Neutron generation in a sealed direct-acceleration tube with a laser-plasma anode

Experiments have been performed on neutron generation in small sealed tubes with laser-plasma ion sources. The nuclear reaction T(d, n)He⁴ has been employed with a laser frequency of 12.5 Hz in producing an output of 5 · 10⁹ n/sec. It is shown that efficient neutron generation is possible for laser pulse energies at the 10^–2 J level.Translated from Izvestiya Vysshyh Uchebnykh Zavedenii, Fizika, No. 11, pp. 6–10, November, 1981.We are indebted to Yu. A. Bykovskii, D. F. Bespalov, K. I. Kozlovskii, and A. Z. Mints for valuable advice and assistance.     

Neutron generation in small sealed accelerating tubes

The basic physical principles of neutron generation in sealed accelerating tubes, whose radius, as rule, does not exceed 10 cm, are examined. The results of the latest studies and developments of the main types of such tubes — gas-filled and vacuum — are systematized. The prospects for the development of efficient neutron tubes based on the use of a laer ion source, collective methods for accelerating ions, and also high-current pulsed discharges are discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 3–31, August, 1985.     

Neutron Diagnostics for Deuteron Flows from Pulsed Plasma Formations in a Magnetic Field

A diagnostic procedure establishing a relation between the energy of a laser pulse W (0.1 ≤ W ≤ 0.8) and the number of deuterons N _d extracted from the laser plasma in a vacuum accelerating diode with magnetic isolation of electrons is presented. The diagnostics is based on the measurement of neutrons generated at a target, which is a part of the ion collector at the same time. The results of experimental research and numerical modeling for the accelerating voltage at a diode interval up to 400 kV are presented.     

Control of parameters of micropinches formed in current-carrying plasma jet

The temporal evolution and spatial pattern of X-ray emission from a laser-induced vacuum discharge of moderate power has been investigated. It was found that micropinches in the initial stage of the cathode jet expansion into the vacuum ambient were formed. They generated a soft X-ray radiation and beams of accelerated electrons; therewith these phenomena occurred just when both amplitude of the discharge current and energy of the initiating laser pulse lied in the specified ranges of values. Parameters of the micropinch, namely, its position within the interelectrode gap and also, intensity of the X-ray radiation and beams of the accelerated electrons emitted from the micropinch are variable over a wide range of values through changes of energy of the laser pulse and/or amplitude of the discharge current.     

Model for Generation of Neutrons in a Compact Diode with Laser-Plasma Anode and Suppression of Electron Conduction Using a Permanent Cylindrical Magnet

A model for acceleration of deuterons and generation of neutrons in a compact laser-plasma diode with electron isolation using magnetic field generated by a hollow cylindrical permanent magnet is presented. Experimental and computer-simulated neutron yields are compared for the diode structure under study. An accelerating neutron tube with a relatively high neutron generation efficiency can be constructed using suppression of electron conduction with the aid of a magnet placed in the vacuum volume.     

Dynamics of high-temperature plasma formation during laser irradiation of three-dimensionally structured,low-density matter

Results are presented from an experimental investigation of the properties of the plasma produced by the action of a radiation pulse at the second harmonic of a Nd laser, with average intensity ~5·10¹⁴ W/cm² in the focal spot, on flat targets consisting of porous polypropylene (CH)_x with an average density of 0.02 g/cm³ (close to the critical plasma density) and with ~50 μm pores. The properties of the laser plasma obtained with porous and continuous targets are substantially different. The main differences are volume absorption of the laser radiation in the porous material and much larger spatial scales of energy transfer. The experimentally measured longitudinal ablation velocity in the porous material was equal to (1.5–3)·10⁷ cm/s, which corresponds to a mass velocity of (3–6)·10⁵ g/cm²· s, and the transverse (with respect to the direction of the laser beam) propagation velocity of the thermal wave was equal to ~(1–2) ·10⁷ cm/s. The spatial dimensions of the plasma plume were ~20–30μm. The plasma was localized in a 200–400μm region inside the target. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 7, 462–467 (10 October 1996)     

Poly(ester anhydride)s prepared by the insertion of ricinoleic acid into poly(sebacic acid)

New degradable poly(ester anhydride)s were prepared by the melt polycondensation of diacid oligomers of poly(sebacic acid) (PSA) transesterified with ricinoleic acid. The transesterification of PSA with ricinoleic acid to form oligomers was conducted via a melt bulk reaction between a high molecular weight PSA and ricinoleic acid. A systematic study on the synthesis, characterization, degradation in vitro, drug release, and stability of these polymers was performed. Polymers with weight‐average molecular weights of 2000–60,000 and melting temperatures of 24–77 °C were obtained for PSA containing 20–90% (w/w) ricinoleic acid. NMR and IR analyses indicated the formation of ester bonds along the polyanhydride backbone. These new degradable copolymers have potential use as drug carriers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1059–1069, 2003     

Acceleration of deuterons in a spherical ion diode with a laser-plasma anode

A physical model is proposed for a spherical pulsed ion diode with a laser ion source consisting of a plasma anode which varies in size while the accelerating voltage is applied. A study of this process was conducted using computer analysis of the nonlinear differential equations that are proposed in the article. From the results of the computer experiment, acceleration characteristics of the deuterons are established for similar diodes, and the effect of diode geometries, temporal and electrical characteristics on the energy spectra of the deuterons, the current pulse shape, and the deuteron acceleration charge are studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 67–71, February, 1988.In conclusion, the author expresses a deep gratitude to A. S. Tsybin for discussing results achieved and for useful advice.