Enhancing Temporal Uniformity in Pulse-Dilation Framing Camera Using Curved-Dilation-Pulse

The pulse-dilation framing camera (PDFC) is a 2-D ultrafast diagnostic device with high temporal resolution (TR). In high-energy physics experiments, it can be used to investigate related transient processes and ultrafast dynamics. Nevertheless, the transmission of linear dilation pulse (DP) along the photocathode (PC) may lead to TR non-uniformity in the PDFC, causing variations in the physical information captured at different time points and potentially resulting in distorted observations. To address this issue, a curved DP (CDP) was designed using an insulated gate bipolar transistor (IGBT), transformer coils, and high-pass filters, and its application in improving temporal uniformity (TU) was investigated. The research findings indicate that the IGBT circuit can generate a CDP with non-linearly rising amplitude and a slope ranging from 0.132 to 3.39 V/ps. Under conditions of -3-kV PC voltage, an initial time width of 10 ps for the electron beam (EB), and a drift distance of 500 mm, when applied to an 80-mm long PC, the average relative error (ARE) of EB dilation ratio (EBDR) along PC can be minimized to 0.63% (EBDR: $11.68\times $ – $11.81\times $ ). This represents a significant enhancement in TU compared to the 7.20% ( $3.84\times $ – $4.42\times $ ) achieved with the linear ones. Furthermore, when evaluated based on the maximum relative error of EBDR along PC, the CDP achieves 1.11% compared with the multi-group high-precision time synchronization requirements of multi-pulse fusion (MPF, 9.14%, $9.52\times $ – $10.39\times $ ) and V-shaped pulse superposition (VSPS, 26.15%, $11.28\times $ – $14.23\times $ ), the CDP based on IGBT technology only requires a single group of time synchronization to effectively enhance TU. Meanwhile, the CDP can also be applied to a 1-D streak camera for mitigating dynamic spatio-temporal distortion.