Characterization of the transient response of diamond sensors to collimated, sub-ps, 1 GeV electron bunches

TL;DR

This study systematically characterizes the transient electrical response of diamond sensors to ultra-fast, high-energy electron bunches, revealing how ionization-induced charge dynamics influence sensor signals.

Contribution

It presents the first detailed modeling and experimental analysis of diamond sensor responses to sub-ps, 1 GeV electron bunches, advancing understanding of their transient behavior.

Findings

Transient modifications in sensor resistance observed

Model accurately predicts signal features

Charge carrier dynamics significantly affect response

Abstract

Diamond sensors (DS) are widely used as solid-state particle detectors, beam loss monitors, and dosimeters in high-radiation environments, e.g., particle colliders. We have calibrated our DS with steady $\beta$- and X-radiation, spanning a dose rate in the range 0.1-100 mGy/s. Here, we report the first systematic characterization of transient responses of DS to collimated, sub-picosecond, 1 GeV electron bunches. These bunches, possessing a charge ranging from tens to hundreds of pC and a size from tens of microns to millimeters, are suitably provided by the FERMI electron linac in Trieste, Italy. The high density of charge carriers generated by ionization in the diamond bulk causes a transient modification of electrical properties of DS (e.g., resistance), which in turn affects the signal shape. We have modeled a two-step numerical approach, simulating the effects on the signal of both the evolution of charge carrier density in the diamond bulk and the changes in the circuit parameters. This approach interprets features observed in our experimental results to a great extent.