A position-sensitive twin ionization chamber for fission fragment and prompt neutron correlation experiments

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 830; pp. 366 - 374
• Main Authors: Göök, A., Geerts, W., Hambsch, F.-J., Oberstedt, S., Vidali, M., Zeynalov, Sh
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 11.09.2016
• Subjects: Anodes; Charge division readout; Conservation of mass; Electrodes; Energy resolutions; Fission fragment; Fission fragments; Fission neutrons; Fission reactions; Ionization; Ionization chamber; Ionization chambers; Kinetic energy; Kinetics; Optical sensors; Position sensitivity; Position-sensitive detectors; Prompt fission neutrons; Proof of principles; Position-sensitive detectors; Fission fragments; Ionization chamber; Prompt fission neutrons; Charge division readout
• ISSN: 0168-9002; 1872-9576; 1872-9576
• DOI: 10.1016/j.nima.2016.06.002

A twin position-sensitive Frisch grid ionization chamber, intended as a fission fragment detector in experiments to study prompt fission neutron correlations with fission fragment properties, is presented. Fission fragment mass and energies are determined by means of the double kinetic energy technique, based on conservation of mass and linear momentum. The position sensitivity is achieved by replacing each anode plate in the standard twin ionization chamber by a wire plane and a strip anode, both readout by means of resistive charge division. This provides information about the fission axis orientation, which is necessary to reconstruct the neutron emission process in the fully accelerated fragment rest-frame. The energy resolution compared to the standard twin ionization chamber is found not to be affected by the modification. The angular resolution of the detector relative to an arbitrarily oriented axis is better than 7° FWHM. Results on prompt fission neutron angular distributions in 235U(n,f) obtained with the detector in combination with an array of neutron scintillation detectors is presented as a proof of principle.