Upgraded Injector Test Facility - UITF What we started with… UITF as imagined

UITF – Issues and Concerns Modest shielding limits beam current to 100 nA CW. How to ensure we do not exceed maximum beam current? Finding a shielding solution for 100 uA operations CTF related: upgrade, CTF is oversubscribed (LCLSII), 80K shield line approach, “parking” the new ¼ CM Available klystrons, will we make 8 MeV? Very low current operation, how to see beam < 1nA ? MeV beam blows up when interacting with radiation baffles inside HDIce Resources are tight…UITF is a stretch goal 3 run periods per year, 3 weeks each. CIS to operate the facility. Is this realistic?

More concrete will be needed for 100 uA Try to keep 100uA inside Cave1 SCMB to consider PSS BCM(s) as Credited Control

CTF Related Kelly Dixon suggested a means to park the ¼ CM when not accelerating beam: circulate 80K LN2 through 35K shield line. UITF should not be a burden on CTF 34 wks per year Joe Preble and Ed Daly think this should be fine, although no thermal calculations have been done LN2 temp could fluctuate between 80 to 100 K (nitrogen supplied as liquid and gas), no problem for parking but what about for operations….? For Plan B, Cryo Group can add LN2 “water tower” inside CTF, which would provide steady LN2 source at constant temperature

Klystrons and Max UITF Beam Energy Curt, With 40uA beam current only, you can run at 8MV/m with less than 3kW from klystron. But you need a stub tuner to tune the FPC coupling Qext from the design value of 9e6 to 2e7. Haipeng Haipeng, So the take away is that with 40uA and a 5 kW klystron, we can expect the 7 cell cavity to operate at 8 MV/m. Assuming microphonic detuning is in the 15 Hz range. Curt Matt, For the new ¼ CM, we will get a 5 kW tube for the 7 cell cavity. For the two cell maybe one that does 3-4 kW which should be ok. Then expect 200 kV from the gun, the two cell gives 1-2 MV, add the 5.6 MV from 7-cell and voila, we are close to 8 MeV ... Curt

Low Current Operation Stripline BPMs see 7nA beam with 1 Hz integration time. But we want to see 1nA beam, or even less at UITF. Don’t want to fly blind

Recent test at Hall D: Trent Allison 3 nA 90 nA OFF

Need to work out details with HDIce and T. Allison, J. Musson Low Current Operation 𝟏𝒏𝑨=𝑫𝒖𝒕𝒚𝑭𝒂𝒄𝒕𝒐𝒓 𝑰𝒑𝒆𝒂𝒌+𝑰𝒃𝒂𝒔𝒆𝒍𝒊𝒏𝒆 𝟎.𝟏𝒎𝒔𝒆𝒄 𝟏𝟔.𝟕𝒎𝒔𝒆𝒄 x 10 nA = 0.06 nA ; Ibaseline = 0.94nA Ipeak Acceptable duration of high peak current: long enough to see but not long enough to depolarize Ibaseline Need to work out details with HDIce and T. Allison, J. Musson