The longest beam pulse remains at 5 milliseconds at 2 Amps, recirculation is 99.97 % (note that this is greater than the 99.92 % required for DC operation). The project remains in phase 2 configuration.
Currently pulse length is limited by a collector beam optics problem. Construction of the full collector power
supply was deferred until installation of the FEL introduced energy spread to the beam. A temporary 800 V supply was
installed capable of supplying 2 Amps current to one upper stage. The other stages were powered from taps on the gun
cathode supply which has only milliamp current capability.
[gif 12K] The collector beam optics as designed are shown here.
The optics with the 800 V temporary supply are shown here. It is now realized that an excessive number of
electrons are turning around and being captured at lower stages, exceeding their current capacity, and thus imposing
the 5 ms limit.
The new temporary collector power supply is capable of providing up to 3 KV at 2 Amps.
[gif 102K][jpeg 33K]