Development of high resolution GEM-based detector for the extracted electron beam facility at the VEPP-4M collider.
Budker Institute of Nuclear Physics has a special installation for generation of extracted beams of electrons and photons in a wide range of energies at the VEPP-4M collider. This facility requires high resolution low-mass coordinate detectors to precisely determine particles trajectories.
The specialized detectors with high spatial resolution and low material content were developed and during 2016 the first detector was manufactured (GEMs, flexible readout structures and electronics PCBs made at CERN Workshop, assembly finalized at the BINP).
The detector consists of three cascades of gaseous electron multiplier (GEM), the X-Y readout structure and detector electronics. Electronics is based on the APC128 ASIC (analog pipeline chip, 128 channels), six of these chips are used covering 768 channels in total. These channels are connected to the readout structure, which has two layers: 512 vertical strips and 256 horizontal strips, both directions have 0.25 mm pitch of the readout strips. Other key features are the following:
- sensitive area 128x64 mm with expected resolution better than 50 um,
- Altera Cyclone III FPGA with 40K logic elements and 1.16Mbit of internal RAM,
- 1GBit and separate 100MBit ethernet for data transfer and detector management,
- internal 4kV high voltage source.
The latest results obtained will be reported at the conference.