Cryogenic detector modules and edgeless silicon sensors

We are studying the operation of silicon microstrip detector with readout electronics in the temperature range from 90 to 130 K. The sensor can be operated in the current-injection mode which significantly improves its radiation hardness. A first module prototype has been built, with APV25 readout chips and an embedded microtube, providing efficient low-mass cooling of the whole module with a two-phase flow of N 2 or Ar. First pedestal and pulse shape temperature dependencies are presented for this module. We have also built an edgeless test module with two pairs of laser cut sensors, with both angular and parallel cuts with respect to the strips (at 120 μ m pitch). We are studying the efficiency of the microstrip sensors very close ( < 200 μ m ) to the physical border of the cut silicon crystal and present here some electrical characteristics.