An updated history of the thyratron lifetimes at the Stanford Linear Accelerator Center

The Stanford Linear Accelerator Center (SLAC) has been in almost continuous operation since the middle 1960s, providing a remarkable opportunity to amass high power thyratron lifetime and reliability data. This paper continues the review of the history of the Linac thyratron usage, with the primary focus during the Stanford Linear Collider (SLC) era, specifically, the last four years of accelerator operation. The 24 hour a day, extended operation of the 243 modulator Linac, provides a significant amount of data. Nominal SLC operational parameters for the Linac thyratrons are: 46 kV anode voltage (Epy), 6.3 kA peak current, 5.4 us esp, with a repetition rate of 120 pps. The Linac does support other on-going experiments, usually at a lower repetition rate. Within these constraints of operation, this paper explores the historical thyratron lifetimes and some of the common failure modes found at SLAC. With this information, an estimate can be made as to how long these thyratrons can be expected to operate in the Linac before failure. This information is also being used to validate reliability modeling for the Next Linear Collider (NLC). The goal is to support high power thyratron development for the NLC, to have a commercially available product, that will operate with a 50,000 hour Mean Time Before Failure.