William R. Baker

A Focusing Device for the External 350‐Mev Proton Beam of the 184‐Inch Cyclotron at Berkeley

A device has been constructed to focus the external beam of the 184‐in. cyclotron at Berkeley. The device consists of a cylindrical tube 4 ft. in length and 3 in. in diameter, which contains a longitudinal arc of nearly uniform current density. Such a device will focus any beam of cylindrical symmetry. Owing to the large power requirements of such a device it is applicable only to very short pulsed beams.

A diastereoselective synthesis of pseudo-C2 -symmetric 1,3-diamino-2-propanols as core units in HIV protease inhibitors

Abstract Inhibitors of HIV-1 protease are effective against the proliferation of HIV-1 infection in vitro. Based on the inherent symmetry of the protease homodimer, C 2 -symmetric and pseudo- C 2 -symmetric inhibitors have been designed, synthesized, and demonstrated to be potent inhibitors of HIV-1 protease and effective in arresting the spread of HIV-1 in vitro. We now report a novel synthesis of the pseudo- C 2 -symmetric 1,3-diamino-2-propanol core unit 12 , the key subunit in such HIV-1 protease inhibitors. Alkylation of the dianion of the N-Boc hydroxylactam 1–3 is highly diastereoselective and provides 4 in moderate to good yield. Imide ring opening, Curtius rearrangement, and deprotection lead to the desired diamino alcohol core unit 12 . A number of substituents, aromatic and heteroaromatic, were included in the R 1 and R 2 side chains.

The design and synthesis of cyclic renin inhibitors

Abstract A prototype cyclic renin inhibitor was designed through a combined effort between Discovery and Computer Aided Molecular Design. Synthesis of the prototype structure provided compounds which showed weak inhibitory activity of the enzyme renin.

Organic reactions at high pressure. The Diels-Alder reaction of p-benzoquinone with dienic esters

Abstract The Diels-Alder reaction of p -benzoquinone with substituted dienoic esters affords good yields of 4a,5,8,a-tetrahydro-1,4-naphthalenediones, free from the isomeric hydroquinone. The reactions were conducted at room temperature under 15 kbar (1.5 GPa) pressure in dichloromethane solutions.

Production of a Hot Rotating Plasma

The design and operation of Homopolar V are described. The device was designed so that there would be no driftvelocity (or voltage) limit as had been encountered in earlier experiments. Experiments with the device show that rotating plasmas need not suffer from a serious velocity limit, at least. at early times, and the discharge seems capable of producing a dense plasma with ion energies of thermonuclear interest, at least transiently. (L.T.W.)

High‐Voltage, Low‐Inductance Switch for Megampere Pulse Currents

A switch is described that will handle pulse currents of several millions of amperes and stand off dc supply voltages of over thirty kilovolts. It is useful in powering fast pinch devices such as those used in thermonuclear research.

Devices for generating highly-ionized hydrogen plasma

A set of closely-related devices for generating a highly-ionized hydrogen plasma is described. In each device a hydrogen plasma is created in a cylindrical tube immersed in an axial magnetic field of from 4 to 20 kG. The plasma is formed by a switch-on ionizing wave, driven from an external capacitor bank. In a typical tube 14.6 cm dia. and 86.4 cm long, with a magnetic field of 15 kG, an ion density of > 5 × 1015 cm-3 is attained in hydrogen of initial atomic density 6.6 × 1015 cm-3. The temperature of this plasma is between 10,000 and 30,000°K, and the plasma decays in several hundred microseconds by a volume-recombination process.

Apparatus for producing laser targets of 50 μ deuterium pellets

Apparatus is described which produces 50 μ deuterium pellets that are being used in a laser produced plasma facility. The pellets are sliced from a continuously spun solid deuterium thread at a rate of up to 10 pellets/sec. The methods of thread production and slicing, and pellet collimation are discussed. A unique feature of the apparatus is that it uses no liquid helium.

BOUNDARY EFFECTS IN VISCOUS ROTATING PLASMAS

The problem of current continuity and viscous drag at the boundaries in rotating‐plasma experiments is discussed. We particularly emphasize a hypothetical model having a steady state with axial symmetry; it is shown that the discharge impedance derived from this model does not agree with many observations. The ``Homopolar III experiment is described in which the flux surfaces were strongly convex and parallel to the toroidal‐shaped electrodes. In this way, friction at the insulators was reduced. But the structure of the discharge deviated drastically from axial symmetry near the outer surface. Several studies led to the conclusion that the flow pattern probably involved secondary flows. It was also found that the rotational speed could not be raised above a few cm/μsec because the insulators failed in spite of the special design of the experiment.

THE EFFECT OF CAPACITIVE STORED ENERGY ON NEUTRAL BEAM ACCELERATOR PERFORMANCE

The results of tests to determine the effects of capacitive stored energy (1/2 CV) on the performance of neutral beam injectors are reported. Typical fault current waveforms and methods to limit fault current are presented. Tests indicate that deterioration of performance is not only a function of peak stored energy but is also dependent on peak current and the characteristics of the breakdown.