1495. The production of 15 μm liquid hydrogen droplets

Classified abstracts 1488-1501 formulated for the range of electric field over which an image potential binds the ions to the electrode surface. Recent investigations on the ionization of gas atoms by a metal surface are utilized in conjunction with steady-state arguments to yield an expression for the ion supply at the electrode surface. N Sama, Rep NASA-CR-93003, 1967, 58 pages (Sci Tech Aerospace Reps, 6 (7), 1059, N68-16449). 33 1488. Investigation of kilovolt ion sputtering. (USA) The yield (injected atoms/incident ion) and the angular distribution of ejected particles are presented for various experimental conditions. Highly polished monocrystalline surfaces of Cu, Mo, Ni, AI and AI~O3 were bombarded by either Cs ~ or Hg * ions. It was found that the yield can be significantly reduced by directing the incident beam along low index crystallographic directions, H P Smith, Rep NASA-CR-72344, June 1967, 106 pages (Sci Tech Aerospace Reps, 6 (8), 1223, N68-17483). 33 1489. Interaction between hydrogen and oxygen atoms and surfaces. (USA) Experimental studies of the scattering of atomic and molecular beams from the surface of freshly deposited crystal films are described. It is demonstrated that, contrary to previous assumptions, the details of the scattering process are not obscured by the use of a beam with a large (Maxwellian) distribution of velocities, J N Smith, Rep GA-8273; AD-662622, Oct 1967, 27 pages (Sci Tech Aerospace Reps, 6 (8), 1143, N68-17961). 33 1490. Possibility of a fast cycling hydrogen bubble chamber. (Switzerland). The hypotheses which were formulated and tested in experiments performed with a 15 cm hydrogen bubble chamber are described, Experimental objectives were to determine whether bubble chamber projects could be improved by increasing the repetition rate. (France) J Badler, CERN Intern Colloquium on Bubble Chambers, Rep CERN67-26.V.2, Aug 1967, 371-377 (Sci Tech Aerospace Reps, 6 (8), 1158, N68-18149). 33 1491.14-ft bubble chamber research and development program, mechanical design details of magnet coil. (Switzerland) Design details for a magnet coil which was incorporated into a onehalf scale model of the 14 ft bubble chamber, are reported. (USA) D A Kassner, CERN Intern Colloquium on Bubble Chambers, Rep CERN-67-26-V.2, Aug 1967, 435-456 (Sci Tech Aerospace Reps, 6 (8), 1158, N68-18155). 33 : 23 1492. A flat membrane inflatable gasket for a large liquid hydrogen bobble chamber. (Switzerland) Manufacturing methods and techniques used in the development of flat membrane inflatable gaskets for the 2 m liquid hydrogen bubble chamber are described. The purpose of the gasket is to ensure leak tightness of the surrounding vacuum tank during cool-down and warming-up operations. R G Stlerlin, CERN Intern Colloquium on Bubble Chambers, Rep CERN-67-26.V.2, Aug 1967, 479-484 (Sci Tech Aerospace Reps, 6 (8), 1159, N68-18159). 33 1493. Engineering aspects of the ANL 12-ft hydrogen bubble chamber. (Switzerland) Engineering problems imposed by the size of the 12 ft hydrogen bubble chamber are discussed. Size-induced operational problems, as well as those associated with the photographic and expansion systems are considered. (USA) A Tamosaitis, CERN Intern Colloquium on Bubble Chambers, Rep CERN-67-26.V.2, Aug 1967, 493-500 (Sci Tech Aerospace Reps, 6 (8), 1159, N68-18161). 33 : 30 1494. High resolution electron microscopy of biological specimens. (USA) Improved instrumentation and specimen preparation techniques are briefly described for ultrastructural studies of biological systems with high resolution electron microscopy. Improved specimen preparation techniques discussed include systematic use of ultrathin carbon RIO

films prepared by evaporation in ultrahigh vacuum on s supports. H Fernandez-Moran, Rep NASA-CR-76632, 1966, 8 pages (St', Aerospace Reps, 6 (9), 1284, N68-19222). 1495. The production of 15 /~m liquid hydrogen droplets. ( Britain) Liquid hydrogen droplets have been produced with an app,' incorporating a piezocrystal. The system is described. Droplets average diameter of 15 /~m were obtained, the average scat diameter being less than 50 per cent. B A Powell and C D King, J Sci Instrum, Ser 2, 1 (6), 1968, 670-( 1496. A high-temperature vacuum sample holder for the I~ camera. (Great Britain) A furnace is described which is used for small-angle x-ray scat studies of samples in vacuum at temperatures up to 450~C. Pro' has been made for heating and cooling the specimen at rates as as 200°C rain i between any two temperatures within the ope~ range. The sample holder could also be used for studies at ten tures down to -170°C. (USA) R W Gould and R W Hendrieks, J Sci Instrum, Set 2, 1 (6), 196[ 1497. Mass-spectrometric study of photoionization. IX. Hy¢ cyanide and acetonitrile. (USA) Photoionization yield curves are obtained from threshold to 6 for the HCN ~ and CN + ions of HCN and for the principal k CHaCN. The first ionization energy of HCN is 13.59 eV. Th dynamic values are calculated. Measurements were made v windowless vacuum-ultraviolet monochromator-mass spectrol Ion-yield curves in the wavelength region from onset to about 9 were obtained by using a low-pressure hydrogen discharge as p source. The equipment used is described in a previous publicati which reference is made. Anon, J Chem Phys, 48 (10), May 1968, 4765-4768. 1498. A He3/He 4 dilution refrigerator for M6ssbauer experime very low temperatures. (Great Britain) A versatile cryostat for M6ssbauer-effect research at temperatu low as 0.03°K is described, For cooling, the apparatus us~ He3]He 4 dilution refrigerator principle. Both constructiona operational features of the cryostat are presented. (Finland) G J Ehnholm et al, Cryogenics, 8 (3), 1068, 136-142. 1499. Study of luminous flow ahead of a cylinder using an e] shock tube with a diaphragm. (Japan) The luminous flow region ahead of the cylinder in a high tempe1 and low density flow generated in an electric shock tube v diaphragm, was experimentally investigated. It was found th; relative thickness of the luminous flow region is not constar increases with the decrease in the body diameter. R MatsuzakL Japan J Appl Phys, 7 (4), 1968, 321-329.

34. HIGH ALTITUDE AND SPACE TECHNOLOGY 3, Lubrication of sliding and rolling element electrical contacts in va See abstract number 1463. 3. Vacuum test on instrument size gears. See abstract number 150" 1500. Determination of the simulated solar flux incident on a craft in a test chamber. (USA) The report describes the method of calculating the incident sola impinging on the skin of a satellite of any shape under cond occurring in a thermal vacuum chamber. No account is taken, effect of reflections. M Toussaint, Rep ESRO-TM-II, July 1967, 57 pages (Sci Aerospace Reps, 6 (7), 982, N68-16555). 1501. Design and performance of two vacuum chambers and simulators for solar-cell research. (USA) A facility containing a 5-foot and a 2-foot diameter space-era mental chamber with two solar-radiation simulators and su equipment is described. The facility is designed for testing cc