A drift chamber with an intrinsic converter for measurement of γ-ray exit angles in electron and positron channeling

Abstract A drift chamber is described with an intrinsic converter for the measurement of γ -ray angles. Monte Carlo simulation and experimental data demonstrate that the accuracy of vertex reconstruction for e + e − pairs is approximately 70 μm. This corresponds to an angular resolution of the setup for the photon of approximately 4 × 10 −6 rad. The efficiency of vertex reconstruction has been investigated as a function of γ -ray energy and position. Experimental data are presented for measurements of the angular distribution of γ -rays for a 0.9 mm Al radiator and a 0.05 mm Si radiator.