Diode-pumped Yb:Sr{sub 5}(PO{sub 4}){sub 3}F laser performance (open access)

Diode-pumped Yb:Sr{sub 5}(PO{sub 4}){sub 3}F laser performance

The performance of the first diode-pumped Yb{sup 3+}-doped Sr{sub 5}(PO{sub 4}){sub 3}F (Yb:S-FAP) laser is discussed. We found the pumping dynamics and extraction cross-sections of Yb:S-FAP crystals to be similar to those previously inferred by purely spectroscopic techniques. The saturation fluence for pumping was measured to be 2.2 J/cm{sup 2} using three different methods based on either the spatial, temporal, or energy transmission properties of a Yb:S-FAP rod. The small signal gain implies an emission cross section of 6.0 x 10{sup -20} cm{sup 2} that falls within error bars of the previously reported value of 7.3 x 10{sup -20} cm{sup 2}, obtained from spectroscopic techniques. Up to 1.7 J/cm{sup 3} of stored energy density was achieved in a 6 x 6 x 44 mm Yb:S-FAP amplifier rod. An InGaAs diode array has been fabricated that has suitable specifications for pumping a 3 x 3 x 30 mm Yb:S-FAP rod. In a free running configuration diode-pumped slope efficiencies up to 43% were observed with output energies up to {approximately}0.5 J per 1 ms pulse. When the rod was mounted in a copper block for cooling, 13 W of average power was produced with power supply limited operation at 70 Hz and …
Date: March 17, 1995
Creator: Marshall, C. D.; Payne, S. A. & Smith, L. K.
Object Type: Article
System: The UNT Digital Library
Feature test report for the Small Debris Collection and Packaging System (open access)

Feature test report for the Small Debris Collection and Packaging System

The Spent Nuclear Fuel Equipment Engineering group performed feature testing of the Small Debris Collection and Packaging System (SDCPS) in the 305 Cold Test Facility from January 30, 1995, to February 1, 1995. Feature testing of the Small Debris Collection and Packaging System (SDCPS) was performed for the following reasons: To assess the feasibility of using ``drop-out`` vessels to collect small debris (<2.5 cm) in MK-II fuel canisters while transferring sludge to the Weasel Pit. To evaluate system performance under conditions similar to those in the K-Basins (e.g. submerged under 4.9 meters of water and operated with long handled tools) while using a surrogate sludge mixed with debris. To determine if canister weight could be used to predict the volume of sludge and/or debris contained within the canisters during system operation.
Date: March 17, 1995
Creator: Brisbin, S. A.
Object Type: Report
System: The UNT Digital Library
Impact of atmospheric turbulence on Van Cittert-Zernike speckle cell area estimates (open access)

Impact of atmospheric turbulence on Van Cittert-Zernike speckle cell area estimates

Simulations of laser beam propagation at 3.5 microns wavelength through atmospheric turbulence are used to characterize on-target irradiance profiles and the Van Cittert-Zemike speckle cell areas associated therewith. Results for a 3 km horizontal path with C{sub N}{sup 2} values between 2.5 {times} 10{sup {minus}14} and 5 {times} 10{sup {minus}13} m{sup {minus}2/3} are compared with those for a 20 km near-vertical slant path for a C{sub N}{sup 2} versus altitude with a near-ground value of 5 {times} 10{sup {minus}-13}m{sup {minus}2/3} and a Huffnagel-Valley type shape. The irradiance fluctuations for the slant path are much smaller than for the shorter horizontal path. The speckle cell area for the slant path is approximately the vacuum-path value; for the 3 km horizontal path it is at most 3 times the vacuum-path value.
Date: March 17, 1995
Creator: Morris, J. R.
Object Type: Article
System: The UNT Digital Library
Properties of transition metal-doped zinc chalcogenide crystals for tunable IR laser radiation (open access)

Properties of transition metal-doped zinc chalcogenide crystals for tunable IR laser radiation

The spectroscopic properties of Cr{sup 2+}, Co{sup 2+}, and Ni{sup 2+}-doped single crystals of ZnS, ZnSe, and ZnTe have been investigated to understand their potential application as mid-IR tunable solid-state laser media. The spectroscopy indicated divalent Cr was the most favorable candidate for efficient room temperature lasing, and accordingly, a laser-pumped laser demonstration of Cr:ZnS and Cr:ZnSe has been performed. The lasers` output were peaked at {approximately} 2.35 {mu}m and the highest measured slope efficiencies were {approximately} 20% in both cases.
Date: March 17, 1995
Creator: DeLoach, L.D.; Page, R.H. & Wilke, G.D.
Object Type: Article
System: The UNT Digital Library
Radioactive effluents in Savannah River. Summary report for 1993-1994 (open access)

