A multimode digital detector readout for solid-state medicalimaging detectors

摘要

A multipurpose digital detector readout for medical imagingnapplications is presented. The readout is capable of measuring bothncurrent and charge, allowing a single detector array to perform imagingnfunctions previously accomplished with two separate machines. Thencircuit employs a variable rate ΣΔ analog-to-digitalnconverter (ADC) to measure current over a 130-dB dynamic range in a 1nkHz band and resolve charge pulses down to 360 e- at 100 000nevents/s. Detector currents of up to 7 ΜA and charge pulses as largenas 25 fC can be measured. A low-noise charge sensing amplifier (CSA) isncombined with digital pulse shaping to optimize the noise performancenand flexibility of the charge measurements. Fabricated in an 1.2 Μmncomplimentary metal-oxide-semiconductor (CMOS), the circuit occupies 1.5nmm2 and dissipates 11 mW/channel from a 5 V supply