Main Ring Magnets
M.Masuzawa

1. Overview
2. Magnet design & fabrication Status
3. Dismantling Status
4. Survey & Alignment Status
5. Other issues
6. Summary
7. Power Supplies
by T. Oki

1. Overview
Magnet design & measurements
Installation, survey & alignment
K. Egawa
M. Masuzawa I am still the newest
Y. Ohsawa
member even after ~15 years.

Power supply design, tuning
Installation & Cabling
T. Kawamoto
T. Sueno+ T. Oki
N. Tokuda

Superconducting magnet
Design & measurements

N. Ohuchi+ M. Iwasaki et al.
N. Ohuchi

1. Overview“3/3” Nano-Beam Scheme• LER vacuum pipes need to be replaced by new ones with antechambers.
All LER quadrupoles and sextupoles need to be opened up(& put back together).
• LER main arc dipole magnets need to be replaced.
From Leff 0.89 m ⇒4.19 m• More wiggler magnets with shorter pole length.
Different wiggler layouts to achieve shorter wiggle period.
• Completely different LER/HER beam lines in the Tsukuba
straight section.
• New wiggler section needs to be added in the HER.
• Vertical steering magnets need to be replaced by wider ones inthe LER.

1. Overview“3/3” Nano-Beam Scheme• Alignment strategy– Connecting the existing beam lines with the new beam lines (Tsukuba straightsections)– New IR magnet system
working closely with the IR group (N.Ohuchi et al.)– IR movable table needs to be newly designed.

• Cooling water system needs to be strengthened especially for
the wiggler sections (Nikko and Oho straight sections) as weare operating the cooling water system at almost 100%
capacity level already.
The utility group (M.Ono et al.) is in charge of the coolingwater system upgrade.

2. Magnet design &fabrication Status

2. Magnet design &fabrication status

More than 400 new main magnets needed andmeasured by T=0, to circulate beam in the rings
LER#

Calls for bids
for LER
dipoles,
wigglers andsome otherquads havebeen sent out.
They will bemade by theend of Mar.
2012.

Specifications
not finalized forsome of the
Tsukubastraight section
magnets.

2

leff
0.3444

10
14
100
112
56
10
37 + 16
8
328
HER
#
14
7
1
38 + 2262

3.9896
4.189544
4.189544
0.21340.34347
0.31374
0.58372
0.334

43

0.56

2
200 + 74108

1.12
0.82615
0.334

leff

mag.namek-0.000592 BC1LP
0.043706 BL0&7,BS2
0.0799998 BL1~5,9
B2P
0.0560999
0.01118 BW0NRP.1
BW3NRP.1
0.000993 QKALP-0.3274108 QC3LP
SL

B, B' or B"-0.022935

comment
new

0.146170.254780.17866
0.69902

new B.lc
new B.arc
new B.arc
new half_pole_WH
new single_pole_WS
new
LER_Q_rf + newnew

mag.name-0.04 BL1LE
BC*
0.0034541
0.0019022 BC3LE
BW2ORP.1
0.0001669 QKALE-2.77E-05 QKDLE

B, B' or B"-0.26685
0.267630.13634k

40.34440.3723
0.3462
0.34440.37230.3345958

QC3LE-0.6670868 QL9LE-0.326735 QSATLE
0 SO2TLE.1

0.04223-7.48390.012932-1.99E-03

comment
LER new B.lc
newnew▛▜_kb_wigg + new
new
new_Qsk

15.944new_wide ? (kb_Qarc)-15.894-10.554

new wide ? 2×0.56m
kb_QA 199+2 + new
new or kb_SxF

2. Magnet design &fabrication status

LER arc dipoles & new wigglers
parameters

Magnet type

Mag.
name

Leff [m]B[T]countsComparison withKEKB

Arc dipole

B2P.1~100
BL(1~5)R/LP

4.18950.17866
0.25478100
14(+2)

Longer, weaker
LER Local
correction

Localcorrection

BL*R/LP

3.98960.1461724(+2)

LER/HER
Local correction

Wiggler

BW0*.P

0.21340.69902112(+2)

Half pole

Wiggler

BW1*.P

0.34347

0.6990256(+2)

Single pole

Why not the same length, to makefabrication (and contract) simpler?
Arc dipoles, as long as possible!
from the emittance point of view.
But they are ~20cm too long to fit in
the new IR straight sections.

