Soft x-ray detection with diamond photoconductive detectors (open access)

Soft x-ray detection with diamond photoconductive detectors

Photoconductive detectors fabricated from natural lla diamonds have been used to measure the x-ray power emitted from laser produced plasmas. The detector was operated without any absorbing filters to distort the x-ray power measurement. The 5.5 eV bandgap of the detector material practically eliminates its sensitivity to scattered laser radiation thus permitting filterless operation. The detector response time or carrier life time was 90 ps. Excellent agreement was achieved between a diamond PCD and a multichannel photoemissive diode array in the measurement of radiated x-ray power and energy. 4 figs.
Date: May 4, 1990
Creator: Kania, D. R.; Pan, L.; Kornblum, H.; Bell, P.; Landen, O. N. & Pianetta, P.
Object Type: Article
System: The UNT Digital Library
Texas Register, Volume 15, Number 34, Pages 2535-2608, May 4, 1990 (open access)

Texas Register, Volume 15, Number 34, Pages 2535-2608, May 4, 1990

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: May 4, 1990
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Attorney General Opinion: LO90-21 (open access)

Texas Attorney General Opinion: LO90-21

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification; The circumstances under which a taxing unit may waive penalty and interest accruing on a delinquent tax account.
Date: May 4, 1990
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Fermilab Library Directions (open access)

Fermilab Library Directions

In this document, we indicate our current thinking about the directions of the Fermilab Library. The ideas relate to the preprint management issue in a number of ways. The ideas are subject to revision as we come to understand what is possible as well as what is needed by the Laboratory community. This document should therefore be regarded as our personal view--the availability of off-the-shelf technology, of funding as well as feedback from the laboratory community about their needs will all affect how far we actually proceed in any of these directions.
Date: May 4, 1990
Creator: Garrett, P. & Ritchie, D.
Object Type: Article
System: The UNT Digital Library
Stark-effect measurement of high FEL (free-electron laser) electric fields in MTX (Microwave Tokamak Experiment) by laser-aided particle-probe spectroscopy (open access)

Stark-effect measurement of high FEL (free-electron laser) electric fields in MTX (Microwave Tokamak Experiment) by laser-aided particle-probe spectroscopy

We are constructing a diagnostic system to measure the electric field (>100 kV/cm) of a free-electron laser (FEL) beam when injected into the plasma of the Microwave Tokamak Experiment (MTX). The apparatus allows a crossed-beam measurement, with 2-cm spatial resolution in the plasma, involving the FEL beam (with 140-GHz, {approx}1-GW ECH pulses), a neutral-helium beam, and a dye-laser beam. After the laser beam pumps metastable helium atoms to higher excited states, their decay light is detected by a collimated optical system. Because of the Stark effect due to the FEL electric field ({rvec E}), a forbidden transition can be strongly induced. The intensity of emitted light resulting from the forbidden transition is proportional to E{sup 2}. Because photon counting rates are calculated to be low, extra effort is made to minimize background and noise levels. It is possible that the lower {rvec E} of an MTX gyrotron-produced ECH beam with its longer-duration pulses also can be measured using this method. Other applications may include measurements of ion temperature (using charge-exchange recombination), edge-density fluctuations, and core impurity concentrations. 11 refs., 2 figs., 2 tabs.
Date: May 4, 1990
Creator: Oda, T.; Takiyama, K.; Odajima, K.; Ohasa, K.; Shiho, M.; Mizuno, K. et al.
Object Type: Article
System: The UNT Digital Library
Thomson scattering diagnostic for the Microwave Tokamak Experiment (open access)

Thomson scattering diagnostic for the Microwave Tokamak Experiment

The Thomson-scattering diagnostic system (TSS) on the Microwave Tokamak Experiment (MTX) at LLNL routinely monitors electron temperature (T{sub e}) and density. Typical measured values at the plasma center under clean conditions are 900 {plus minus} 70 eV and 1 to 2 {times} 10{sup 14} ({plus minus}30%) cm{sup {minus}3}. The TSS apparatus is compact, with all elements mounted on one sturdy, two-level optics table. Because of this, we maintain with minimum effort the alignment of both the ruby-laser input optics and the scattered-light collecting optics. Undesired background signals, e.g., plasma light as well as ruby-laser light scattered off obstacles and walls, are generally small compared with the Thomson-scattered signals we normally detect. In the MTX T{sub e} region, the TSS data are definitely fitted better when relativistic effects are included in the equations. Besides determining the temperature of the Maxwellian electron distribution, the system is designed to detect electron heating from GW-level free-electron laser (FEL) pulses by measuring large wavelength shifts of the scattered laser photons. TSS data suggest that we may indeed by able to detect these electrons, which can have energies up to 10 keV, according to computer simulation. 7 refs., 4 figs.
Date: May 4, 1990
Creator: Foote, J.H.; Barter, J.D.; Sewall, N.R.; Jolly, J.J. & Schlander, L.F.
Object Type: Article
System: The UNT Digital Library