Pulsed magnet
Y. Enomoto

2018.3.14

The 22nd KEKB Accelerator Review

1Outline
Motivation
 Installation
 Technical features of pulsed power supply
 Present status
 Plan in FY2018
 Summary2018.3.14

The 22nd KEKB Accelerator Review

2Motivation
Shot by shot switch of injection
destination toHER, LER (SKEKB)PFPF-AR2018.3.14

The 22nd KEKB Accelerator Review

3Magnet to be replaced
26 quads and 26 steerings @ sector 3-5
10 steerings @ sector 1,2
2 quads @ positron production target

Beam energy

HER (7 GeV)
PF-AR (6.5 GeV)LER (4 GeV)*dashed line shows positron
PF (2.5 GeV)
ABC

1234

5sector2018.3.14

The 22nd KEKB Accelerator Review

4Installation 1
New magnets were installed in summer 2017.

64 magnets were replaced.

99 working day.
PF was in operation till middle of May
and restarted in October.

Careful preparation was important.

Not only magnet butpower supply
cooling watercablingsupport
control systemsoftware…
were renewed.

2018.3.14

The 22nd KEKB Accelerator Review

5
Photo by N. Toge 2017/3/31

Installation 2

Old DC magnets
Q triplet2018.3.14

New pulsed magnets
QF
Horizontal steering
Vertical steering
QD
The 22nd KEKB Accelerator Review

6Installation 3Standard pulsed power supply setup （1 set = 1 triple rack = 8 ch）
Power supply and interlock
for 2 x Quad + 2 x Steering

Power supply and interlock
for 2 x Quad + 2 x Steering

Control system

Installation work went well.
Long (one month) integrated tests were done in September.
→trouble free startup in October.
2018.3.14

The 22nd KEKB Accelerator Review

7Technical features of pulsed power supply
for quad magnet 1High efficiency
Stored energy in aninductance of the magnet
are recovered tocapacitors.

Total energy recovery
efficiency 68.5％(measured).
High precision and stability
Analog feedback of IGBTs.
0.01％ for 24 hours.

Photo of a prototype pulsed Q driver
Designed by T. Natsui2018.3.14

The 22nd KEKB Accelerator Review

8Technical features of pulsed power supply
for quad magnet 2
Energy consumption balance

Q (50 Hz, 300 A) x 1

3000
2628.62500

Recovered energy

2250

760
Pjoule-mag

302.6

Pjoule-cable

Consumed energy (measured)

500

Loss in cable

1000

Total energy

Stored energy in inductance

1500

Loss in coils

Power (W)2000

PLPtotal

827

Pmeasured.

Energy recovery efficiency= 1 - Pmeasured / Ptotal = 68.5 %2018.3.14

The 22nd KEKB Accelerator Review

9Technical features of pulsed power supply
for quad magnet 3
24 hours stability
25mA/div

0.014578 / 165.946 = 0.01 % (requirement 0.1 % @ 330 A)
2018.3.14

The 22nd KEKB Accelerator Review

PF_52_4

10

Present status
BPM data (orbit and charge) for 4 different rings

Simultaneous injection parameters were established2018.3.14

The 22nd KEKB Accelerator Review

11Plan in FY2018

2 bend magnets @ merging line.
 Shot by shot switch of the RF / thermionic e- gun.

4 quad and 4 steering magnets @ A sector .
To match the beam from the RF/ thermionic e- gun.
8 steering magnets @ inlet and outlet of the arc section.
2 quad and 3 steering magnets @ 1 and 2 sector.
Replace power supply and control system of old 11 steering
magnets @ 1 and 2 sector.



23 magnets
34 power supplies
Will be installed in FY2018→big quantity but …
2018.3.14The 22nd KEKB Accelerator Review

12Plan in FY2018
2 bend magnet atmerging line
Thermionic e- gun
PF-ARLER(for e+ production）
PFHER
RF e- gun2018.3.14

The 22nd KEKB Accelerator Review

13Plan in FY2018

Detailed plan has been made.
Same system as that developed in 2017 will be installed.
→not so much risk even though summer shut down time is 2 month shorter than that in 2017.

2018.3.14

The 22nd KEKB Accelerator Review

14SummaryHigh efficiency and high stability pulsed power supply
was developed.
64 new pulsed magnets were successfully installed
during summer in 2017.
New system has been working without any serious
trouble till now.
Simultaneous injection parameter for 4 rings has been
established.
Installation of 23 magnets and 34 power supply
system is planned in FY 2018.

2018.3.14

The 22nd KEKB Accelerator Review15