Design of Active-Type Personal Dosemeter for High-Energy Neutrons
*In order to design an active-type personal dosemeter having sufficient sensitivity to high-energy neutrons up to 100 MeV, the characteristic response of several types of silicon (Si) semiconductor detectors has been investigated experimentally and theoretically. At first, the response of each detector has been checked to protons accelerated by a Van de Graff accelerator installed at Kobe University. A fully-depleted Si detector was selected as a promising detector element owing to a simple structure and comprehensive characteristics. In the next step, neutron irradiation experiments were carried out in a monoenergetic reference field in JAEA. On the other hand, theoretical distributions of the deposited energy were estimated in a simplified geometry consisting of Si and PE layers. An agreement in the relative shape was confirmed between the theoretical and experimental results. Applying this calculation procedure to other neutron energies and various thickness of sensitive layer, it was found that the energy dependence could be improved by the two-window technique by setting different discrimination levels on the pulse height. Another important characteristic of the angular dependence was also discussed for practical application of a personal dosemeter for high energy neutrons.
Electronic personal neutron dosemeters for energies up to 100 MeV: Calculations using the PHITS code
Abstract Measurements and calculations of pulse height spectra induced by normally incident neutrons with energies between 144 keV and 100 MeV in silicon have been performed with the PTB prototype personal neutron dosemeters DOS-2002 and DOS-2005, based on silicon detectors with effective thicknesses of 40 and 5.6 μ m , respectively. This work describes calculations using the PHITS code and compares measured and calculated pulse height spectra and personal dose equivalent responses. Measurements and calculations agree on an absolute scale by a factor better than 2. The personal dose equivalent response of the prototype personal neutron dosemeter DOS-2005 is much flatter than that of the DOS-2002 in the neutron energy range investigated.
A slowly rotating coil system for AC field measurements of Fermilab Booster correctors
A method for measurement of rapidly changing magnetic fields has been developed and applied to the testing of new room temperature corrector packages designed for the Fermilab Booster Synchrotron. The method is based on fast digitization of a slowly rotating tangential coil probe, with analysis combining the measured coil voltages across a set of successive magnet current cycles. This paper presents results on the field quality measured for the normal and skew dipole, quadrupole, and sextupole elements in several of these corrector packages.