Radioactive effluents in Savannah River. Summary report for 1993-1994

During 1993-1994, low-level radiometric studies of the Savannah River continued to distinguish between effluent contributions from Plant Vogtle and the Savannah River Site. Measurements of these radioactive effluents are of mutual interest to both institutions, as they can address abnormal trends before they become health and legal concerns. The Environmental Technology Section (ETS) has conducted radiometric studies of Plant Vogtle since late 1986, prior to its startup. The plant has two 1100 MWe pressurized water reactors developed by Westinghouse, Unit 1 started commercial operations in June 1987, and Unit 2 began in May 1989. During powered operations, ETS has routinely detected neutron-activated isotopes in controlled releases but all activities have been orders of magnitude below the DOE guide values and EPA/CFR levels. In 1993-1994, Vogtle effluents continued to contribute low activities to the river. The Vogtle release data and the ETS measurements have tracked well over the past eight years.
Date: March 17, 1995
Creator: Winn, Willard G.
Object Type: Report
System: The UNT Digital Library
Study of corrections to the geometrical factor in the space charge impedance for the IPNS upgrade (open access)

Study of corrections to the geometrical factor in the space charge impedance for the IPNS upgrade

Collective instabilities are an important consideration in the 2-GeV rapidly-cycling synchrotron (RCS) of the proposed 1-MW spallation neutron source upgrade due to the very high beam intensity of 1.04{times}10{sup 14} protons per pulse. Collective instabilities are intensity-dependent effects which arise due to the electromagnetic wake fields generated by the beam as it interacts with its surroundings. The interactions are characterized by the coupling impedance, which in the RCS is dominated by space charge effects. To minimize the space charge impedance, the vacuum chamber is constructed with a special wire rf shield. Estimating the longitudinal and transverse impedance due to space charge is critical for the beam stability analysis. The standard geometrical factors used to evaluate the space charge impedance assume a uniform, round, unbunched beam in a cylindrical, smooth beam pipe. Two corrections to the geometrical factors have been proposed to account separately for the wire rf-screening cage and the more realistic varying elliptical beam cross-section. These corrections are studied in the case of the RCS. It is found that including these details results in a correction of less than 20%.
Date: March 17, 1995
Creator: Harkay, K.C.
Object Type: Report
System: The UNT Digital Library
Tension in the tie-down chains of a shipping container for hazardous material (open access)

Tension in the tie-down chains of a shipping container for hazardous material

Chains are frequently used to tie the shipping containers of hazardous material to a truck bed. The tie-down system is nonlinear when the container is subjected to a triaxial force during transit. It is nonlinear because chains cannot carry compressive force, and the base of the container may partially lift off from the truck bed. A method was developed to calculate the amount of tension in the chains. This methodology includes three assumptions: (1) No friction exists between the container and the truck bed; (2) The container and the truck bed are rigid; and (3) All chains are properly tightened (i.e., no slacks) during preparation for shipment. The methodology employs an iterative process of a linear tie-down system. This linear system is derived from the nonlinear system with two additional assumptions: (a) All chains can carry compression as well as tension; and (b) There is a point contact between the container and the truck bed. This linear system has a closed-form solution. After the first solution of the linear system is obtained, the unreasonable, or physically impossible, rotational degree of freedom of the container and the chains with compressive force are eliminated in the follow-up iterative calculations using the same …
Date: March 17, 1995
Creator: Lo, T.Y.
Object Type: Report
System: The UNT Digital Library
Underground measurements of seismic vibrations at the SSC site (open access)

Underground measurements of seismic vibrations at the SSC site

The results of underground measurements of seismic vibrations at the tunnel depth of the Superconducting Super Collider (SSC) site are presented. Spectral analysis of the data obtained in the frequency band from 0.05 Hz to 1500 Hz is performed. It is found that amplitudes of ambient ground motion are less than requirements for the Collider, but cultural vibrations are unacceptably large and will cause fast growth of transverse emittance of the SSC beams.
Date: March 17, 1995
Creator: Shiltsev, V.D.; Parkhomchuk, V.V. & Weaver, H.J.
Object Type: Report
System: The UNT Digital Library
WRAP Module 1 data management system (DMS) software design description (SDD) (open access)

WRAP Module 1 data management system (DMS) software design description (SDD)

The Waste Receiving and Processing (WRAP) Module 1 Data Management System (DMS) System Design Description (SDD) describes the logical and physical architecture of the system. The WRAP 1 DMS SDD formally partitions the elements of the system described in the WRAP 1 DMS Software requirements specification into design objects and describes the key properties and relationships among the design objects and interfaces with external systems such as the WRAP Plant Control System (PCS). The WRAP 1 DMS SDD can be thought of as a detailed blueprint for implementation activities. The design descriptions contained within this document will describe, in detail, the software products that will be developed to assist the Project W-026, Waste Receiving and Processing Module 1, in their management functions. The WRAP 1 DMS is required to collect, store, and report data related to certification, tracking, packaging, repackaging, processing, and shipment of waste processed or stored at the WRAP 1 facility.
Date: March 17, 1995
Creator: Talmage, P.A.
Object Type: Report
System: The UNT Digital Library