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Extraction Scenarios of CIS. Zhengzheng Liu Mar 12th, IUCF. Pulse from linac. Extracted beam. Lambertson septum. Kicker 1. Shut down during extraction. Kicker2. Some Parameters in extraction. Extraction requirement estimation:
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Extraction Scenarios of CIS Zhengzheng Liu Mar 12th, IUCF
Pulse from linac Extracted beam Lambertson septum Kicker 1 Shut down during extraction Kicker2
Some Parameters in extraction • Extraction requirement estimation: • (1) 13 turns injection scheme (horizontal tune 1.72) • (2) 5 mm septum thickness • (3) 60 MeV injection and extraction energy • Total energy delivered to the target in pulsed mode: • Assuming linac current 0.5 A, inject 40ns electron beam per turn. with 13 turn accumulation, we obtain
Accumulated beam after injection • After multi-turn injection, we will carry out single-turn extraction. Below is the accumulated beam at the septum right after the last injection turn.
25mm 25mm Dxco= 47mm Electrostatic kicker for extraction The injection and extraction share the same section in the ring. Beam size is about 50 mm. So we need to bump the closed orbit by 47 mm in order to kick the whole beam into the septum. x’ 5mm x 8mm
Kicker field and aperture requirement • For extraction, kick angle is needed for 47mm closed orbit bump. Using electrostatic kicker: Thus we getE L=2.2 [MV/m] [m]for 60 MeV extraction. If assume 50mm kicker length, displacement within the kicker are: (1) at 13th injection turn. (2) at extraction (after 13th injection turn). Kicked beam θk beam Dxco
Aperture requirement for kicker 2 44mm horizontal aperture is enough for the 2nd kicker. 13th injection turn at the entrance of the second kicker. Dxco= 1.5mm. During extraction, kicker is shut down, so the phase space at the kicker location is like
Aperture requirement for kicker 1 After 12thinjection turn, we shut down kicker 2. Thus, the 13th injection turn phase space at the kicker 1 entrance requires –x aperture to be at least 26mm.
Vertical Lambertson extraction magnet The vertical Lambertson septum is used to extract beam vertically. Injection Extraction Septum 0.81m 1.15m 1.15m 0.2m
Septum strength and aperture x z • For 25 MeV extraction, . • For 60 MeV extraction, The beam displacement at the exit of septum is . So, due to the 50mm horizontal beam size, we need 50mm horizontal aperture and 1cm vertical aperture. Dz