Prompt Kicker M. Aoki

2

3 H-Line Kicker Prompt Burst: 5e8 / H-line exit – Any detectors will be saturated. Need to reduce the prompt burst by kicker. Mag. Field> 385 Gauss Gap320 mm Width320 mm Length400 mm No.4 Fall Time< 300 nsec Rep. Rate25Hz Electric NoiseMinimum

Kicker Performance H-line long Long H-line version -HK1-HK2-SEP-HS3-HK3-HK4-HS4-HS5- No slits (only mag. aperture) Suppression Factor 3:81199 by G4BL < 1/10000 (~50k/pulse) Kicker OFF Kicker ON

Kicker Performance (Short H) HS12-SEP-HS3-HS34-HB2 – HB2 exit: 370k/pulse – Suppression is not high. HS1234-HS3-SEP-HB2 – HB2 exit <26k/pulse (MC stat. limited) – Good suppression. – Can we reduce the number of kicker magnets?

No. of Kicker Magnets onHK4 off HK34 offAll off No mm mm mm mm H-line HS3 entry Black: hk1-4 off Purple: hk1-2 on Red: hk1-3 WC1 Four kicker-mag system: best Three kicker-mag system -10% of acceptance Prompt suppression: OK Two kicker-mag system -50% of acceptance Prompt suppression: 100 times worse exit may improve the suppression.

1 st Design No-flat part: OK 435 Gauss / 10kA B y L = 1.3 T*cm Long fringing field By N. Matsumoto 1-turn coil: L = 600 nH

Magnet Impedance matching elements Internal inductance INTERNAL INDUCTANCE FALL 500 A 100 nH307 nsec 300 nH361 nsec 500 nH430 nsec 500 A 10 kA FALL TIME MAGNET COIL CURRENT [A] 1) MAGNET INDUCTANCE: 600 nH 2) IMOEDABCE MATICHING ELEMENT: 8000 pH, 100 Ohm 3) MAGNET COIL CURRENT: 10 kA 4) PFL IMPEDANCE: 5 Ohm MAY. 06, 2011

9 Transmission Efficiency Internal Inductance = 100 nH Magenta: kicker current Green: mu-e signal birth Blue: mu-e detector Internal Inductance = 500 nH -10% --- not so bad.

2 nd Design Consider the coupling with the adjacent mag. Combine two magnets.

Magnet Spec. １． B ３８５ Ｇ ａｕｓｓ ２． Gap ３２０ ｍｍ ３． Width ３２０ ｍｍ ４． Length ４００ ｍｍ x ２ 4.1BL > G.cm ５． Fall time < ３００ ｎ ｓｅｃ ６． Coil ６．１ No. of turns １ Ｔ ６．２ Current １０，３ ００ Ａ （１ / ４ crosssection:cm ） Calculate ¼ model by TOSCA 622 nH per coil Bmax = 390G BL = 40,695 Ｇ・ cm -> current can be reduced by 20%

10kA driven by modulator 1 10kA driven by modulator 2 aluminum alloy ferrite 1. CONFIGURATION OF MAGNET 1) Each magnet consist of two symmetrical shape ferrite cores as shown in above figure. 2) Each one turn coil excite for two magnets are set in series. 3) Each coil is excited by own modulator power supply. 2. MODULATOR SPECIFICATION 1) Charging voltage of PFL: 50-kV 2) PFL (COAXAIL CABLE) impedance: 5-ohms 3) Pulse width: 2.0 ~ 2.5 micro-sec 4) Load: short terminated inductor (622-nH) 3. DISCUSSIONS We would like to discuss how to reduce the unwanted residual inductances, which mainly caused by wiring between PFL (and or PF) and thyratron tube, and wiring the magnet coils can be seen in page 2-3.

rise time: 0 to 100% wiring inductance in vacuum expanded view of falling time:

Summary “HS2 - HK1-4 - HS3” works for H-line short. Need HS3 entry and HS2 exit. Better to have 4-magnets kicker system. But 2-magnets kicker system is acceptable in order to start the physics run. Basic design by KEK exists (ver. 2) – Two-magnets two-power system: 2.2 Oku-yen/full – Internal inductance is the issue. – Nippon Koshuha is examining the details of this design by using US-Japan Alternative design by BNL is ongoing by using US-Japan – A report by the middle of Feb. including cost estimate.