2003/ Feb./11-KEKB Review

Interaction Region Design for Super-KEKB
Norihito Ohuchi(1) IR-design conditions(2) QCS and ES(3) Design of the special magnets for the IR (QC1 & QC2)
(4) Belle detector with QCSs and superconducting QC1s
(5) Further study for the IR(1) IR-design conditions(1) The crossing angle of two beams is 15mrad × 2.
(2) βx* = 30 cm, βy*= 3 mm
(3) Final focusing quadrupoles (QCS) locate at the position as close to the IP as
possible. (In order to decide the QCS positions, spatial constraints against the Belle
detector are assumed to be kept the same as KEK-B.)
Pos. from the IP
KEKBSuper-KEKB
QCS-R
1920 mm
1163.3 mm
QCS-L
1600 mm
969.4 mm(4) The QCS magnets are overlaid with the compensation solenoids (ES).
The axes of the QCSs and the ESs are parallel to the LER beam line, and the axes ofthe ESs are consistent with the Belle axis.
(5) The QC1 & QC2 locations are 500 mm closer to the IP than those for KEKB.
(The first trial : iteration to optimize the design of optics and magnets is under way.)Layout of the beam lines near the IP for Super-KEKB

Full Quad.

30 mrad. ofcrossing angle
Full Quad.

IR-right-side-beam-envelope
QCSR : G=37.2 T/mMagnetcenter

ARC

Dist. from Belleaxis (mm)
HER
LER

IP

Viewed from the IP
QCSR

L=0.3327 m

50

Dist. from IP (m)Arc-43.514

0.0-1.3298

Mag. center-36.358

0.0-1.1633

IP-30.540

0.0-0.9968

LER

HER
-100

QC1R-HER : G=14.10 T/m

100

L=0.64 m

Dist. two beams (mm)-50

QC1R-HER

Arc

171.84-4.12

Mag. center

156.95-3.80

IP142.06

-3.48

50

LER
-100100

QC2R-LER : G=2.77 T/m

200

L=1.0 mDist. two beams (mm)-5050

HER-300-400

QC2R-LER-200-100

260.45-6.015

Mag. center

237.23-5.515

IP

214.00-5.015100

LER-50

200

300

400

Dist. from IP (m)Arc

320.75-7.311

Mag. center

306.81-7.011

IP

292.88-6.711

50100

L=0.6 mDist. two beams (mm)-50-100

Dist. from IP (m)Arc

QC2R-HER : G=11.72 T/m

QC2R-HER

Dist. from IP (m)IR-left-side-beam-envelope

QCSL : G=35.4 T/m

L=0.4184 m

Dist. from Belleaxis (mm)HERLER

Viewed from the IP
50

QCSL
HER

LER

-100

Arc-34.494

7.307

1.1788Mag. center-28.370

1.638

0.9694IP-22.204

0.003

0.760

QC1L-HER : G=15.54 T/m

100

Dist. from IP (m)L=0.64 m

Dist. two beams (mm)-50

50

QC1L-HER

LER

Arc

177.24

3.12

Mag. center

154.812.80

IP132.38

2.48

QC2L-LER : G=5.87 T/m
-100

100

L=0.6 m200

Dist. two beams (mm)-5050

HER-400

Arc

283.83

4.599

Mag. center

262.504.299

IP241.16

3.999-100100

QC2L-HER : G=3.37 T/m

L=2.0 mDist. two beams (mm)-50

50

QC2L-HER-100100-50

Dist. from IP (m)QC2L-LER-200-300

Dist. from IP (m)Arc

510.41

7.698

Mag. center

431.156.698

IP360.905.698

LER200300400Dist. from IP (m)500600(2) QCS and ES

QCSL & ESL (viewed from IP)

QCS Parameters

G, T/mL, m
S, mo.p., %ESL

Design
QCSR
QCSL
41.5
41.25
0.33270.4184-969.41163.38482

Optics
QCSR
QCSL
37.2
35.4
0.33270.4184-969.41163.3
7570

QCSL
50LER

HER

100-100-50

QCSR & ESR (viewed from IP)

ES Parameters
ESR

Bz (central field), TL (coil length), mo.p., %ESR
3.00
1.20
43ESL
2.77
0.752
43

QCSR
50HER-100100LER-50

QCSR

Field Profile by ESR, ESL and Belle

Coil-geometryBz-profileC7v4.kdat.for MAC

2437.2

1, Tesla

0SUPER-KEKB

B

z-1-2-3

KEKB-4450.6IP-5-400-300-200

-100

0100

200300s, cm

G profile along the magnet
Bz profile along the LER beam line
QCSR-G-profile.kdat

5040Max. Bz
Right side
Left sideG, T/m

30
20
100-10-40-30-20-100z, cm10203040

Super-KEKB-1.53 T
-1.40 T

KEKB
-4.40 T
-3.20 T400

(3) Design of the special magnets for the IR (QC1 & QC2)
Conventional QC1R-HER

Superconducting QC1R-HER

ø100-100

100200 250

Superconducting QC1L-HER

Conventional QC1L-HER
Magnetic flux lines for super. QC150LER

HER
100-100-50200

Error field in magnet bore
for superconducting and conventional QC1R-HER
conventional
superconducting

G, T/m13.014.99

L, m
0.70.6019

Leak field on the LER beam
In the calculation model:• the conventional QC1R with magnetic shield• the superconducitng QC1R without magnetic shield

O.P. for S.C. QC1R < 20 %Max. field in the S.C. coil =1.23 T
lf.qc1r.v4.0.kdat

qc1rh-6-4.By.txt.kdat

1020error By (conv. QC1R), Gausserror By (super. QC1R), Gauss

By (super.), gauss
By (conv.), Gauss

15by, gausserror By, Gauss

5010

beam area
5beam area

-50-10-60-5-40-200x, mm

20406080100120140160180x-position, mm200220240

QC2R-LERG =2.7 T/m
Bmax < 0.3 T

QC2R-HER

G =12.5 T/mBmax = 1.76 T

(4) Belle detector with QCSs and superconducting QC1s

Field distortion in the Belle detector for Super-KEKB
Super-KEKB(present design)

Bz (central field), T
L (coil length), mESR
3.00
1.20

ESL
2.77
0.752

ESR
5.80
0.616

ESL
4.53
0.461

KEKB
Bz (central field), T
L (coil length), mElectro-magnetic force acting on ESR and ESL from the Belle(force in z-direction)
KEKB
ESR: 7050.5 N (0.7 tons)
ESL: -23505 N (2.4 tons)

Super-KEKB
ESR: 42288 N (4.3 tons)
ESL: -134820 N (13.8 tons)

KEKB-QCSL-Cryostat movement
0.6

QCS-L Cryostat
transverse movement (mm)0.5dy (mm)dx (mm)

0.4

0.3

0.2

0.1

0-0.1
SLQCSL

Skew-Quad.

ZHZVcoil excitation to the design current

(5) Further study for the IR(1) Vacuum chamber design:
Interference with QCSs, QC1s and QC2s
Estimation of SR heat load from QCSs

(2) Optimization of ESR and ESL to reduce the electro-magnetic force from Belle
Mechanical design of the supporting system
Re-design QCSs including the magnetic field induced by ESR, ESL and Belle(3) Detailed design of QC1 and QC2 (superconducting or conventional magnet)
Magnetic profile calculation with 3-D model(4) Detector back ground noise issue