19 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Calorimetric Dosemeters"  
Results: 1 - 19
open access

A cryogenic dose calorimeter for pulsed radiographic accelerators

Description: Calorimetry is the most direct, absolute technique for absorbed dose measurements. To improve the measurement accuracy for use with quantitative radiography, a calorimeter has been developed for LANL`s pulsed radiographic machines which produce Bremsstrahlung radiation fields of 50-200 Rad per pulse at 1 meter from the source. This paper describes the theory of operation, the calorimeter design, and presents results from the PHERMEX accelerator.
Date: October 1, 1994
Creator: Watson, S. A.; Kauppila, T. & Mueller, K. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Calorimetry

Description: The techniques and equipment currently employed for calorimetric dosimetry have been briefly surveyed and the status of some recent measurements presented. The problems which remain to be investigated are: the thermal defect, the suitability of A-150 plastic as a material for heavy charged particle calorimetry and calorimeter designs that are appropriate for specific radiation situations, including cryogenic calorimeters.
Date: January 1, 1978
Creator: McDonald, J. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Final Report: A Calorimeter for Neutron Flux Measurement

Description: A calorimeter for absolute neutron flux measurement has been built and tested. The calorimeter measures the heat produced in a 10{degrees}K thick LiPb target when neutrons are captured via the {sup 6}Li(n,{sup 3}H){sup 4}He reaction. The sensitivity achieved was 1.3x10{sup 6} n/s for a 1 hour measurement. Separate flux measurements with the calorimeter and a {sup 238}U fission chamber are in agreement and show that systematic errors are less than 3%. An improved calorimeter has been built which… more
Date: April 1, 1993
Creator: Chupp, T. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Twin-tube conduction radionuclide calorimeter

Description: The complete calorimeter system used to measure powers from 0.1 W to 2 W of samples 1.5 in. in diameter by 5 in. in length is described. Calorimeter readout is by digital voltmeter. A sensitivity of 1501 mV/W at 1.327 W with on accuracy of 99.9% was obtained. Sample equilibrium time is 4 h. The twin-tube temperature measurement system compensates for thermostat temperature fiuctuations. Thermistors measure the temperature gradient produced by heat flow through a 5-in. length of 1.75-in.-o.d., 0… more
Date: December 1, 1973
Creator: Rupert, G. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Biological and clinical dosimetry. Progress report, October 1, 1977--September 30, 1978

Description: The portable tissue equivalent plastic calorimeter has been employed for a number of studies including: measurements of neutron dose in therapeutic beams and the measurement of dose in photon and electron beams. Measurements of the thermal defect for A-150 plastic have been carried out using 1.7 and 4.0 MeV protons produced by the Brookhaven National Laboratory, Van de Graaf accelerator. Initial results do not indicate significant energy dependence and the values obtained so far are within abou… more
Date: January 1, 1978
Creator: Laughlin, J.S. & McDonald, J.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Calorimetric dosimetry in neutron and charged particle beams

Description: A portable tissue-equivalent (TE) calorimetric, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in several neutron radiotherapy fields. Comparisons of spherical, cylindrical, and thimble shaped TE ionization chambers have been carried out using either air, or a flow of TE gas in the chamber. (GHT)
Date: January 1, 1978
Creator: McDonald, J. C.; Ma, I. C. & Laughlin, J. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The large volume calorimeter for measuring the pressure cooker'' shipping container

Description: A precise, low wattage, large volume calorimeter system has been developed at Mound to measure two configurations of the 12081 containment vessel. This system was developed and constructed to perform verification measurements at the Savannah River Site. The calorimeter system has performance design specifications of {plus minus}0.3% error above the 2-watt level, and {plus minus}(0.03% plus 0.006 watts) at power levels below 2 watts (one sigma). Data collected during performance testing shows me… more
Date: January 1, 1991
Creator: Kasperski, P.W.; Duff, M.F.; Wetzel, J.R. (EG and G Mound Applied Technologies, Miamisburg, OH (United States)); Baker, L.B. & MacMurdo, K.W. (Westinghouse Savannah River Co., Aiken, SC (United States))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The dry heat exchanger calorimeter system

Description: A radiometric isothermal heat flow calorimeter and preconditioner system that uses air instead of water as the heat exchange medium has been developed at Mound. The dry heat exchanger calorimeter is 42 inches high by 18 inches in diameter and the preconditioner is a 22 inch cube, making it extremely compact compared to existing units. The new system is ideally suited for transportable, stand-alone, or glovebox applications. Preliminary tests of the system have produced sample measurements with … more
Date: January 1, 1991
Creator: Renz, D. P.; Wetzel, J. R.; James, S. J.; Kasperski, P. W. & Duff, M. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Investigations into the thermal defect of tissue-equivalent plastic. [A-150]

