Pixel Detectors

The work reported in this section has been performed by members of RD8 and RD19.

GaAs pixel detectors have been developed which are compatible with the RD19 Omega3/LHC1 [13] read-out electronics. The pixel detectors form an array of 16 x 128 elements each 50$\mu$m by 500$\mu$m in size. The latest pixel detectors fabricated by Alenia with an ion-implanted ohmic back contact have been tested in a 120GeV/c pion beam. The detectors were 200$\mu$m thick and biased to 500V. The detection efficiency dependence upon the Omega3 comparator threshold for the two planes of GaAs pixels under test in an Omega2 silicon telescope is shown in figure 3. The pixels performed as well as the silicon telescope and demonstrated 100% CCE. These results are from on-line analysis but show that GaAs pixels work extremely well.

  

Figure 3: Detection efficiency of GaAs pixel detector AL-IOC-10 with an ion-implanted ohmic contact as a function of Omega3 read-out chip comparator threshold value