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Optimization of electrochemical-etching parameters for highly sensitive CR-39 fast neutron dosimeters

Description: Voltage gradient and frequency were studied for their influence on the electrochemical etching of CR-39 plastic irradiated with fission spectrum, fast neutrons. A power supply having outputs of up to 1.5 kV (rms) and 5 kHz was used. Differential leakage current measurements under non-etching conditions indicated that the optimal values in electrochemical etching would be 20 kV/cm and 1.3 kHz. That these parameters produced a maximum sensitivity was verified in subsequent electrochemical etching experiments with foils that were both unirradiated and irradiated. The introduction of a proton irradiator cover and a conventional etching step prior to the electrochemical etching, increased the sensitivity to neutrons (approx. 30-fold) and decreased the background track density to 4.4 +- 0.6 tracks/cm/sup 2/. The corresponding sensitivity was then 1.3 tracks/cm/sup 2//mrem with a minimum level of detectability (3sigma) of 1.4 mrem.
Date: January 1, 1981
Creator: Gammage, R.B. & Chowdhury, A.
Partner: UNT Libraries Government Documents Department

Small-angle neutron scattering at pulsed sources compared to reactor sources

Description: Detailed comparisons of measurements made on small-angle neutron scattering instruments at pulsed spallation and reactor sources show that the results from the two types of instruments are comparable. It is further demonstrated that spallation instruments are preferable for measurements in the mid-momentum transfer domain or when a large domain is needed. 8 refs., 2 figs.
Date: January 1, 1990
Creator: Hjelm, R.P. Jr.; Seeger, P.A. (Los Alamos National Lab., NM (USA)) & Thiyagarajan, P. (Brookhaven National Lab., Upton, NY (USA))
Partner: UNT Libraries Government Documents Department