Digital radiographic device, based on MWPC with improved spatial resolution

A digital radiographic device for medical diagnostics is described, with the spatial resolution improved by about a factor of 2 as compared to the previous modifications of this system operating in the hospitals of Moscow and Novosibirsk. The distribution of radiation intensity in the horizontal direction is measured with the help of MWPC, while in the vertical direction it is measured by a mechanical scanning. To avoid parallax, the chamber anode wires are not parallel, but “looking” at the source of X-rays. Each anode wire is connected to a separate electronic channel, which registers the X-ray quanta absorbed in the working volume of the chamber, with an energy exceeding 1–2 keV. To improve the spatial resolution of the chamber by a factor of 2 compared to the pitch of anode wires, the readout system registers separately the events with a hit at one anode wire and the events which contains two coincident hits at neighboring wires. The main characteristics of the device are the following: the number of channels of the MWPC is 640; the geometrical size of the channels is 0.6 mm; differential nonlinearity after performing corrections is not more than 1.5%. The dimensions of the digital image are 640 × 512.