Double-sided Silicon Strip Detector for the study of Double Hypernuclei II

The DSSD has an effective area of $64$ mm $\times$ $32$ mm, the thickness of 300 $\mu \textrm{m}$ and 50 $\mu \textrm{m}$ strip pitch. A number of strip-readout are 1280 channels in p-side and 640 channels in n-side, which correspond to 10 and 5 VA chips installed on the DSSD. We use a V550 C-RAMS (CAEN Readout for Analog Multiplexed Signals) ADC module as an ADC and a V551B C-RAMS module as a controller. In order to evaluate the performance of the DSSD in terms of the S/N ratio, we measured the pluse height distribution of $\beta$-ray passing the DSSD from a ${}^{90}$Sr source. We took about $100,000$ events data at variouse bias voltages, in order to check the depletion depth. At the bias voltage of $\pm 40$ V, we have obtained the S/N ratio as 33.76 $\pm$ 0.14 at p-side and 22.49 $\pm$ 0.09 at n-side for the minimum ionizing particles. The present results show the DSSD has sufficient S/N ratio to detect both $\Xi^{-}$ and $K^{+}$.