2. Magnet design &fabrication status

LER Dipole maget
surveying planeside plate
120
240

53 mm
min. gap (half)

120

225

115

55 mm
center gap (half)

for B.arc : J / pole = 840A × 10 = 8400A
for B.lc : J / pole = 1325A × 10 = 13250A / pole
pole proﬁle unit [ mm ] ( preliminary）
x coordinate : ‐120. ‐115. ‐85. ‐75.
y coordinate : 55.
53. 53.
55.

78.
55.

88.
53.

115.
53.

120.
55.

beam pipe and the cross sec6on of new LER dipole

K.Egawa2. Magnet design &fabrication status

Wigglers•Reduce wiggling pitch ⇨ 1/2•Increase KEKB type wiggler peak field
0.77 T ⇨ 0.98 T•New wigglers (“half pole” and “single pole”, bothwindow frame type ) must fit in the very tight space(transverse direction)
half pole

KEKB wiggler
double pole

single pole

KEKB wiggler
double polehalf pole

K.Egawa2. Magnet design &fabrication status

Steering magnets
to be manufactured & measured
or to be modified for SuperKEKB

Magnet type

Mag.
name

Eff. length[m]

B・Leff[T・m]countsComments

LER
Verticalfor arc sec.

ZV*P

0.344+α~0.012

Only for
QD~210

Wider gap for
antechamber
160 ⇒ ~290 mm

LER
Horizontal
for arc sec.

ZH*P

0.344

0.02

Only
For QF~210

Rotate LER ZV*P by
90°
new supports

HER
Verticalfor arc sec.

ZV*E

0.344+α0.02?

Only for
QD~290?

Wider gap for
antechamber
160 ⇒ 240 (?) mm

HER
Horizontal
for arc sec.

ZH*E

0.344

0.03

Only
For QF~210

Rotate HER ZV*P by
90° for wider
good field region
new supports

KEKB quads were accompanied by both verPcal and horizontal steering magnets.
But SuperKEKB quads will only have one type to reduce cost.
Power supplies for corrector magnets will be reused to reduce cost.
The price we pay is the kick angle.
>200 new cor. magnets
Max. kick will be 0.012/0.02×3.5/4 (~0.5) for ZV*P.
Max.kick will be 3.5/4 for ZH*P.

>400 new supports

3. Dismantling Status
Introduced by Akai-san yesterdayMain work in the KEKB tunnel
~Sep.
2010
LER B removal
Wiggler removal
Steering removal
Vacuum pipe removal(open&close Q & Sx)
OthersAir pallet overhaul
Designing new tools
Draining cooling waterfrom the magnets to bereused.

Oct.

Nov.

Dec. Jan.
2011

Feb. Mar.

3. Dismantling
StatusOct. 28, 2010 Dismantling started officiallyAug.21st , 1998 Former director general H. Sugahara
tightening the gold-plated bolt (of the last magnet)

Aug.21, 1998
Oct.28th ,2010
Director General A.Suzuki, Accelerator Division
Director K.Oide and others, loosening the bolts ofthe same magnet.

Oct. 28, 2010 Oct. 28, 2010

Oct. 28, 2010

3. Dismantling
StatusAir pallet in full action
1st magnet carried out by air pallet on Nov. 11th ,2010

Air pallet being overhauled last year.
Most of the magnets(which needed to be
removed) & some
vacuum pipes werecarried out using the
air pallet.

3. Dismantling
StatusWorking in between the inner (remaining) HER
beam line & the cable racks at the Nikko cavity
section. We did take them out.

Opening LER sextupole
magnet to remove the vacuum
pipe using the tool newly
designed.

HER
LER
The magnet group has carried out 342 vacuum pipes
so far (mostly those inside magnets), each probably~2m long and more than 40 kg.

3. Dismantling
StatusLess crowded & much lighter tunnel
and much more crowded storage area.
We are sufferingfrom a lack ofstorage area.

Magnettype# of Mag.
removed fromKEKB so far

MagWeight (t)Net
Weight (t)comments

LER B

107

~3

~320

~30 magnets will be reused at SuperKEKB.
Looking for someone who can use them.

Steering

860

~0.4

~340

~60% of them will be reused withsome modification. Looking for someone who
can use them.

