1706. Spherical aberration of the stigmatic doublet of short quadrupole lenses

1706. Spherical aberration of the stigmatic doublet of short quadrupole lenses

Classified abstracts 1701-1714 32 1701. Some emittance measurements with a duoplasmatron ion source. ( Hollnnd) Measurements of the emittance of t...

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Classified

abstracts

1701-1714 32

1701.

Some emittance measurements with a duoplasmatron ion source. ( Hollnnd) Measurements of the emittance of the output beam of a duoplasmatron ion source are described. A typical set of parameters include: hydrogen pressure in the discharge chamber 10-l torr, discharge current 25 A, pulse length 50 microseconds, peak axial field 2 kG, extraction voltage 40 kV and beam current 140 mA. The effect of space charge on the measurements is discussed. It was found that space charge effects are significant in the beam emerging from the source, and that for meaningful measurements, narrow slits, 0.001 inch wide, should be used. H Wroe, Nucl lnstrum Methods, 52, (I), June 1967, 67-76. 32 1702. Technology of intense dc ion beams.

(USA)

The improvements achieved in the technology of intense dc ion beams, in the range 20-600 keV at currents of up to 1 A are discussed. Various ion sources are described dealing with the special problem occurring in this range: severe cooling, space charge, pulsed beams. Jon sources are described which are especially suited to proton production and to molecular ion production at source arc currents of up to 50 A. Single gap accelerating and focusing arrangements are described. 0 B Morgan et al, Rev Sci Instrum 38 (4), April 1967, 467480. 33. GENERAL PHYSICS

AND ELECTRONICS

33 : 30 Theoretical and experimental investigation of particle beams for the formation of thin films under vacuum. See abstract number 1683. 33 1703. Interaction of helical electron beams with a strong resonator electro-magnetic field at cyclotron frequency harmonics. (USSR) Problems connected with the interaction of a weakly-relativistic electron beam with the helical electron trajectory and with a strong resonator electromagnetic field of frequency very near to the cyclotron frequency harmonics, were solved by use of a digital computer. Diagrams for the cyclotron resonance masers efficiency and other typical parameters are given. G N Rapport et al, Radiotekh Elektron, 12 (4), April 1967, 633-641 (in Russian). 33 1704. Approximate method of calculation of charged particle intensive

curvilinear beams. (USSR) One differential equation of the second order is derived for calculations of curvilinear beams with charged particle trajectories identical to one of the aggregate of co-ordinate lines of an arbitrary orthogonal curvilinear system of co-ordinates. The problem is solved for beams where the effect of particle space charge cannot be neglected. N J Mikheev et al, Radiotekh Elektron, 12 (4), April 1967, 642-649 (in Russian). 33 1705. Field potential propagation in a space according to its given distribution on the axis. (USSR)

Approximate methods for determining the field potential from its distribution on the axis, used in practice in designing electrostatic lenses, are discussed with regard to their errors and one new method for computing the field potential at larger distances from the axis is given. G G Gurbanov et al, Radiotekh Elektron, 12 (4), April 1967, 659-661 (in Russian), 33 1706. Spherical aberration of the stigmatic doublet of short quadrupole lenses. (USSR)

Equations are derived for spherical aberration coefficients of the doublet of short quadrupole lenses in case of an astigmatic beam. A D Dymnikov et al, Radiotekh Elektron, 12 (4), April 1967, 662-667 (in Russian)

.

33 1707. On the focusing and dispersing properties of the field of a cylindrical capacitor. (USSR)

Motion of charged particles in the field of a cylindrical capacitor is analyzed and the use of the capacitor as a spectroscope, analyzing particles by their kinetic energy, is proposed. Particles are fed to the analyzer from the outer capacitor armature along the axis. A N Serebryanik and V E Kolker, Zh Tekh Fiz, 37 (5), May 1967, 922-926 582

(in Russian).

33 1708. Method of calculation of the inner structure of nonlaminar intensive plane beams of charged particles. (USSR)

A method is given for calculation of the crosswise distribution of the current density and velocity of electrons in nonlaminar plane beams taking into account the space charge effect and electron thermal velocities. The case when the electron thermal velocities may be neglected is analyzed in detail. V S Kuznetsov, Zh Tekh Fir. 37 (5), May 1967, 932-941 (in Russian). 33 1709. Experimental study of an ion source for electromagnetic separation with a view to high etliciency operation. (Ho/land)

isotope

A conventional ion-source with minor modifications was systematically investigated to determine the role of each of its parameters: cathode temperature, arc voltage, magnetic field, gas pressure, etc. The ultimate aim was the attainment of high efficiency operation, preserving an acceptable beam quality (line resolution). A practical method for the optimal adjustment of the various source parameters was developed. Using a cathode of I mm diameter, efficiency values of 30, 68 and 42 per cent, measured at the emission slit, were obtained for argon, xenon and mercury respectively. J Chavet and R Bemas, Nucl Instrum Methods, 51, (1) May 1967, 77-86. 33 1710. A low temperature sample holder with two degrees of freedom and a new method of measuring anisotropic susceptibilities. (Great Britain)

A low temperature sample holder is described which can hold samples of length nearly that of the inner diameter of a surrounding solenoid magnet and which permits sample rotation in any position. H H van Mal, J Sci Znstrum, 44 (6), June 1967, 446. 34. HIGH ALTITUDE

AND SPACE TECHNOLOGY

34 1711. Vacuum chamber heat-transmission analysis. (USA) An analytical investigation was conducted to study the effect of the test chamber pressure level on the accuracy of deep-space heat transfer simulation, using as parameters the test vehicle emittance and surface temperature. The study reveals that, with the exception of extremely low temperature conditions, a test chamber pressure of approximately 1OF torr provides the best thermal simulation. W W Guy and W E Ellis, Rep NASA-TM-X-1355, Feb 1967 (NASA, Manned Spacecraft

Centre, Houston,

Texas). 34

1712. Experience

in using a vacuum chamber for testing accurate mirrors of astronomical instruments. (USA) Various methods of testing fine optics are discussed, in relation to the difficulties created by optical heterogeneities of the air in the test facility. Details are given on a vacuum chamber technique for testing flat mirrors up to 500 mm diameter. This method succeeded in eliminating air streams, heat transmission through convection and direct ray emission. V A Savin, Rep FTD-TT-65-1537; TT-66-62517; AD-641106 (Air Force

Systems

Command,

36. DRYING, DEGASSING

Wright-Patterson

AFB, Ohio).

AND CONCENTRATION

36 1713. Vacuum dryer. (Germany) Suitable for the drying of tanned hides the device consists of a heated rigid under-plate and a box lid which rides up and down to seal tight to the plate and form an evacuated chamber round the hide with a layer of resilient air-permeable material placed on top of this. An endless metal belt between lid and plate is thermally connected to the plate and is advanced in steps to carry the hides for drying. The lid rises and falls in time with the belt steps and is divided into sectors which are lowered onto the hides arriving on the belt and form mutually partitioned chambers with individually adjustable vacuum rating. P Bocciardo, German Patent 1,241,937, Patent Abstr, 7 (28) part G, 19th July 1967, 2. 37. METALLURGY,

INORGANIC

CHEMISTRY,

ANALYTICAL

CHEMISTRY 37 1714. Creep at elevated temperatures and high vacuum. (USA) Creep tests in high vacuum and elevated temperatures were made on