Readout ASIC with SOI technology for X-ray CCDs

We developed an analog front-end application specific integrated circuit (ASIC) with a fully depleted (FD) silicon-on-insulator (SOI) technology for readout of X-ray CCDs. The ASIC contains seven readout channels, each of which is equipped with the correlated double sampling circuit followed by an amplitude-to-pulse width conversion circuit. We combined the ASIC with an X-ray CCD for performance evaluation tests. We succeeded in processing analog signals from the CCD and confirmed an X-ray imaging and photon-counting capabilities by irradiating a radioisotope ⁵⁵Fe. The energy resolution is 305 eV at 5.9 keV (full-width at half maximum) and the readout noise is 53.7 μV for power consumption of 33 mW per chip. The ASIC proves that the FD-SOI process can be a practically usable option for front-end applications.