IR Overview
M. Tawada
for
IR design group2010.2.15

15th KEKB Review

1

Contents•••••

Design parameters
IR Design
Rotate HER or Belle
Anti-solenoid
Summary

2010.2.15

15th KEKB Review

2Design parameters
KEKB
DesignKEKB Achieved: with crab

SuperKEKB
High‐Current

SuperKEKB
Nano‐Beam

Energy (GeV) (LER/HER)

3.5/8.0

3.5/8.0

3.5/8.0

4.0/7.0

βx* (cm)

33/33

120/12020/20

3.2/2.4

βy* (mm)10/10

5.9/5.9

3/6

0.27/0.41

εx (nm)

18/18

18/24

24/18

3.2/2.4

Coupling (%)

2/21/1?

1/0.5

0.4/0.35

σy(µm)

1.9

0.94

0.85/0.73

0.060

ξy0.052

0.129/0.090

0.3/0.51

0.09/0.09

σz (mm)4~65/3

6/5Ibeam (A)

2.6/1.1

1.64/1.19

9.4/4.1

3.6/2.6

Nbunches

5000

1584

5000

2503

Crossing angle (mrad)

220083

Luminosity
34 cm‐2 s‐1)
(102010.2.1512.11

53

80

15th KEKB Review

3General IR design•

IR design based on Nano-beam scheme•Beam energy was changed to 7x4 GeV– To save the short lifetime for LER•

Crossing angle 83 mrad
– To make QC1 magnets closer to IP– Separated final quadrupole magnets– Use both of superconducting and permanent magnets– Boundary conditions between accelerator and detector are same as thepresent•Angle of 41.5 mrad between HER orbit and Belle– To save vertical emittance increase by anti-solenoid fringe fields

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15th KEKB Review

4

IR design
LER

QC2LP
Horz. FPM

QC2RE
Horz. F
PMHER

QC1RE
Vert. f

QC1LP
Vert. f41.5 mrad

Detector solenoid axis
IP
QC2LE
Horz. FPM

QC1LE
Vert. f41.5 mrad
QC1RP
Vert. fQC2RP
Horz. F

LER and HER beam are focused by separated quadrupole doublet, respectively
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15th KEKB Review5

IR Magnets design•

Use both of superconducting magnets and permanent magnets•Superconducting magnets••

Leakage fields of superconducting magnets are canceled by correction
windings on the other beam pipe•

Warm bore

Permanent magnets for QC2LE, QC2LP, QC2RE••

2010.2.15

Pros.
– Cryostats are small–

Assembly of vacuum chamber can be simple–Vacuum pump can be located near IPCons.
– Need to develop a permanent magnet–Fine temperature control is required–

Extra magnets are required to change beam energies

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IR design with PM version

Anti solenoid-R
QC2LPPM

QC1LE+corr. coil

Cryostat

Cryostat

QC1RE+corr coilIP

QC2LEPM2010.2.15

QC1LP+corr. coil

Anti solenoid-L

QC1RP+corr. coil

15th KEKB Review

N. Ohuchi

QC2REPM

QC2RP+corr. coil

QC1RE7

The magnet design of QC1R/L-P

N. Ohuchi

Vac ch ID 20mm

Magnet Parameters•••••••

Magnet inner radius=22 mm, outer radius=27.55mm
Magnet current=1511 A
Field gradient=75.61 T/mCurrent density, JSC= 1615.8 A/mm2MagneXc length Leﬀ = 0.2967 m
Peak ﬁeld w/o solenoids = 2.24 T Beam envelop
OperaXon temperature = 4.4 K

Cable Parameters•••••

Size =2.5mm × 0.93mm
Number of SC strand=10
Diameter of the strand=0.5mm
Cu raXo=1.8
Ic= 2000 A @ 5T and 4.2 K

Coolant path

SC correctors:
Normal Octupole
Skew Quadrupole
Normal Dipole
Skew Dipole

Cross secXon of QC1 RP
1.123

1.013
0.93

7.0
3.9
2.5

Leakage fields are canceled by the correction
windings on the other beam pipe

1.057
KEKB
QCS

0.967
S‐KEKB
H‐Current

SC correctors:
Normal Sextupole
Normal Quadrupole
Normal Dipole

Designed new SC
cable for main
quadrupole

0.9
S‐KEKB
NanoBeam8

Angle between HER and Belle•

Crossing angle of 83 mrad is determined by QC1•

Not easy to rotate HER orbit with large angle••–

Use existing tunnel–

Small horizontal emittance–Large DAAngle between HER orbit and Belle solenoid axis
–Determined by vertical emittance increase by the fringe field of anti-solenoid–Angle of 41.5 mrad is assumed forthe current anti-solenoid field profile

