  Position sensitive detectors based on gaseous scintillation proportional
counters with Anger-type readout are being used in several research areas such
as neutron detection, search for dark matter and neutrinoless double beta
decay. Design and optimization of such detectors are complex and time consuming
tasks. Simulations, while being a powerful tool, strongly depend on the light
transport models and demand accurate knowledge of many parameters, which are
often not available. Here we describe an alternative approach based on the
experimental evaluation of a detector using an isotropic point-like light
source with precisely controllable light emission properties, installed on a 3D
positioning system. The results obtained with the developed setup at validation
conditions, when the scattered light is strongly suppressed, show good
agreement with simulations.