Wiggler

134

~3

~400

~20 still remains in the tunnel.
All wigglers will be reused at SuperKEKB.

>1000

Vacuum pipes (& the solenoid coils) are
not included.

4. Survey & Alignment Status•Main ring
•Strengthened geodetic network•IR•Analyzed floor motion during the Belleroll-out.
•Strategy for cryostat alignment

4. Survey & Alignment
Status : Main Ring

Monument survey
When the KEKB magnets were first installed in
the TRISTAN tunnel in 1997, there was no
sophisticated geodetic network to be used.
There were only floor monuments, which indicate
the central positions of the removed TRISTAN
quadruple magnets,
every ~8 m.
Now some are covered by the KEKB magnets,
cables, supports…
We need more monuments which we can see.
Need for new geodetic network
Added more monuments and surveyed themalong with the KEKB magnets.
We need to understand the present positions of
the KEKB magnets as most of the magnets in thearc sections will remain in the beam line.

4. Survey & Alignment
Status : Main Ring

Newly added monuments
installed on the wall, floor and so on

Very difficult to find space for stable monuments.
Our tunnel is ~3 decade old.
Experienced two generation accelerators,
TRISTAN (single ring)and KEKB (double ring, more crowded).
Lots of junk (cables, pipes,,,) not much space especially on thecable rack side.

4. Survey & Alignment
Status : Main Ring

New geodetic network

The surveying network is constructed as
successive unit rectangles, ~8 m in lengthand ~2 m in width.
~32 m long area (4 unit rectangles) wascovered by one tracker setup (station).
Survey results, next

4. Survey & Alignment
Status : Main Ring

Tunnel is deformed horizontally & vertically
S=0~2 mm jump in both X and Y@expansion joint.

Y
X

S=1500South arc continues to sinkat an average rate of ~2 mm/year,
though the rate seems to vary year to year.
The reason why this particular partof the tunnel sinks is not known.

Optics people say
Overall leveling is not needed.
Just smoothing out locally.

4. Survey & Alignment
Status : Main Ring New look of the Tsukuba straight section

Lattice not finalized yet

IPLeft side of the IP

Grey lines :KEKB LER/HER beam linesPlan:
All the magnets (~150 B,Q,Sx)
to be taken out by the end of summer,
followed by the power cable removal.
Tunnel floor repair.
Survey for defining the new LER/HER
magnet positions in the summer.

IP

Baseplate installation.

Right side of the IP

4. Survey & Alignment
Status : IR

Beam line & floor motion during Belle roll-out analyzed.
This should be taken into account when evaluating the alignment
tolerances (or/and the specs for QC correction coils) for SuperKEKB
QC’s along with the cryostat motion due to the electro-magnetic force
when Belle solenoid/QCs are being ramped up.

~1300 t4. Survey & Alignment
Status : IR

Beam line floor & Cryostat (retracted) motion

4. Survey & Alignment
Status : IR

Horizontal motion of the B4 floor & beam line floor& Cryostat (retracted)

12/9 10:00
5m
QCSR
B4 Floor
QCSL

4. Survey & Alignment
Status : IR

Horizontal motion of the B4 floor & beam line floor& Cryostat (retracted)

12/9 11:00
10m
QCSR
B4 Floor
QCSL

4. Survey & Alignment
Status : IR

Horizontal motion of the B4 floor & beam line floor& Cryostat (retracted)

12/9 11:30
13m
QCSR
B4 Floor
QCSL

Final position

4. Survey & Alignment
Status : IR

Horizontal motion of the B4 floor & beam line floor& Cryostat (retracted)

12/9 14:00
QCSR
B4 Floor
QCSL

4. Survey & Alignment
Status : IR

Horizontal motion of the B4 floor & beam line floor& Cryostat (retracted)

12/9 17:00
QCSR
B4 Floor
QCSL

4. Survey & Alignment
Status : IR

Horizontal motion of the B4 floor & beam line floor& Cryostat (retracted)

12/10 9:00
QCSR
B4 Floor
QCSL

Belle pulls the beam line with it.