For anX‐solenoid Ver.2

We have to rotate Belle solenoid axis
if HER orbit can not be rotated2010.2.15

15th KEKB Review

9IR beam orbit (Tsukuba)

A. Morita

Cable Rack
Belle solenoid axis
IP
KEKB-HER

26mradKEKB-LER

SuperKEKB-HER

NIKKO
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SuperKEKB-LER

Concrete shield
15th KEKB Review

OHO
10KEKB Tunnel (Tsukuba)

Cable Rack

Concrete shield
NIKKO

25m

OHO

Reuse KEKB tunnel
2010.2.15

15th KEKB Review11Belle rotation
It seems to be possible technically•

Pros.
– We don’t need to rotate HER orbit– Extra space for PXD/SVD cables and tubes will be available– EM force will be reduced if the radius of anti-solenoid would be smaller

•

Cons.
– Expensive (3 oku yen for belle rotation)– Need to modify the concrete bases and shields– Belle people worry about the damaging CsI calorimeter

We don’t reach a consensus

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○ Belle Detector
8m(W)×8m(L)×10m(H)Total weight: 1300tons
650tons (Barrel Yoke)
600tons (End Yoke)
50tons (Others)

H. Yamaoka

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1313

Belle rotation

Need to modify the concrete base and shields inorder to rotate Belle detector
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14Anti solenoid

H. KoisoVertical emittance degradation depends on the anti-solenoid fields profile

AnX‐solenoid Ver.2
HER:53mrad

ΔεyBz

€

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15th KEKB Review

15Anti solenoid
Issues for anti-solenoid•Bx components degrade vertical emittance performance–•EM force for anti-solenoids is better––•

LER Δεy=+5.8pm (+0.18% for 3.2 nm) for 41.5mrad
SuperKEKBKEKBS-R= 20.4 kN, S-R= -22.6 kN
S-L= 22 .0 kN, S-R= 2.8 kN

COD

We need to find a better solution for anti-solenoid

22.6 kN

20.4 kN
Anti-solenoid ver. 2
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15th KEKB Review

16Anti Solenoid
Anti-solenoid ver. 3

EM forces are acceptable31.2 kN< 40 kN
S-R=-22.6 kN → 31.2kN
S-L= 20.4 kN → 26.2kN
26.2 kN

Bx = −1 ∂Bzx2 ∂z

Gradients can be reduced€2010.2.15

15th KEKB Review

17

IR vacuum chamber

K. Kanazawa

Positron• Vacuum level will be worse due to poor vacuum conductance.
• IR assembly is a big issue• BPM can’t be ﬁxed rigidly on the quadrupole magnet
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Physical Aperture•

Required acceptance for injection– 2Jx=5x10-7 (m), 2Jy=2x10-8(m), 4% coupling– Dynamic effects are ignored because nominal νx = 0.53•

Physical aperture is not enough for the design β-functions– COD is not taken into account– No margin for errorQC1LP

QC1RP

QC1LE

QC1RE

QC2LP

QC2RP

QC2LE

QC2RE

Physical 20
Aperture
(mm)

2030

3060

60

7070

Required 11.2
Aperture(Horz.)
(mm)

10.0

16.4

17.2

25.6

28.4

47.6

48.4

Vert.
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(mm)

14.8

18.2

18.2

9.4

9.6

15.4

10.6

15.8

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19A. Morita

COD (Belle)
COD in Belle detector depends on the solenoid field profile
COD(LER 41.5 mrad)

COD(HER 41.5 mrad)
100um

200um

4mm

QC2LE

IP

QC1LE

15th KEKB Review

QC1RE

QC2RE

QC2LP

QC1LP

QC1RP

QC2RP2010.2.15

IP1mm20

Summary•

IR design based on Nano-beam scheme•

Beam energy: 7x4 GeV and crossing angle: 83 mrad•

The design work is on-going•

Issues– IR magnets (N. Ohuchi)– Vacuum chamber and assembly (K. Kanazawa)– BG simulation for Belle (M. Iwasaki)– Vibration measurement (H. Yamaoka/M. Masuzawa)– Rotate HER orbit or Belle detector– Estimation of the beam loss rate at IR– Optics simulation with error

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21

Spare slides

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AirPad@CMS

駆動式エンドレス滑り装置JES(オックスジャッキ（株）)
hip://www.oxjack.co.jp/modules/general/index.php?acXon=view_product&product_id=66

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15th KEKB Review23

Rotate Belle and base frame
How to:1. Support Belle and base frame temporaly
2. Remove old wheel

Barrel Yoke
End Yoke

3. Remove hydraulic machines

Base frame

4. Rotate belle and base frameWheel

B

5. Aiach new support equipments
6. Put hydraulic machines
7. Put on the new wheel

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