A position sensitive ionisation chamber for measurement of fission fragments and medium mass heavy ions

Abstract

A position sensitive ionisation chamber telescope is described with ΔE gas E gas sections which can measure simultaneously the specific energy loss ΔE, energy E and the position of heavy ion reaction products in the median plane. The position information is derived by having a split ΔE structure and by adopting the pulse division method for the signals collected by the two ΔE sections. For on-line angle calibration, the E-part of the anode structure is also split into five segments. The detector was tested with fission fragments from a 252Cf spontaneous fission source and with heavy ions from the pelletron tandem accelerator. Simultaneous measurement of ΔE and E gives good separation for heavy and light fission fragment groups. The position resolution is found to be 1.1 mm for fission fragments. The detector has been used in heavy ion reaction studies for measuring fission fragments, providing good separation from projectile-like particles.