4. Survey & Alignment
Status : IR

Vertical motion of the B4 floor

12/9 10:00
5m

4. Survey & Alignment
Status : IR

Vertical motion of the B4 floor

12/10 9:00
13m
after
~22 hours

Experimental building floor (B4 floor)
tilts towards Belle4. Survey & Alignment
Status : IR

Dec. 9th 9:00
Bell in the beam line
Before rolling out

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 9th 10:00
Rolled out 5m

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 9th 11:00
Rolled out 10m

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 9th 11:30
Rolled out 13m
Final position

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 9th 14:00
3 hours from
Roll-out completion

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 9th 17:00
6 hours from
Roll-out completion

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 10th 9:00
22 hours from
Roll-out completion

Vertical motion of the beam line floor & cryostat (retracted)

4. Survey & Alignment
Status : IR

Dec. 9th 14:00
3 hours from
Roll-out completion

Tsukuba experimental hall

KEKB beam line

B4 floor
KEKB beam line opens up likea drawbridge when Belle moves away.

5. Other issues•Skew quad windings on Sextupole magnets•Rotating sextupole magnets (physically) by
as much as ±30 degree•IR movable table design
Not too muchthought has been•…
put in but

5. Others

Rotation of normal conducting sextupole
magnets (700kg and up)
Challenges:
Range ±30 degree
Good reproducibility
Small backlash
Rotate with heavy cables?
Rotate with cooling pipes?
Mechanically stable
R&D is scheduled from April.

6. Summary
KEKB tunnel dismantlingAlmost done except for Tsukuba straight section, a part of Oho wiggler
section and the Fuji test beam line.
Magnet design & fabrication on-going.
LER dipoles, wigglers, some quads, LER V-steering.
~100 main magnets still need to be fabricated.
Magnet measurement systems need to be prepared and tested.
We plan to evaluate all magnets at KEK except for V-steering.


Survey network expanded.
Monuments increased.
Tunnel deformation observed (needs to be monitored during theconstruction?)Effects of Belle roll-out examined and will be fed back to the IR alignment
strategy, QC cryostat fiducialization, QC correction coil specs…


R&D on sextupole magnet rotation will start soon.
And of course, the power supply systems Next speaker.
I need another member （教官、技官）in my group.

Upgrade plan for
Magnet Power Supply System

T. Kawamoto
T. Sueno
N. Tokuda
T. Oki16th KEKB Accelerator Review Committee

Contents- Power supply buildings- Cables- Power supplies (existing / to be developed)- Typical data (stability / ripple)- R&D

Power supply buildings

8 power supply buildings.
More than 2300 power supplies exist for KEKB.
The PS buildings are already very crowded.
We requested additional space & power receiving and distribution facilities.

and hole…

Cablesfrom power supplies
follow thru a pit…

into KEKB tunnel
via rack,then connected tomagnets.

How much of the cable we can recycle is not clear.
(Can we pull out the cable at bottom of everything else ?)In order to replace the cables, identification of each cable is necessary,
before cutting, pull out, extend and joint cables.

Existing Power supplies
We have ~ 2300 power supplies:Class# of power supplies

Typical load

Small class(< 10 A, 0.5 kW)

1885

Steering magnet etc

Medium class(< 500 A, 100 kW)

368

Local Quads

Large class(< 500 A, 500 kW)

14

Quad families

Very old MW class(< 1250 A, 1 MW)

6

Bending and Wigglers

Typical spec.
Stability< 20 ppm / day

Ripple< 10 ppm

Setting error< ± 50 ppm (16-bit DAC)Existing Power supplies
We have ~ 2300 power supplies:Class# of power supplies

Typical load

Small class(< 10 A, 0.5 kW)

1885

Steering magnet etc

Medium class(< 500 A, 100 kW)

368

Local Quads

Large class(< 500 A, 500 kW)

14

Quad families

Very old MW class(< 1250 A, 1 MW)

6

Bending and Wigglers

Small and Medium class power supplies will be reused for SuperKEKB
after appropriate maintenance and overhaul.
-10 years old / frequently broken parts should be replaced.
- Switching module is out of manufacture,and compatible module may be use after modification.

