V. Zajic: Instrumental Corrections of Peak Areas in Gamma-ray Sum-peak Counting; International Journal of Applied Radiation and Isotopes 37, pp. 1225-1233, (1986). download (234 Kbytes)
Abstract - Direct activity measurement by the g-ray sum-peak methodwith two NaI(Tl) crystals operating in the summing, coincidence, and anticoincidence modes is demonstrated for 88Y and207Bi. Estimates of g-ray peak areas are described in detail. Instrumental corrections of the peak areas for pile-up, dead time, and random summing are derived theoretically and verified experimentally for all three modes of operation.
V. Zajic: A Simple Way of Varying the Source Efficiency for the Extrapolation Method in 4p(PC)-g Coincidence Counting; International Journal of Applied Radiation and Isotopes 38, pp. 549-552, (1987). download (96 Kbytes)
Abstract - A simple way of varying the source efficiency in 4p(PC)-g coincidence counting is described. A wet source is put into the 4p flow proportional counter and measured repeatedly; the 4p(PC) counting efficiency increases smoothly to a maximum value as the water evaporates. It is possible to reproduce the measurement with the same source by rewetting it. The method has been applied to more than 20 radionuclides and the accuracy of the extrapolation improved significantly.
P. Thieberger, E. G. Stassinopulos, O. Van Gunten, and V. Zajic: Heavy-ion beams for single-event research at Brookhaven - present and future; Nuclear Instruments and Methods B56/57, pp. 1251-1255, (1991). download (74 Kbytes)
Abstract - Since low energy nuclear physics research was discontinued at Brookhaven and replaced by a relativistic heavy ion program, large blocks of time became available at the tandem Van de Graaff facility for technological applications and for research in other areas. The main technological application has been the single event upset (SEU) testing of microelectronic devices, and this activity has given of methods used for satisfying these requirements at the Brookhaven facility. Available ion species, energies, ranges, LETs and beam intensities, purity and uniformity are discussed. Characteristics are summarized of a sophisticated and extremely user friendly test chamber and associated hardware and software installed at Brookhaven by a coalition of government agencies and made available for general use. The possibility is mentioned of extending SEU testing to higher energies by using heavy ion beams from a booster synchrotron now under construction and from the existing large alternating gradient synchrotron (AGS). Finally, a brief discussion is given of compatibility with other programs and of future availability of low and high energy heavy ions for SEU testing at Brookhaven.
V. Zajic and P. Thieberger: Heavy Ion Linear Energy Transfer Measurements During Single Event Upset Testing of Electronic Devices; IEEE Transactions on Nuclear Science 46, pp. 59-69, (1999). download (128 Kbytes)
Abstract - A heavy ion beam diagnostic system installed at the Brookhaven Single Event Upset Test Facility is described. Calibration of the system with the help of a-particles, essential for linear energy transfer (LET) measurements, is discussed. Measured LET values for 20 different ions, including
with energies between 0.5 and 8.5 MeV/AMU but not exceeding 400 MeV for the heaviest ions, are presented in both graphical and numerical forms. Results are compared to predictions of the TRIM-90 simulation program, with an average difference between the measured and calculated values of (2 ± 6)%.
P. Thieberger, A. L. Hanson, D. B. Steski, V. Zajic, S. Y. Zhang, and H. Ludewig: Secondary-electron yields and their dependence on the angle of incidence on stainless-steel surfaces for three energetic ion beams; Physical Review A61, 042901 (11 pp.), (2000). download (239 Kbytes)
Abstract - Secondary-electron yields were investigated for 28-MeV protons, 126-MeV oxygen ions, and 182-MeV gold ions incident on 304 stainless-steel surfaces. The dependence on the incidence angle was studied in detail, and a system was developed which allows accurate measurements to be performed over a wide angular range extending to nearly grazing collisions. Electron yield estimates of interest for future accelerator applications are developed for 1-GeV protons, and the possible mitigation of deleterious effects by using serrated rather than flat surfaces is analyzed.