The electron injector for ASTRID is a 100 MeV Race-Track Microtron (RTM). This type of machine was chosen because it had proved itself at other installations to be a compact and economical machine, well suited for injection into an electron storage ring such as ASTRID. Our machine is to a large degree modelled on the one at use at MAXLAB in Lund, Sweden. The power for the klystron and electron gun acceleration voltage is delivered from the same pulse transformer, mounted in an oil tank below the klystron. The klystron is fed with about 100kV/100A, while the electron gun receives about 70kV. This power comes from a high-energy pulse supply by discharging a capacitor/inductor network. The 70kV electron pulse pulse enters the linac, where it receives a 5.3 MeV energy gain. The pulse then reverses direction via a small loop after the linac, and reenters the linac. Since this is a standing wave type, it can accelerate particles in both directions. After 17 additional passes through the linac, with increasing orbit diameter in the main dipoles, the beam is extracted and directed towards the storage ring septum. In this version of the LUND design, the beam can only be extracted at full energy. This is not a handicap, however, as the microtron is used primarily as an injector for ASTRID.

The main parameters of the microtron are summarized below: 

Last Modified 05 September 2021