Abstract:
Gas Electron Multipliers (GEMs) are a common amplification stage in gaseous detectors. A high electric field is created inside micro-patterned holes to produce charge amplification. When used in high-rate environments, such as AMBER, the charges produced inside the detector lead to non-negligible currents between the electrodes. This imposes more stringent requirements on the stability of the high-voltage supply, as the gain is highly sensitive to the applied potentials.
The commonly used Passive Voltage Divider (PVD), is a cascade of resistors to set the potentials and limit the currents. With this design, any significant current will inevitably cause a change of potential. In contrast, the newly developed Stabilized Voltage Divider (SVD) employs a common-drain circuit, that provides currents with minimal voltage drop. The SVD also provides active current limiters for all GEM electrodes, effectively mitigating continuous discharges.
The talk will cover the principle of the SVD and a comparison with the PVD in simulation and in a detector setup under strong irradiation.