BL1U at TRIUMFUCN Beamline

Kicker Magnet

(April 12, 2010)

UCN Facility in Meson Hall

12 mr 145 mr 18.5deflection:

KICKER

Kicker Specs:

500 MeV protons (p = 1090 MeV/c) 15 mr maximum deflection (Bdl = 0.0545 Tm); normal deflection 12mr effective length 1.5 m (physical available 2 m) aperture 100 mm x 100 mm (under review) field uniform to 5% over central 80 mm diameter region flat top 1 ms, flat to 5% over the 1 ms fires every 3 ms (330 Hz rep. rate, able to run continuously) can be re-configured (in <1 hr) to run as low as 100 Hz (33 Hz) rep rate power supply able to be located 10 m away

Notes:The aperture is an important constraint. Reducing the vertical aperture reduces the current needed for a given deflection (or reduces the length of the magnet). Decreasing the horizontal aperture decreases the inductance, and hence the voltage needed for ramp-up and ramp-down.

The rise time is also important. The high voltage needed for ramp up and down scales as 1/T rise

The trade-off between the different parameters is shown in the next two slides.

7 mm 60 mm

100 mm

“Two Sigma” beam spot containing 90% of beam is 16 mm wide by 5.5 mm high Beam moves ~8mm horizontally at exit of kicker when kicker fires Beam would still be 8.8 sigma from wall Smaller horizontal dimension reduces inductance and hence power supply voltage Smaller vertical dimension reduces the magnet length or the power supply current

It’s important not to make the aperture larger than necessary

Ceramic pipe

How small can the aperture be?

Proposed time division of beam

50sto

100 s

2/3 beam to SR

1/3 beam to UCN

normal TRIUMF beam, 4 min.

0

0

0

0

1 ms

2 ms2 ms

1 ms 1 ms 1 min.

120 A

120 A

120 A

Example of Proton Beam Sharing

0

0

120 A80 A

40 A

120 A

0 A 0 A

1 min. 4 min.

meson hall

UCN source

Preliminary Coil Design for UCN Kicker

Mike Barnes

Ferrite chamfer (11mm)

UCN Kicker

Mike Barnes

Aluminum

Ferrite

Air

Kicker Power Supply

Kicker Power Supply

Ramp-Up:

SW1 and SW2 are closed, magnet ramps up from the high voltage

+

-

Kicker Power Supply

End of Ramp-Up:

+

-

SW1 is opened. Current circulates through D3, D1, and SW2

Kicker Power Supply

Flat Top:

+

-

SW3 closes as required to maintain the flattop with the low voltage supply

+

-

Kicker Power Supply

Ramp-Down:

+

-

All switches open. Current is against the HV for fast ramp down.Stops at I=0 when diodes become back biased.

Kicker Aperture- Reducing Kicker Aperture sizes (Vert. & Horiz.) reduces the supply current & voltage requirements reduces P.S. costs- Limiting factor beam halo

Coil Lifecycle- Kicker repeatedly going ON/OFF Mechanical stresses?- Limit to the total number of cycles the coils can go thru?- Spares recommended (M.Barnes recommends incl. spare coils)- Extend the lifecycle by changing Kicker rep-rate & flat-top?

Kicker Failure Modes- Need to quantify the nature & frequency of kicker failure modes

Issues: