1. JLEIC ion fullsize booster (2256m) space charge limit (Δν=0
JLEIC ion fullsize booster (2256m) space charge limit (Δν=0.15) for p/D+/Pb at various injection energy
Linac Ek (MeV/u)
Booster 1 ext rigidity (Tm)
Booster 1 ext Ek (GeV/u)
Fullsize booster peak current (A) at space charge limit (=avg current if no gap) p D+
Pb67+
Pb82+
150 85 40 20
5.13 (p=6GeV/c)
2.2
1.2
0.78**/0.83*
0.32
0.12
22.93 6
2.63
1.47
0.78**/1.10*
0.42
0.16
26.29 7
3.11
1.77
0.78**/1.45*
0.54
0.20
29.65 8
3.6
2.08
0.78**/1.85*
0.69
0.26
200
110 57
1.1**/1.29*
0.48
0.19
250
140 75
1.48**/1.9*
0.71
0.28
1.48**/2.4*
0.9
0.35
285
160
1.75**/2.6*
0.96
0.38
Assumes:
Gaussian bunch with 6σt=40mm at booster 1 injection (normalized emittance will be larger with higher injection energy); normalized emittance constant after booster 1 injection; 6σz=bucket length when injected into the fullsize booster
Pb strip at 13MeV
**: each booster 1 cycle fills at least 1/56 of the fullsize booster circumference, limited by booster 1 space charge, assuming Gaussian bunch, 6σz=circumference when captured in booster 1
*: booster 1 cycle doesn’t have a lower limit of how much charge to be filled

2. Possible optimization for ion bunch formation and transient beam loading
Capable to inject proton with ~0.75A average current and two head/tail long bunches (40m bucket each) of ~1.5A peak to compensate transient
Assuming 60MV ion ring RF voltage, RF power required for this case is ~4.8MW (200kW/cavity, 24 two-cell cavities, in 6 or 4 CMs)
The larger long bunches should be injected the last
Operate D+ and Pb at ~0.3A beam current and 60MV RF with half detuning and full transient correction using 4.8MW power.
250MeV linac and 7 GeV Ek booster 1 should be adequate, increase to 8 GeV would give a better margin
Or lower to 1A peak/0.5A avg with 200MeV linac
RF voltage/wattage can be reduced further if bunch length is relaxed.
30MV, 12 cavities (3 CMs) for phase 1?

3. Forming the proton bunch train (option 1)
Accumulate in booster 1 at MeV (p) in coasting beam, with possible DC cooling keeping the emittance
Capture to h=1 RF bucket, accelerate to booster 1 top energy 8 GeV (p)
Compress to bunch length ~13.4m rms, 6σz=80m, split into two bunches of σz=6.7m in two 40m buckets
Extract from booster 1, inject into fullsize booster in two ~40m buckets, ramp back booster 1 to injection. Kicker rise time ~40ns
Repeat 1-4 for 26 cycles (fills buckets 3-54 out of 56 in the fullsize booster)
DC cool the 52 bunches
Reduce DC cooling beam current.
Repeat 1-2, compress into σz=6.7m bunches. Transfer the bunch into fullsize booster to fill bucket #2
Repeat 6 to fill fullsize booster bucket #55
Ramp fullsize booster to bunch splitting energy
Perform factor of 64 bunch splitting in the fullsize booster (6 binary splits)
Transfer from fullsize booster into collider ring.
Compress the bunches in 476MHz RF system. Capture in the 952.6MHz RF system
BB cooler
1 gap, 80m
Each green dot represents two bunches, each in a 40m bucket
0.75A
Each blue dot represents one double charged bunch in 40m bucket

4. Forming the proton bunch train (option 2)
Accumulate in booster 1 at MeV (p) in coasting beam, with possible DC cooling keeping the emittance
Capture to h=1 RF bucket, accelerate to booster 1 top energy 8 GeV (p)
Compress to bunch length ~13.4m rms, 6σz=80m, split into two bunches of σz=6.7m in two 40m buckets
Extract from booster 1, inject into fullsize booster in two ~40m buckets, ramp back booster 1 to injection. Kicker rise time ~40ns, flat top ~230ns
Repeat 1-4 for 26 cycles (fills buckets 3-54 out of 56 in the fullsize booster)
DC cool the 52 bunches. splitting in the fullsize booster (6 binary splits). Compress the bunches in 476MHz RF system. Transfer from fullsize booster into collider ring and capture in 952.6MHz system in odd numbered buckets # kicker rise time ~300ns, flat top up to 7μs
Repeat 1-2, compress the bunch into σz=6.7m bunches. Transfer the bunch into fullsize booster
Ramp fullsize booster to bunch splitting energy, perform factor of 64 bunch splitting. Compress the bunches in 476MHz RF system. Adjust the booster timing and transfer the bunch train into the collider, capture in even numbered 952.6MHz buckets # Transfer kicker rise/fall time ~20ns, flat top ~134ns.
An alternative is to perform factor of 128 split and transfer to fill all buckets #
Repeat 7-8 and transfer another bunch train to even numbered 952.6MHz buckets #
Regular bunch in even buckets
20ns for kicker rise
227ns abort gap