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Advanced concepts in accelerator timing control

Description: The control system for the Booster accelerator presently under construction at BNL includes a timing section with serial high speed coded data distribution, computer based encoders for both real time and field driven clocks and a method of easily tracking the performance and reliability of these timing streams. We have developed a simple method for the generation of timing which operates to produce pulses which may be repeated as desired with minimal latency.
Date: January 1, 1988
Creator: Frankel, R. & Salwen, C.
Partner: UNT Libraries Government Documents Department

Long Range Active Detection of HEU Based on Thermal Neutron Multiplication

Description: We report on the results of measurements of proton irradiation on a series of targets at Brookhaven National Laboratory’s (BNL) Alternate Gradient Synchrotron Facility (AGS), in collaboration with LANL and SNL. We examined the prompt radiation environment in the tunnel for the DTRA-sponsored series (E 972), which investigated the penetration of air and subsequent target interaction of 4 GeV proton pulses. Measurements were made by means of an organic scintillator with a 500 MHz bandwidth system. We found that irradiation of a depleted uranium (DU) target resulted in a large gamma-ray signal in the 100-500 µsec time region after the proton flash when the DU was surrounded by polyethylene, but little signal was generated if it was surrounded by boron-loaded polyethylene. Subsequent Monte Carlo (MCNPX) calculations indicated that the source of the signal was consistent with thermal neutron capture in DU. The MCNPX calculations also indicated that if one were to perform the same experiment with a highly enriched uranium (HEU) target there would be a distinctive fast neutron yield in this 100-500 µsec time region from thermal neutron-induced fission. The fast neutrons can be recorded by the same direct current system and differentiated from gamma ray pulses in organic scintillator by pulse shape discrimination.
Date: May 24, 2010
Creator: L., Forman; I., Dioszegi; Salwen, C. & and Vanier, P.E.
Partner: UNT Libraries Government Documents Department

Application of Triple Coincidence for the Detection of Small Amounts of Special Nuclear Materials

Description: We constructed a device that measures two {gamma}-rays and one neutron from spontaneous fission and any resulting multiplication chains. It extends the associated particle technique based upon correlated counting of the multiplicity of gamma-rays and neutrons released in spontaneous- or neutron-induced fission. There are two advantages in incorporating a third detector in the design over the standard two-detector version. First, we found that random uncorrelated events dominate the background of coincident counting with a gamma-ray- and neutron-detector. These might be suppressed by requiring an additional coincidence. Second, the time history of gamma-ray emission between the two gamma-ray detectors is related to multiplication in the target media. Multiplication in highly enriched uranium is much greater than in depleted uranium.
Date: June 12, 2011
Creator: DIOSZEGI, I.; Salwen, C. & and Forman, L.
Partner: UNT Libraries Government Documents Department

Directional Stand-off Detection of Fast Neutrons and Gammas Using Angular Scattering Distributions

Description: We have investigated the response of a DoubleScatter Neutron Spectrometer (DSNS) for sources at long distances (gr than 200 meters). We find that an alternative method for analyzing double scatter data avoids some uncertainties introduced by amplitude measurements in plastic scintillators.Time of flight is used to discriminate between gamma and neutron events, and the kinematic distributions of scattering angles are assumed to apply. Non-relativistic neutrons are most likely to scatter at 45°, while gammas with energies greater than 2 MeV are most likely to be forward scattered. The distribution of scattering angles of fission neutrons arriving from a distant point source generates a 45° cone, which can be back-projected to give the source direction. At the same time, the distribution of Compton-scattered gammas has a maximum in the forward direction, and can be made narrower by selecting events that deposit minimal energy in the first scattering event. We have further determined that the shape of spontaneous fission neutron spectra at ranges gr than 110 m is still significantly different from thecosmic ray background.
Date: October 25, 2009
Creator: e., Vanier P.; Dioszegi, I.; Salwen, C. & Forman, L.
Partner: UNT Libraries Government Documents Department

A field-deployable gamma-ray spectrometer utilizing xenon at high pressure

Description: Prototype gamma-ray spectrometers utilizing xenon gas at high pressure, suitable for applications in the nuclear safeguards, arms control, and nonproliferation communities, have been developed at Brookhaven National Laboratory (BNL). These spectrometers function as ambient-temperature ionization chambers detecting gamma rays with good efficiency in the energy range 50 keV - 2 MeV, with an energy resolution intermediate between semiconductor (Ge) and scintillation (NaI) spectrometers. They are capable of prolonged, low-power operation without a requirement for cryogenic fluids or other cooling mechanisms, and with the addition of small quantities of {sup 3}He gas, can function simultaneously as efficient thermal neutron detectors.
Date: October 1, 1996
Creator: Smith, G.C.; Mahler, G.J.; Yu, B.; Salwen, C.; Kane, W.R. & Lemley, J.R.
Partner: UNT Libraries Government Documents Department

Implementation of tank volume measurement equipment at the Mayak Production Association

Description: One goal of the United States Russia Cooperative program to improve nuclear material protection, control, and accounting (MPC and A) in Russian facilities is to computerize material accounting techniques for bulk materials. Such materials include liquid solutions at radiochemical plants: dissolver, intermediate product, and waste. Material accounting techniques for tank volume measurements (TVM) are needed to determine the nuclear material content of these solutions (chemical and isotopic analysis are also required). The content is required to close the material balance in a radiochemical plant. Computerization of these techniques can provide unattended measurements of material flows, improved precision and accuracy, reduced operator effort, and lower radiation exposure of operators--with equipment that is predominantly remote from high radiation areas. This paper describes the technical activities that contributed to the successful integration of the TVM system, developed by Brookhaven National Laboratory (BNL), into the Mayak Production Association radiochemical plant conducted under the US/Russian cooperative MPC and A Program. US assistance with installation and adjustment of the instrumentation was completed in May 1997. After that, Mayak experts on measurement and metrology continued mastering and testing the equipment.
Date: December 31, 1997
Creator: Darenskikh, O.; Suda, S.C.; Valente, J.U.; Zuhoski, P.B. & Salwen, C.A.
Partner: UNT Libraries Government Documents Department