Source Test

The first silicon detector module ever with APV25 readout was assembled in early 2000 at HEPHY. It is made of two silicon detectors from 6" wafers, which are partially read out by three APV25S0 chips. The detector thickness is $320\,\rm\mu m$ with a strip pitch of $140\,\rm\mu m$. This ``Vienna APV25'' (V25) module is shown in fig. .

Figure: The Vienna APV25 silicon detector module.

A module test with a collimated $\rm ^{90}Sr$ source was performed in peak and deconvolution modes. In both cases, the signal is approximately Landau-distributed as shown in fig. .

Figure: Signal distribution of the V25 module with a source test in peak and deconvolution modes.

Unfortunately, one of the attached sensors showed current fluctuations at room temperature resulting in excess noise. In a beam test, this module was operated at $-10^{\circ}\,\rm C$, where the current was stable up to approximately twice the depletion voltage, and reasonable SNR numbers will be stated in that context (following section).