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Determination of the beta energy (E/sub max/) using thin window instruments (open access)

Determination of the beta energy (E/sub max/) using thin window instruments

The use of simple survey instruments for beta-energy analysis is complicated by large differences that exist in the beta spectra shapes. These spectral shapes are often complex and change continuously as the betas are absorbed in air. Changes are also caused by absorbing material between the source and the detector. One may frequently encounter a combination of beta energies, either from multiple emissions from a single isotope or from several isotopes in the sample being evaluated. There may also be monoenergetic conversion electrons present in the sample or low-energy X rays which are absorbed in a similar fashion to betas. Obviously, a complete analysis of compelx beta spectra cannot be performed using only survey instruments. We present two methods which will give the approximate E/sub max/ of the beta energy responsible for the most significant portion of the beta dose. Either technique should give adequate information about the beta spectra to provide necessary guidance for the health physics evaluation of the exposure.
Date: August 12, 1983
Creator: Hankins, D.E.
System: The UNT Digital Library
Recent results from the PEP4-TPC on quark fragmentation (open access)

Recent results from the PEP4-TPC on quark fragmentation

The physics goals for the PEP-4/PEP-9 experiment concentrate on two areas: the fragmentation properties of quarks and gluons produced in e+e- annihilation, and the investigation of hadron production in 2-photon collisions. Only the first of these topics is addressed. Despite the many successes of QCD in the description of deep inelastic reactions, the basic fragmentation process of quarks and gluons is not very well understood. This lack of knowledge has been shown to jeopardize precise test of QCD, such as the accurate determination of the strong coupling constant. With its ability to disentangle complex hadronic events and to identify most of the final state particles, the TPC allows new and more sensitive tests of fragmentation models. A brief description of the detector is given and particle identification by ionization energy loss is described. Next, the inclusive production of stable hadrons and of resonances is discussed, and limits on the inclusive production of fractional charged particles are given. A new analysis of long-range correlations in e+e- annihilation is given.
Date: November 12, 1983
Creator: Hofmann, W.
System: The UNT Digital Library
Large aperture optical switching devices (open access)

Large aperture optical switching devices

We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs.
Date: December 12, 1983
Creator: Goldhar, J. & Henesian, M.A.
System: The UNT Digital Library
Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment (open access)

Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment

The gas inventory of the Tandem Mirror Experiment Upgrade (TMX-U) must be carefully controlled, if it is to successfully create various plasma configurations for thermal-barrier experiments designed to provide an improved performance for tandem-mirror experiments. This paper is a progress report on the calibration methods and pressure measurements of machine conditions deriving from recently improved neutral-beam gas control, and changes to the internal baffling geometry and the gettering system.
Date: August 12, 1983
Creator: Calderon, M. O.; Hunt, A. L.; Lang, D. D.; Nexsen, W. E.; Pickles, W. L. & Turner, W. C.
System: The UNT Digital Library
Silicon switch development for optical pulse generation in fusion lasers at Lawrence Livermore National Laboratory (open access)

Silicon switch development for optical pulse generation in fusion lasers at Lawrence Livermore National Laboratory

We have been developing a silicon photoconductive switch for use as a Pockels cell driver in the pulse generation systems of the fusion lasers Nova and Novette. The objective has been to make 10 kV switches repeatably and which are reliable on an operating system. We found that nonlinear phenomena in nearly intrinsic silicon caused excessive conduction at high voltage resulting in breakdown. Our experiments with doped material show that this problem can be eliminated, resulting in useful devices.
Date: July 12, 1983
Creator: Wilcox, R. B.
System: The UNT Digital Library
Reconnection in Spheromak formation and sustainment (open access)

Reconnection in Spheromak formation and sustainment

The Spheromak is a magnetic confinement device that is being explored in both the US and Japanese fusion programs. It is a member of the Compact Torus family of magnetic structures characterized by a set of closed, nested toroidal flux surfaces but without any coils, transformer cores, etc. protruding through the hole in the torus. The Speromak is closely elated to the Reversed Field Pinch (RFP) in that most of the magnetic field is produced by plasma currents flowing along the magnetic field lines (a near force free field) rather than by external coils. The Spheromak has magnetic field components of comparable strength in both the toroidal (azimuthal) and poloidal (in the plane perpendicular to the azimuthal unit vector) directions. The large internal magnetic energy in the Spheromak makes it rich in magnetohydrodynamic phenomena and reconnection, in particular, plays an important role in the formation, resistive decay and instability processes.
Date: December 12, 1983
Creator: Hammer, J. H.
System: The UNT Digital Library
Design and construction of the vacuum vessel for the tandem Mirror Fusion Test Facility (open access)

Design and construction of the vacuum vessel for the tandem Mirror Fusion Test Facility

We have designed the MFTF-B vacuum vessel both to maintain the required vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. The design calculations were greatly aided by computer models, which also speeded our redesign effort when the machine configuration was changed to the Axicelll MFTF-B this past year. Our field construction and erection effort should meet the July 1984 completion date for the vacuum vessel.
Date: August 12, 1983
Creator: Gerich, J.W.
System: The UNT Digital Library
Flywheel rotor and containment technology development, FY83 (open access)

Flywheel rotor and containment technology development, FY83

The Department of Energy decided to terminate the Flywheel Rotor and Containment Technology Development project during FY 1983. Activities this year included fabrication, inspection, and test evaluation of rotor and containment structures. A peak energy of 700 Wh was stored at an energy density of 70 Wh/kg. In cyclic tests, 10,000 cycles from design speed to half speed were logged without failure. The first test of a lightweight containment structure indicates the need for additional development. In complementary studies, production cost estimates were made for three flywheel designs. In a cooperative program with the University of Wisconsin, work began on construction of a flywheel/continuously variable transmission/heat engine car which promises fuel economy improvements of up to 100%. Suggestions are made for the direction of future work when interest in flywheel system reappears.
Date: September 12, 1983
Creator: Mohr, P. B. & Walter, C. E.
System: The UNT Digital Library
Line-coincidence schemes for producing laser action at soft-x-ray wavelengths (open access)

Line-coincidence schemes for producing laser action at soft-x-ray wavelengths

Line-coincidence schemes for producing laser action in the wavelength regime 100-30A are reviewed. Schemes involving pumping of 2..-->..4 transitions in neon-like ions are singled out as particularly attractive.
Date: January 12, 1983
Creator: Chapline, George F.
System: The UNT Digital Library
A Pyrovidicon-based Inspection System for Nuclear Reactor Safety (open access)

A Pyrovidicon-based Inspection System for Nuclear Reactor Safety

At the Savannah River Nuclear Facility irradiated assemblies are conveyed through the air from the reactor to a discharge/entry channel, where they are immersed in water. This paper addresses the monitoring of the temperature of these assemblies while they are in transit during the discharge cycle. To accomplish this, a remotely controlled and monitored radiation-hardened thermal imaging and alarm system was installed at each reactor. The paper will discuss the system concept and operation. The program for radiation hardening and testing this equipment will be reviewed.
Date: October 12, 1983
Creator: Lynam, E.C.
System: The UNT Digital Library