Publications
Publication Information
| Title | Improving the Operational Lifetime of the CEBAF Photo-Gun by Anode Biasing | ||
| Authors | Joshua Yoskowitz, Joseph Grames, Geoffrey Krafft, John Hansknecht, Carlos Hernandez-Garcia, Bernard Poelker, Gabriel Palacios-Serrano, Marcy Stutzman, Riad Suleiman, Sebastiaan Van der Geer, W. Sajini Wijethunga | ||
| JLAB number | JLAB-ACC-21-3485 | ||
| LANL number | (None) | ||
| Other number | DOE/OR/23177-5339 | ||
| Document Type(s) | (Meeting) | ||
| Category: | Electron/Positron Sources |
||
| Associated with EIC: | No | ||
| Supported by Jefferson Lab LDRD Funding: | No | ||
| Funding Source: | Nuclear Physics (NP) | ||
|
Meeting Paper compiled for IPAC21 Proceedings Proceedings of IPAC 2021 Edited By Liu Lin, John M. Byrd, Regis Neuenschwander, Renan Picoreti, Volker R. W. Schaa JACOW (2021) Page(s) 2840-2842 | |||
| Publication Abstract: | The operating lifetime of GaAs-based photocathodes in DC high voltage electron photo-guns is dominated by the ionization rate of residual beamline gas molecules. Ions created within the photo-gun potential are accelerated toward the photocathode, leading to a reduction of the photocathode quantum efficiency (QE). In this work, experiments were performed to quantify the improvement in photocathode charge lifetime by biasing the photo-gun anode with a positive voltage, which repels ions generated downstream of the anode. The method was tested by successively applying and removing the anode bias voltage of the CEBAF photo-gun at the Thomas Jefferson National Accelerator Facility over many months of beam production. The photocathode charge lifetime improved by almost a factor of two when the anode was biased compared to the usual grounded configuration. Simulations were performed using the particle tracking code General Particle Tracer (GPT) with a new custom element and electric field models of the CEBAF photo-gun made using CST Microwave Studio software to explain the improvement. The experiment results and conclusions supported by the GPT simulations will be presented. | ||
| Experiment Numbers: | |||
| Group: | Ctr for Injectors&Sources | ||
| Document: | |||
| DOI: | https://doi.org/10.18429/JACoW-IPAC2021-WEPAB104 | ||
| Accepted Manuscript: | wepab104.pdf | ||
| Supporting Documents: | |||
|
|||
| Supporting Datasets: | |||