New Power supplies to be developed
Except for the PS for Bending and Wigglers, the spec. has not been fixed.
Power# of power supplies

Typical load

0.95 MW (860 A)

2

B (HER / LER)

< 0.98 MW (1400 A)

8 (+ 8)

Wigglers (LER) (HER?)< 500 kW (500 A)(~ 14)

Q families (HER / LER)

< 100 kW (500 A)(~ 50)

Local Q (HER / LER)

~ 10 kW (1000 A)(~ 10)QCS main~ 0.5 kW (± 50 A)(~ 50)

QCS correction(Max. 540 kW

many

Damping Ring)

Target spec. for B and Wigg.
Stability< 2 ppm / day

Ripple< 1 ppm

Setting error< ± 0.1 ppm (~23-bit)

Typical long-term stability
Prototype power supply for QCS main coilPower supply: Transistor-dropper type (1000 A-30 V).
Test Load: 1.2 mΩ resistor
15℃‐

Temp: 20 〜27.5 ℃

25℃‐

Initial drift
9 ppm

Stability: 11 ppm / 24 hrs.

24 hrs.

How much jitter on the measured current
For precious control, lower jitter is necessary on the current monitoring.
Current is measured by a DCCT and a DMM.

Fluctuation (σ) of DCCT
output during 5min (µV)

Power supply: Transistor-dropper type (1000 A-30 V).
DCCT: 1000 A / 10 V output
DMM: KEITHLEY 2002 (10 PLC, 20 V range)
10
10 µV corresponds to 1 ppm

8
6
4
2

Noise level: 0.6 µV

0
0

200

400 600 800
Current (A)1000

Typical ripple
QF4E magnet system
Power supply: Transistor-dropper type (500 A-380 V).
Load: 40 Quads connected in series around KEKB ring.
Measured voltage ripple

Measured load impedance

50 Hz 300Hz

Z ~ 0.66 Ω + 0.58 H ( f < 1kH)
50 Hz: 0.7 ppm
300Hz: 0.3 ppm

R&D
For more precise setting / monitoring of the current,
increasing the DAC bits from present 16 to 20 or more is necessary.
Two methods are considerable.
1. Two 16-bit DAC’s are combined.
1/216
2. Try new commercial use 20-bit DAC. (AD5791)
For long-term stability improvement,
precise DCCT in an oven and Digital Multi Meter
may be used for digital feed back control.
These R&D has been started andpreliminary results will be obtain until this April.
Ripple reduction study may also be required.

1/216

Schedule as summary
FY2010 (H22)FY2011 (H23)FY2012 (H24)

FY2013 (H25)

FY2014 (H26)

FY2015 (H27)

4 5 6 7 8 9 # # # 1 2 3 4 5 6 7 8 9 # # # 1 2 3 4 5 6 7 8 9 # # # 1 2 3 4 5 6 7 8 9 # # # 1 2 3 4 5 6 7 8 9 # # # 1 2 3 4 5 6 7 8 9 # # # 1 2 3

R&D
Higher bits
Digital feedback
Precious monitoring

Power supply
QCS prototype

install

Load test

B (H/L), Wig (L)Design and development

Q, Sx (L/H), Wig (H)Design and development

QCS collector

Design and development

QCS main

Test with load is strongly depends on the progress ofcooling water, vaccum, control, magnet and cable installation

Install

Load tests and tuning

Design and development

Damping ring

Design and development

Steering etc

MaintenanceCovering PSs with dehumidifierParts replacement

Medium class and Small class PS (IPM, capacitor, ...)

Facility
Buildings for power supplies

DesignConstruction

Electric transformer substation
Cables (ID, removal, buy, install)
Re-arrengement of PSs

Reinforce Oho substation
buy cables

buy cables(buy cables)

Reinforce Nikko substation
Install cables and cooling pipes, system checkBack-up slideDigital feed back control+

Setting value
in 16-bit (major)

DAC
-

1/216

+

Setting value
in 16-bit (minor)

+

-

DAC

Error Detection
DMM
DCCT
N
P
Output terminal+

current loop-

minorvoltage loop+-

FY2010 (H22)FY2011 (H23)FY2012 (H24)

FY2013 (H25)

FY2014 (H26)

4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3Magnet System
Power supplies

B(L/H), Wiggler(L)Q and Sx(L/H), Wiggler(H)Cables, cooling pipes

buy cables

buy cables(buy cables)

QCS
QCS R&D and design
Power supplies for QCS

QCS R&D and design
PS for collector magnets

Damping Ring
Power supply for magnets

Power supplies

PS for main magnets

Install cables and cooling pipes, system check