[en] A spectrometer for 14 MeV neutrons, to be used for fusion plasma diagnostics at JET, was developed. The spectrometer utilizes neutron scattering in a polyethylene foil with the detection of the scattered neutron and its associated recoil proton. For the detection of 12 MeV protons we have tested silicon surface barrier detectors, lithium-drifted silicon detectors and high purity germanium detectors. The lithium-drifted detectors were finally selected for use in the spectrometer. The lithium-drifted silicon diodes have also been used for direct spectrometry, utilizing the neutron induced charged particle reactions in silicon. The methods used for the energy calibration and the timing calibration of the diodes, both during the installation of the spectrometer and during operation, are described. The detection of 2 MeV neutrons is done by fast plastic scintillators. Since the neutron generator which was used to test the detectors supplies 14 MeV or 2.5 MeV neutrons only, a neutron energy converter has to be constructed to study the detectors at other neutron energies. In the actual spectrometer an array of scintillation neutron detectors is used. A method of calibrating such an array of detectors with a gamma source was elaborated and is also described here. The result of the calibration is a set of parameters than can be used to determine the high voltage settings and the discriminator levels that are needed to achieve homogeneous sensitivity for all the detectors of the array. The energy scale itself was then calibrated by using gamma sources of various energies. To test the spectrometer as a whole at a neutron generator, a test bed was constructed. A lithium-drifted silicon diode was used to measure the neutron flux and the neutron energy resolution in the test bed. (au)

[en] A lithium-drifted silicon detector has been used as spectrometer for fast neutrons, utilising the charged particle reactions in silicon. The neutron yield and neutron energy spread from a low voltage deuterium-tritium neutron generator has been measured. The results from the measurement confirm the calibration measurements done on a neutron spectrometer. (au)

[en] The report describes measurements performed for the energy calibration of the TANSY neutron detectors (two arrays of 16 detectors each one). The calibration procedure determines four calibration parameters for each detector. Results of the calibration measurements are given and test measurements are presented. A relation of the neutron detector calibration parameters to producer's data for the photomulipliers is analysed. Also the tests necessary during normal operation of the TANSY neutron spectrometer are elaborated (passive and active tests). A method how to quickly get the calibration parameters for a spare detector in an array of the neutron detectors is included

[en] A method to calibrate an array of scintillation neutron detectors, using a γ source, is presented. The count rate is measured as a function of high voltage at a given discrimination level. The obtained distribution is differentiated and a maximum value is determined which corresponds to the voltage at which the gamma peak passes through the discrimination level. By repeating the measurement at different discrimination levels the experimental dependence between the discrimination level and the high voltage is found as a straight line in a log-log diagram. Two calibration parameter for each detector are determined from a fit of these straight lines. A recalculation from the energy of the used γ source to any other energy is then possible and the obtained relation can be used to calculate discrimination levels and high voltages for each detector. Verification procedures are described. (authors)

[en] When using film for monitoring fast neutron, problems of fading have been reported. Early tests indicate that systematic errors in measurements of dose equivalents originate from this problem. Temperature and humidity might vary widely during transport and use. When the film is used in a personal badge, the possibility for higher temperature and humidity when worn close to the body has to be paid attention to. A study was performed with films shielded against humidity. These did show a better resistance to fading than parallell irradiated films open to humidity. Fading does occur, so exposure times must be kept to a few weeks, and evaluation times must be minimized. Films must be kept dry and air-tight whenever possible. (Aa)

[en] Our first task was to purchase a computer and to create a basic software library for the preliminary test of the components. Our choice was a Starburst system from CES. The computer was a PDP-11/70 on a chip. It is the same computer as the ones used by the auxiliary CAMAC crate controllers in the TANSY system. However, the host has a 256 kbyte memory instead of the 64 kbyte memory used in the crate controllers. The operation system is RSX11-M. It is a real time system with properties suitable for laboratory works. However, the computer works in 64 kbyte partitions which limits the size of the programs. Four program systems were written. The two first were one-parameter systems for amplitude and time measurements using the ADCs and TDCs which later should be included in the TANSY system. These systems were supplemented with two two-parameter systems, one for time and amplitude measurements and one for time measurements on 16 detectors simultaneously. The display capabilities of these program systems have been used extensively by the TANSY programs. The programs needed for the manipulation of the system give the user a possibility to manually run the system without any intervention from the normal CODAS control system. The programs have been used for calibration measurements as well as test of the TANSY system. The evaluation programs use the output file from a normal measurement. The data file may be tested for errors. The true events can be sorted into different configurations. The final one is the neutron energy sort program, which gives the neutron energy distribution

[en] The TANSY-KM5 neutron spectrometer is a system containing a lot of advanced electronic and mechanical components. The design of the system has been reported in two documents (CTH-RF--54 (INIS 17:10206) and CTH-RF--43 (INIS 14:797424)). The purpose of this documentation is to give a brief overview of the system as it is defined at the time of delivery

[en] This document describes procedures for the set-up and use of TANSY. It is a complement to the report 'Technical description of the Tansy Spectrometer, TANSY-KM5' (CTH-RF--81) and is aimed to guide the user through the initial adjustments and calibrations to a normal use of the instrument. Details, such as placing of jumpers and settings of potentiometers in electronic modules, are not given here. The calibration parameters obtained during the test period are listed at the end of each calibration chapter. They can be used as a first estimate of unknown parameters

[en] We present a method to calibrate an array of scintillation neutron detectors using a gamma source. The count rate is measured as a function of high voltage at a given discrimination level. The obtained distribution is differentiated and a maximum value is determined which corresponds to the voltage at which the gamma peak passes through the discrimination level. By repeating the measurement at different discrimination levels the experimental dependence between the discrimination level and the high voltage is found as a straight line in a log-log diagram. Two calibration parameters for each detector are determined from a fit of these straight lines. The obtained calibration parameters of the detectors give an absolute relation between the output fast pulse amplitude and the energy of radiation for any detector high voltage. Tests of the calibration method has been investigated and the two kinds of data correlate well. The calibration method have been performed. A relation between the neutron detector calibration parameters and producer's data for the photomultipliers has been used to get the detector settings for the TANSY neutron spectrometer. Test procedures for the spectrometer during its regular operation are proposed and a method is given to calibrate a future spare detector to be included in the array. (orig.)

[en] The main effort put into this work is the foundation of a reliable physical basis for a 12-16 MeV neutron-spectrometer at JET. The essential problem is the amount of scatterer that can be incorporated without losing resolution. We have found two possible methods, the use of a pure hydrogen scatterer and the use of a polyethylene foil scatterer. The pure hydrogen solution gives a very complicated spectrometer with large detectors. The polyethylene solution is limited by the thickness and the width of the foil. We judge the solution with the polyethylene foil to be the most promising one for a reliable spectrometer. However, a large foil area is needed. This gives a spectrometer design with an annular foil, an annular neutron detection system, and a central proton-detector. An efficiency of 10^-₆ counts/s per n/cm₂,s at the foil can be obtained with a resolution in the order of 100 keV for 14 MeV neutrons. Following the General Requirements given in the contract of this work, we concluded that an instrument with the desired properties can be made. The instruments is able to give useful information about the plasma from plasma temperatures of about 5 keV. (Authors)