PETsys Time-of-Flight Front module


Figure 2: PETsys TOFPET2 ASIC

The PETsys front-end module is the interface between the analog signals of the photo-sensor and the digital readout chain. It comes in two versions: (1) PETsys Front-End Module with 128 channels (Fig. 1) optimized for small systems with high channel data rate; (2) PETsys Front-End Module with 256 channels optimized for large systems with lower per channel cost. Both are made-up from three different boards : FEB/A_v2, FEB/S and FEB/I.

The FEB/A_v2 board has one TOFPET2 ASIC with 64 channels (Fig 2). The two versions of the Front-End Module use the same FEB/A v2 board as core component. The Front-End Module with 128 channels has two FEB/A_v2 boards and the 256 channels version has four boards. The FEB/A_v2 boards are mounted perpendicular to the SiPM arrays, and this geometry makes it easier to control and stabilise the temperature of the SiPM array. The board also has a temperature sensor near to the ASIC.

The FEB/S board is a purely passive board adapting the SiPM array to the input connector on FEB/A_v2 boards . This board will be different for different SiPM arrays models. The version of the board shown on figure 1 has two pairs of connectors that directly take the Hamamatsu S13361-3050AS-08 8x8 MPPC array, or the KETEK 8x8 array PA3325-WB-0808. Each FEB/S measures 53.1 x 25.4 mm and is four-side buttable such as to allow forming a continuously sensitive area with almost no dead space. The FEB/S also has two temperature sensors, each located in the middle of the pair of connectors taking one SiPM array. The Front-End Module with 256 channels has two FEB/S boards identical to the ones used in the 128 channel version.

The FEB/I, manages the communication between the FEB/A_v2 boards in the Front-End Module and the FEB/D_v2. The FEB/I provides the matching of data and configuration links to the FEB/D_v2. This board is different for the 128 and 256 channel versions of the Front-End Module. Up to eight PETsys Front-End Modules can be connected to one FEB/D board using a SAMTEC HQDC-030-xx.00-TTL-SBL-1N flat cable . It is also possible to plug the front‑end modules directly into the FEB/D_V2.


Figure 1: PETsys Front-End Module with 128 channels



Main Features

  • Based on the PETsys TOFPET2 ASIC.
  • Compatible with FEB/D_V2 board and DAQ board
  • Compatible with any analog SiPM photosensor or with Micro Channel Plate photosensors
  • Cost effective solution for reading several ten thousand channels
  • Comes in two versions: 128 channels and 256 channels
  • The 128 channels version allows a rate of 500 cps per ASIC channel
  • The 256 channels version allows a rate of 250 cps per ASIC channel
  • Provides bias voltage to the SiPM arrays
  • Power consumption per Channel: 6-8 mW