Description: The thermal defect, defined as the fraction of absorbed radiation energy which is not converted to heat energy in the calorimetric dosimetry absorber was investigated for A-150 tissue-equivalent plastic. Studies to measure the thermal defect as a function of proton energy and for various energies of alpha particles and the heavy recoil nuclei produced in tissue by neutrons are proposed along with a proposal to compare the thermal defects of A-150 plastic obtained from different laboratories and… more
Date: January 1, 1976
Creator: Goodman, L. J. & McDonald, J. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Calorimetric and ionometric dosimetry for cyclotron produced fast neutrons

Description: A portable tissue equivalent (TE) calorimeter, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in two fast neutron fields produced by the /sup 9/Be(/sup 3/He,n) and /sup 9/Be(d,n) interactions. A disc shaped ionization chamber has also been constructed of A-150 plastic and has a collecting volume geometrically equivalent to the calorimeter core (2 cm in diameter and 0.2 cm thick). A flow of methane compounded TE gas was maintained through the chamber at a ra… more
Date: January 1, 1977
Creator: McDonald, J. C.; Ma, I. C. & Laughlin, J. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fast-response cryogenic calorimeter containing a 52-KG radiation absorber. [To measure fission product radiation from 60 mg /sup 235/U foils irradiated in reactor]

Description: An isothermal liquid helium boiloff calorimeter containing a 52-kg copper radiation absorber, and having a time constant < 1sm was built to measure fission product beta and gamma radiation from 60-mg /sup 235/U foils irradiated in a nuclear reactor. The short response time was achieved by the large reduction in heat capacity of solids at 4/sup 0/K, and by nearly isothermal operation. Though the initial power level was approx.3 W, the maximum thermal energy storage was approx.1 joule. The Al cla… more
Date: January 1, 1977
Creator: Bendt, P. J. & Yarnell, J. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Biological and clinical dosimetry. Progress report, October 1, 1980-September 30, 1981

Description: A second measurement of the event size distribution for 20 MeV neutrons was carried out at Ohio University to determine the reproducability of results. Again a significant difference between measurement and theoretical calculations by Caswell and Coyne was found. The measured fraction of events due to alpha particles was significantly lower than that predicted by the calculation of Casell and Coyne. Furthermore, the discrepancies with the theoretical calculations made by Caswell and Coyne were … more
Date: September 30, 1981
Creator: Laughlin, J. S. & Zeitz, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experience with a double-compensating beam calorimeter

Description: In an experiment to measure the D(t,..cap alpha..)n cross section at beam energies of 10 to 120 keV, we have developed a double-compensating beam calorimeter, based on a Swiss design to measure the partical beam intensity. A Faraday cup is not useful because of considerable charge exchange in the target gas at such low beam energies. We calibrated the calorimeter both with 10- and 3-MeV protons (comparing with a Faraday-cup measurement of the beam flux) and with the heat generated in a precisio… more
Date: January 1, 1982
Creator: Jarmie, N.; Brown, R.E.; Hardekopf, R.A. & Martinez, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Biological and clinical dosimetry. Progress report July 1, 1964-June 30, 1979

Description: The dosimetric studies at this laboratory were initiated with the primary goal of developing systems for the determination of absorbed dose in biological research and clinical applications. The primary method under study is the local absorbed dose calorimeter, a concept initiated and developed by J. S. Laughlin. In addition, secondary dosimetric systems such as ionization chambers, chemical dosimeters and thermoluminescent dosimeters (TLD) are being developed and applied to provide an absolute … more
Date: September 1, 1979
Creator: Laughlin, J.S. & McDonald, J.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Electron energy and charge albedos - calorimetric measurement vs Monte Carlo theory

Description: A new calorimetric method has been employed to obtain saturated electron energy albedos for Be, C, Al, Ti, Mo, Ta, U, and UO/sub 2/ over the range of incident energies from 0.1 to 1.0 MeV. The technique was so designed to permit the simultaneous measurement of saturated charge albedos. In the cases of C, Al, Ta, and U the measurements were extended down to about 0.025 MeV. The angle of incidence was varied from 0/sup 0/ (normal) to 75/sup 0/ in steps of 15/sup 0/, with selected measurements at … more
Date: November 1, 1981
Creator: Lockwood, G. J.; Ruggles, L. E.; Miller, G. H. & Halbleib, J. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen