A fast time-to-digital converter for position-sensitive radiation detectors with delay line readouts

Abstract

A fast time-to-digital converter (TDC) has been developed for use with position-sensitive radiation detectors having delay line readouts. The device is recommended for detector applications where high position resolution and low distortion are required at high rates. The device has 2 ns time resolution, less than 0.1% differential nonlinearity, and a recovery time of 70 ns. When used with a detector system having a delay line of temporal length τ, the following performance has been achieved: (1) a position digitization of 1 position resolution element per ns of delay line; (2) an average dead time of ( 3 4 τ+70) ns ; (3) a maximum incident radiation rate of ⋍ 4 τ ; and (4) a maximum conversion rate of ⋍ 1 (3τ) . Discriminator circuits reduce pile-up distortion to neglible levels for rates as high as those listed above. Finally, two converters may be connected together for synchronous operation as required by 2-dimensional ( x- y) detectors.