Pulse-to-pulse beam modulation for 4
storage rings with 64 pulsed magnets
Yoshinori Enomoto (KEK)
1.
2.
3.
4.
5.
6.

Introduction
Replacement of magnets
Development and evaluation of pulsed power
supplies
Operation
Plan in FY 2018
Summary
2018/9/19

LINAC 2018 @ Beijing, China

1

Accelerator complex in KEK Tsukuba
PFPF-AR

SuperKEKB HER
SuperKEKB LER

2018/9/19

LINAC 2018 @ Beijing, China

2

Accelerator complex in KEK Tsukuba

2018/9/19

LINAC 2018 @ Beijing, China

4 rings and 1 linac
Two light source rings
PF, PF-ARTwo collider ringsSuperKEKB LER, HER
Parallel configuration
No booster ring
All storage rings
Full energy injection
Top-up injectionKeep intensity of photon constantCompensate short life time
(360sec.)
Two electron gunsRF gun for low emittance injection
to SuperKEKB HER
Thermionic gun for high charge(10 nC) to produce large numberof positrons
Positron injection to LER

Our linac is an all-in-one3injectorRequirements and progress on pulse-to-pulse operation


Slow switch operation (-2009)
PF20 min.

KEB HER/LER

PF

7.5 hours

20 min.

PF-AR
10 min.

KEKB HER/LER
7.5 hours

3 ring injection with DC magnets (2010)
PF pulsed bending magnet (switching magnet) was installed at the end of the linac.
PF-AR
10 min.

PF-AR
10 min.

PF, KEB HER/LER
7.8 hours

PF-AR

PF, KEKB HER/LER

10 min.

7.8 hours

Toward SuperKEKB (2018-)

Very short beam life time in the SuperKEKB rings (360 sec.).
10 min. Interruption is not acceptable.
PF-AR direct injection line was constructed.
Small dynamic aperture
Low emittance beam is required for injection.
RF gun and positron dumping ring were installed.
For emittance preservation, optimization of the optics for each ring is required.

PF pulsed bending magnet

PF, PF-AR, SuperKEB HER/LER
always2018/9/19

Replace DC magnets with pulsed magnets
LINAC 2018 @ Beijing, China

4Requirements and progress on pulse-to-pulse operation

KEKB

SuperKEKB

ChargeEmittance

ChargeEmittanceelectron

1 nC

300 mm・mrad

5 nC

50 (H) / 20 (V) mm・mrad

positron

1 nC

1500 mm・mrad

4 nC

100 (H) / 20 (V) mm・mrad

2018/9/19

LINAC 2018 @ Beijing, China

5Beam energy and structure of our linac

Electron-Positroncommon optics

Replace with pulsed magnet


600 m long, 8 sectors
Maximize common energy section
to use DC magnets as much as
possible
Install pulsed magnets mainly insector 3 to sector 5
26 quads and 26 steerings @ sector 3-5
10 steerings @ sector 1,2
2 quads @ positron production target

2018/9/19

LINAC 2018 @ Beijing, China

6

Replacement of magnets

Maximum design current of steering magnets are 40 A but operated at 10 A

2018/9/19

64 magnets were installed in 2017.
Several types of steering magnets
One type of quad magnet
52 magnets of them were installed as a common unit.
2 x quad magnets.
horizontal and vertical steering magnets
BPM

Movable support
LINAC 2018 @ Beijing, China

7

Requirements for power supplyPF pulsed bending magnet and pulsed power supply
・PF pulsed bending magnet
・Klystron・Electron gunetc. are compatible with pulsed operation.
But most of them are off / on or on timing / off timing control.



Install pulsed power supplies for
28 quads and 36 steerings.
budget is limited

Installation space is limitedCommercial power is limited
Off / On control is notsatisfactory.
Output setting should bechanged pulse-to-pulse
Compatible with MRF event
timing system.
Compatible with EPICS controlsystem.

Decided to develop pulsed power supplies by ourselves.
2018/9/19

8

System configuration of the pulsed power supplies
CSS archiverStandard power supply unit (4 x quad + 4 x steering)
DC power supplyNAS

operater´s machine

PXI express

Pulse driver(for quad)

DC power supply
controll server

Pulse driver(for steering)

DC power supply

cRIO(interlock and data logging)

PXI express(fast controll)pulse driver

event signalmagnet

EPICS CALXI ver 1.3
NI network shared variable
2018/9/19

LINAC 2018 @ Beijing, ChinacRIO(interlock and data logging)LAN

standard unit

9

Timing and fast control


Trigger signal
to ADC and DAC

Optical fiber

ADC NI PXIe-6356
8ch, 16 bit, 1MSa/s
DAC NI PXI-6733
8ch, 16 bit, 1MSa/s

Event receiver
MRF EVR-230



PXI express system is adopted for fast control of thepower supplies.
All of the intelligent functions are processed by PXI
express unit
Pulse driver works as a kind of power amplifier
Separation of control and power section makes it
possible for us to flexible installation of different
capacity of power supplies in the future.
MRF(Micro-Research Finland) event receiver with PXIform factor is used for timing control
MRF event timing system is used as a master timing
system of our linac.
Mode and shot ID information are sent to the event
receiver via optical fiberMode determine the destination of the beam.
Shot ID is used for tagging the data.
10Energy recovery pulse driver for Q magnet
Operation principle of the circuit

ON
IGBT 1load
I

VL (30V)

IGBT 2

C_LV

C_HV

VH (230V)

