Agenda: Talk about Collector design for adapting 4.8 A, and gun for mechanical alignment and tolerences.

Collector: 

• Gunn presented simulation results of the collector for 4.8 A beam at 27keV, up to 5kV on collector, beam will reflect due to formation of virtual cathode at the collector entrance
  • Conclusion is that we will need more than 5kV (simulation worked for 6kV) to transport 4.8 A
  • This translated into 28.8 kW power deposited onto the collector, which is 4 times higher compared to minimum requirement of 2.4A @ 3kV (7.2kW) 
• Nominal (design of current collector) values are 2.5 A @ 3.5kV DC validated for 1 week at the ECTS
• Davide: we need bare minimum of 2.24 A on collector at 3.15 kV (27keV energy) with 14% duty cycle, which is what we are doing with today's e-cooler. 
• To be checked with EN-MME if the current collector can work at 5A x 6kV, and with SY-EPC what are the options in case we need to go to 6kV. To be noted that right now the limit is imposed by the collector powering which is 4A x 5kV (from LEIR).

Gun:

• More simulations needed for gun to check the effect of max tolerences (500um linear and 5milirad angular ?)
• Design will be 200um tolerances in alignment.

Magnet system:

• Check if we obtain from simulations of beam expansion an optimisation of the dimension of flange in front of expansion solenoid, or whether we need Al instead of the present one (SR235 or 1010 or other grade c < 0.17 %w.t.) to improve adiabaticity. Should we want to run at 600G the gun expansion solenoid, will we need Al? 
• Steering coils strength from operational cooler - Gerard has magnetic field detail (personal communication) that he can provide.
• 5 mm steering from gun arm to drift: sum of imperfections to give an estimate (Luke+Sameed) and see if enough.

(*) Note: the exp. solenoid yoke material is SR235 or 1010 or other grade c < 0.17 

Cathode:

• Gunn presented heating data of the cathode at the ECTS
• According to data sheet by supplier, we can extract 4.8 A current, but most likely have to increase the filament current
• The lifetime of teh cathode drops very quicly with increase in filament temperature, so one needs to also do test on the ECTS to see what will be lifetime if we operate at 4.8 A