Speaker
Description
Timepix is a hybrid pixel detector used to measure mixed radiation fields. Several Timepix-based instruments are currently used on the International Space Station, as part of the Artemis program on the Orion Spacecraft, the Gateway lunar space station, and the Lunar Human Landing System, and on various scientific missions such as Polaris Dawn. New space-based instruments are being developed with Timepix2. Timepix2 allows measurements of particles in energy mode—Time over Threshold (ToT) mode—with ToT signal length being proportional to energy. However, energy measurements in Timepix2 have a limitation due to a pixel saturation effect that occurs beyond the upper end of the Timepix2 dynamic range (>3.4 MeV).
We present a parallel signal processing route for signals from high energy depositions that avoids saturation in measurement. When energy is deposited in the Timepix2 sensor, the resulting pulse is processed in the ASIC. This pulse also appears on the bias of the detector, allowing for a potential additional measurement of the same energy deposition. We developed the capability to measure this pulse on the bias, the backside pulse, and route this simultaneous measurement data back into the data stream. We constructed a circuit that takes pulses off the bias and converts them to a ToT signal. Timepix2 has a set of digital pixels that can receive external information, which we implement to receive the ToT signal and send the backside pulse data to be processed in the Timepix2 chip. To our knowledge, we are the first to test and use this digital pixel capability. We present beamline tests of the backside pulse processing and digital pixel system and discuss system linearity with energy, applicable energy ranges, and applications of this system to space dosimetry and radiation measurement.
| Workshop topics | Detector systems |
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