PETsys Front-End Module
Core component of the PETsys SiPM readout system
The PETsys Front-End Module (FEM) is the interface between analog photosensors—such as SiPM arrays or micro-channel plate photodetectors—and the digital PETsys readout chain. After the front-end stage, only digital signals are used. While PETsys can develop custom FEM designs to meet unique detector configurations and specific application requirements, we offer two standard solutions that can cover a wide range of applications: FEM128 and FEM256.
The FEM128 is a 128-channel front-end module optimized for applications requiring high per-channel data rates. It is built from three boards: FEB/A_V2 (analog front-end), FEB/S (sensor adapter), and FEB/I (interface/control). FEM128 integrates two FEB/A_V2 boards, each hosting a TOFPET2 ASIC with 64 channels, mounted perpendicular to the SiPM arrays to facilitate temperature control.
The FEB/S board adapts specific SiPM arrays and is tileable on all four sides, enabling large continuous detector surfaces with minimal dead space. Temperature sensors are included near both the ASICs and the SiPM arrays to support accurate thermal monitoring and long-term operational stability under varying environmental and operating conditions. The FEM128 supports event rates up to approximately 500 kcps per channel, with a total power consumption of about 14.2 mW per channel. Up to eight FEM128 modules can be connected to a single FEB/D-1K and up to 16 FEM128 modules to a single FEB/D-8K, providing a scalable and flexible solution for medium-to large-size detector systems.
The FEM256, housing 4 TOFPET 2 ASICs, targets large-scale systems prioritizing compactness, simplified cooling, and lower cost per channel. It integrates the functions of FEB/A and FEB/I into a single 256-channel board measuring 50 × 50 mm². FEM256 supports rates up to 300 kcps per channel, with similar power consumption (~14 mW/channel). It is designed for optimal thermal integration using an aluminum cooling bar placed between the FEM256 and a dedicated FEB/S-256 sensor board. Up to 16 FEM256 modules can be connected to a FEB/D-8K.
PETsys can customize the FEB/S boards of both FEM128 and FEM256 to match specific SiPM array models, sizes, and geometries, ensuring compatibility with your detector architecture.
FEM128
FEM256
FEM256 board: hosting 4 TOFPET2 ASICs
Main Features
- Based on PETsys TOFPET2 ASIC and compatible with PETsys FEB/D and DAQ-PCiE boards for seamless system integration.
- Compatible with any analog SiPM photosensor or Micro Channel Plate photosensors for flexible detector applications
- Cost-effective solution for reading several tens of thousands of channels in large-scale systems
- Available in two versions: FEM128 with 128 channels and FEM256 with 256 channels
- The 128-channel version supports up to 500 kcps per ASIC channel
- The 256-channel version supports up to 150 kcps per ASIC channel
- Provides bias voltage directly to the SiPM arrays, simplifying system design and external power requirements
- Low power consumption of only 14 mW per channel