ONtOFFIGBT 1loadI

VL (30V)

IGBT 2

C_LV

C_HV

VH (230V)

ON

Turn on both IGBTs andcurrent flow from both ofcapacitors.
Turn off IGBT 1 and control
gate voltage of IGBT 2 tokeep constant current
Turn off both IGBTs andstored energy is recovered
to the capacitor (C_HV).

t

Energy recovery+Water coolingOFF
IGBT 1load
I
IGBT 2

C_LVVL (30V)

C_HV

VH (230V)

OFFt

2018/9/19

LINAC 2018 @ Beijing, China

19 inch width
3U height

11

Energy consumption balanceStored energy in inductance

𝑃1𝐿𝐼
2

Ohmic loss per cycle

I𝐼 𝑡

𝐼

𝑎𝑡𝑡

Imax𝑡

t1
𝑃

t2

t1

t

Q (PM_32_4)

ST (PX_32_4)

t1 (s)

2.5 m←

t2 (s)

0.5 m←

Imax (A)300

8L (H)

1m

3m

Rmag (Ω)

7.8 m

115 m

Rtotal (Ω) incl. cable

38.83 m298.85 m

Pjoule-mag (W) @ 50 Hz

760.797

Pjoule-cable (W) @ 50 Hz

302.6

1.275Pjoule-total (W) @ 50 Hz

378.6

2.072

PL (W) @ 50 Hz

2250

4.8

Ptotal (W) @ 50 Hz

2628.66.872



𝑅𝐼 𝑡 𝑑𝑡
𝑅 2𝑎𝑅 2𝑅𝐼𝑡 𝑑𝑡

𝐼𝑡

1𝑡
32𝑡
3

2018/9/19

𝐼𝐼𝑡𝑡





Consumed energy by one quad magnet @ 300 A, 50H z without
energy recovery is 2628.6 W.
Consumed energy by one steering magnet @ 8 A, 50H z without
energy recovery is 6.872 W.
Consumed energy by steering magnet is negligibly small.

𝑡
LINAC 2018 @ Beijing, China

12

Energy consumption balance
30002500076Pjoule-mag

302.6

Pjoule-cable

Consumed energy (measured)

500

Total energy

1000

Loss in cable

1500

Loss in coils

Power (W)2000

Stored energy in inductance

2250

PL

Ptotal827

Recovered energy

2628.6

Measured consumed energy
includes loss in puled drivercircuit and DC power supplies
to charge capacitors

True energy recovery
efficiency (ratio of recovered
energy and stored energy ininductance is better than
80.1%

Pmeasured

Total energy recovery efficiency = 100 x (1 - Pmeasured / Ptotal ) = 68.5%
L energy recovery efficiency = 100 x (1- Pmeasured / PL ) = 80.1%
2018/9/19

LINAC 2018 @ Beijing, China

13

Stability measurement
24 hours stabilityy
25mA/div

Stability measurement for 24hours
Output 166 A and 0 A
alternately
Output current was monitored
built-in DCCT and PXIe ADC.

PF_52_4

0.014578 / 165.946 = 0.0088% (requirement 0.1 % @ 330 A)
2018/9/19

LINAC 2018 @ Beijing, China

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Pulse driver for steering magnet

Apex
PA12

Input buffer

Slew rate limiter

Power amplifier

2018/9/19

LINAC 2018 @ Beijing, China

Bipolar power supply by power Op amp(Apex PA12)
Low efficiency but Simple circuit
Air cooled
2ch / case
Built-in slew rate limiter
15

Pulse-to-pulse injection
BPM data (orbit and charge) for 4 different rings

2018/9/19

LINAC 2018 @ Beijing, China

After the installation,
comprehensive test was donein September 2017.
Pulse-to-pulse operation wasdemonstrated successfully.
For one year (Sept. 2017 –Sept. 2018), the system has
been working very stably. No
severe problem happened.

16Plan in FY2018






2 bend magnets @ merging line.
Shot by shot switch of the RF / thermionic e- gun.
4 quad and 4 steering magnets @ sector A.
To match the beam from the RF/ thermionic e- gun.
8 steering magnets @ inlet and outlet of the arc section.
1 steering magnet @ sector 1 (before the positron production target)
Replace power supply and control system of old 11 steering magnets
19 magnets,30 power supplies will be installed in FY2018
2018/9/19

LINAC 2018 @ Beijing, China

17

Plan in FY2018
2 bend magnet atmerging line
Thermionic e- gun
PF-AR
LER(for e+ production）
PFHER
RF e- gun

2018/9/19

18

SummaryIn 2017, 64 pulsed magnets (28 quad, 36 steering)were installed.
 New pulsed power supply with energy recovery function
was developed.
 Pulse-to-pulse injection to 4 rings were demonstrated.
 The system has been working very stably for one year.
 Further 19 magnets and 30 power supplies are plan to
be installed in 2018.
2018/9/19

LINAC 2018 @ Beijing, China

19

members













K. Furukawa
Adviser, management of the project, timing systemT. Kamitani
Magnet design
F. MiyaharaTiming system
T. Natsui
Energy recovery pulse driver
M. Satoh
Timing and control system, software
K. YokoyamaMagnet design
M. YoshidaEnergy recovery pulse driver
S. UshimotocRIO interlock and data acquisition system
H. Satome
Device driver for event receiver

2018/9/19

Thank youfor your attention!

LINAC 2018 @ Beijing, China20