NIGHS liquefied by dry ice. The target design, the production of heavy ammonia and the operational procedures are described. The seals used are based on indium wire. E B Daily and M Croissiaux, Rev Sci Znstrum, 38 (5), 1967, 646-648 33 1889. Ultrathin Al,O, support Iiims for electron microscopy. (USA) A technique for preparing oxide films of thicknesses in the range 75-100, A is based on anodizing aluminium foil, and etching only selected parts by means of photo-lithography, leaving the remainder as a supporting grid. J Varon et al, Rev Sci Znstrum, 38 (5), 1967, 691-692. 33 1890. Cyclotron (USA)
harmonic
resonances
in an electrodeless
discharge.
Electron-cyclotron resonances in rf excited, electrodeless helium discharges were investigated experimentally. The discharge simulates 625