High Rate Kicker Preliminary Study (Quick Update) Tony Beukers/Tao Tang 4/8/14.

High Rate Kicker Preliminary Study (Quick Update)

Tony Beukers/Tao Tang

4/8/14

2

Parameters for Spreader

Parameter Value Unit

Energy 4 GeV

Kick 1 mRad

Rate 1 MHz

Length 6 ? m

Aperture 1 cm

Pulse to pulse stability 100 ppm

Jitter When Off (compared to main pulse)

50 ppm

• “Jitter When Off” from “Post Laser Heater Diagnostic Beam-Line PRD”

• Works out to integrated field of 13.4mT-m required

• For all topologies considered, 5mT most reasonable 3ea. 1-meter sections

• Bi-polar pulse possible with two separate kickers, so not an area of extreme focus.

3

Magnet Cross Section

II

• 2-types of magnets shown to the right. C-core and Window frame. Best choice depends a bit on driver topology.

• Ferrite loaded magnet. Losses from drive field highly dependent on the core type. For 5mT, 100ns sine wave excitation at 1MHz 11W/m for 4M2, 450W/m CMD5005 (common kicker material).

• On the order of 2% change in effective µ over duration of pulse.

• Coated beam-pipe used to shield beam current from magnetic coupling to ferrite.

4

Beam Coating Losses

Figure from [2]

• Losses in conductive coating increase with beam current, high frequency components of pulse, and pulse rate.

• Eddy currents from the driver pulse go down with increased coating resistivity. . .but loss from the beam image current goes up.

• Beam image current losses (length =8.3µm, q=0.5nC):

∫ 𝑖2𝑑𝑡= 𝑞2

2√𝜋 𝜎𝑡

𝑃= 𝐼𝑅𝑀𝑆2 𝑅=𝑅× 𝑃𝑢𝑙𝑠𝑒𝑅𝑎𝑡𝑒×∫ 𝑖2𝑑𝑡

• Eddy current losses found through simulation.

• Total loss is 600W/m with 90Ω/m coating.

• Reduce loss (if necessary) with conductive strips,

5

In-Tunnel Driver

• Mount MOSFET drivers

directly on Ferrite loaded

magnets in tunnel.

• Multiple drivers reduces the

inductance of each section

so each driver can rise in

tens of ns.

• Easily redundant for longer

system lifetime.

• 5mT/m achievable goal.

Figures from LBNL NGLS paper. [2]

6

Driver Types

5 Segments/meterMOSFET Losses 520W/m

9 Segments/meterMOSFET Losses 1000W/mResistive Losses 3285W/m



*Losses assume NON rad-hard MOSFET

7

Driver Types





*Losses assume NON rad-hard MOSFET

Too much power!

8

Tunnel Radiation

• Total ionizing dose causing non-recoverable failure in MOSFET is main problem.

Back-of-envelope yields ~15kRad/year.

• 1 rad-hard device rated at 100kRad (6 years). Expensive, not electrically great,

hard to get.

• Collimator reduces radiation by a factor of 10-100.

• Like to put NON rad-hard device in total dose test. Could it survive behind a

collimator?

• More input and/or modeling from RP may be useful.

Volume of electronics: d3

R

Length contributing Radiation: Lrc

𝑃=𝑊𝑎𝑡𝑡𝑠𝑚

×𝐿𝑟𝑐×𝑑2

2𝜋 𝑅×𝑋 0

9

Transmission Line Kicker

T-Line

Magnet LoadII

I+

I- Ferrite

• Loaded sections of ferrite and discrete capacitors simulate a transmission line.

• Used at SLAC in damping ring and at CERN.

• Typically used in high voltage. But for our low voltage, possible to tune magnet impedance with small chip capacitors.

10

Transmission Line Ringing

• Ringing damps to below 50ppm of the main pulse

within 1µs. Ringing reduced with more sections.

L 1

{L c }

1 2L 2

{L c }

1 2L 3

{L c }

1 2L 4

{L c }

1 2L 5

{L c }

1 2L 6

{L c }

1 2L 7

{L c }

1 2L 8

{L c }

1 2L 9

{L c }

1 2L 1 0

{L c }

1 2

C 1{C c }1

2

C 2{C c }1

2

C 3{C c }1

2

C 4{C c }1

2

C 5{C c }1

2

C 6{C c }1

2

C 7{C c }1

2

C 8{C c }1

2

C 9{C c }1

2

C 1 0{C c }1

2

V 1 TD = 3 0 n

TF = 3 0 nP W = 7 0 nP E R = 1

V 1 = 0

TR = 3 0 n

V 2 = 5 0 0

A C = 1

PARAMETERS:L c = {1 1 1 1 . 6 6 6 6 7 n / n u m }

C c = {7 1 1 4 . 6 6 6 6 7 p F / n u m }

R l = {S q rt (L c / C c )}

n u m = 2 0

V 1 V 3V 2 V 4 V 7 V 9V 6 V 8

R 1{R l}

0

V 1 0V 5V 0

L 1 1

{L c }

1 2L 1 2

{L c }

1 2L 1 3

{L c }

1 2L 1 4

{L c }

1 2L 1 5

{L c }

1 2L 1 6

{L c }

1 2L 1 7

{L c }

1 2L 1 8

{L c }

1 2L 1 9

{L c }

1 2L 2 0

{L c }

1 2

C 1 1{C c }1

2

C 1 2{C c }1

2

C 1 3{C c }1

2

C 1 4{C c }1

2

C 1 5{C c }1

2

C 1 6{C c }1

2

C 1 7{C c }1

2

C 1 8{C c }1

2

C 1 9{C c }1

2

C 2 0{C c }1

2V 1 1 V 1 2 V 1 3 V 1 4 V 1 7 V 1 9V 1 5 V 1 8V 1 6 V 2 0

VV

V

Sum of all magnet currents.

Traveling Waves

11

Conclusions

• “In Tunnel” and “Transmission Line” Kicker both still options.

• “In Tunnel” Kicker does not have a perfect driver solution, but

three topologies are possible. Need testing and more RP

input to fully evaluate radiation effects.

• “Transmission Line Kicker” looks promising according to

simulations. Some testing on the spare NDR magnet would

be useful.

• Bottom line: Both methods look feasible. Additional testing to

determine which is best.

12

References

[1] M.J. Barnes, L. Ducimetiere, T. Fowler, V. Senaj, L. Sermeus. “Injection and extraction

magnets: Kicker magnets” Mar 2011. 26 pp. Published in CERN-2010-004, pp. 141-166.

Presented at Conference: C09-06-16 Proceedings.

[2] M. Placidi, G.C. Pappas, J. Galvion, M. Orocz. “Update on Kicker Development for the

NGLS”, TUPPR095, Proceedings of IPAC2012.

High Rate Kicker Preliminary Study (Quick Update) Tony Beukers/Tao Tang 4/8/14.

Documents

Transcript of High Rate Kicker Preliminary Study (Quick Update) Tony Beukers/Tao Tang 4/8/14.