IP Chamber Ver. 1
7th Belle PAC
10 -11 March 2013
K. Kanazawa
forIR Technical Meeting Member
IR Installation Meeting Member
SVD/IR Mechanics Meeting Member

Introduction
The design and fabrication of the IP chamber has been proceeding throughstep-by-step technical tests, with reference to back ground simulation, and withthe evaluation of beam-induced phenomena.
Recently the final design for the version 1 chamber (for BEAST II or Phase2) was proposed.
The following explain the design features.

On Synchrotron Radiation
Au coat, 10~20 µmBeφ 10e-φ 20

Taper: to reduce the number of photons
entering into the central part+
Ridges: to keep the direction of
scattered photons away from Be• Ridges are omitted here to avoid
complex machining. The
connection between the central
part and the crotch part arises
here.
• Instead, this part is slightly bent
downward (in the drawing) toavoid the direct hit of SR fromthe last bend. At present,
simulation shows no serious
scattered photons from this part.

e+On Beam Induced Electro-magnetic Field(or HOM)
φ 20

φ 20

φ 20

HOM due tothe crotch.
(~300 W)φ 20eHOM due tothe taper andthe ridges.
~100 W

φ 10

No trap ofHOM at thecentral part.

HOM due tothe crotch.
(~300 W)

φ 10

φ 20

HOM due tothe taper andthe ridges.
~50We+

On Heat load
The coolant is paraffin. The flow ofparaffin can absorb a heat of ~270W
for a temperature rise of 10℃.
WL: 210W (Ta)e−
WL: 190 W (Ta)SRQ: ~ 50 W
SRB: 100 W

Heat: 400 W.
Water cooling, ID 4 mm, L = 600 cm, v = 2 m/s∆T of water ~ 4°C
Heat transfer coefficient to water: 1.1×104 W/m2/ °C∆T ~ 5 °C (between water and pipe)
The Ta crotch part will be coatedwith Au or Cu (1~2 µm) to reduce
the wall loss.

WL: 70 W (bulk Au)
SRQ: few W

WL: 140 W (Ta)WL: 270 W (Ta)SRQ: ? W
SRB: 130 W

e+T. Kohriki

On Fabrication
HIP = Hot IsostaticPressing•The central
straight partconsists ofdouble tube.
Paraffin runs
between them.
•The connection
between double
tubes is done by
Ti-Ti EBW.
1~2 µm10~20 µm

1~2 µmR&D
Fabrication issue• Cleared– Stress analysis••

For the temperature difference between the two tubes at the center.
Changing support position of beam pipe•
••
•
•
•

Precise machining of Be pipes
NC machining of ridges
Be-Ti brazing
Ti-Ta HIPEBW near by HIP
Pulsed sputter coating of Cu inside 2 cm Al pipe and its uniformity check– Fabrication test•

To be done (in preparation)– Stress analysis•

Check the strength under dynamic force•••

Au coating on Ti pipe
Effect of EBW on the coatingSimulation welding between inner and outer Ti pipe

– Fabrication testScientific issue••

Background simulation
Understanding tip-scattering of photon on a ridge

Cu Sputter Coating Test (S. Tanaka)•Gas: Ar
•Pressure: ~102 Pa•Pulse repetition: 50 Hz•Pulse width: 1.6 µs•Pulse height: ~500 V

Ti pipeBe pipeTi pipeTip-scattering on a ridge (T. Ishibashi et al)~0.14 mm(due to scattering on air)Ta sample
Set up•CHESS (Cornell Univ.) G2 beam line
•Photon energy : 9 keV•Slit : 2 mm (H) by 0.05 mm (V)•Detector angular resolution : 0.2 ° (FWHM)

Half of photons hit the ridge
andthe other half pass over.

Tip-scattering on a ridge

9 keV•The slope of the taper
inside the pipe is 1.23 °.
•The number of tipscattered photons thatenter the central part isless than ~10-7 of those
hit the ridge.
•Assuming the shape ofthe ridge, we will be able
to estimate the actualnumber.

Ratio of the scattered photon.

Ver. 1 Beam Pipe Production Schedule (S. Tanaka)
Start

End

Cupper plating test (for IP
inner tube) (Done)

2012.
92012.
12

Tantalum and titanium partconnection and cutting test(Done)

2012.
1

2012.
12

Crotch part machining(forward)

2013.
4

2013.
7

Crotch part machining(backward)

2013.
4

2013.
7

Tooling production forconnection of IP chamberand crotch part

2012.
12

2013.
3

IP inner chamber
production

2013.
1

2013.
3

Gold plating of inner tube

2013.
4

2013.
4

connection of IP chamber
inner and outer tube (EBWfor Ti-Ti)

2013.
5

2013.
8

Thermal stress test with
EBW and brazing

2012.
11

2013.
3

Crotch part connection(EBW or brazing)

2013.
8

2013.
10

connection of IP chamberand crotch part

2013.
10

2013.
12

2012.
11

12

2013.
1

2

3

4567891011

Yellow: Test
Blue: Central chamberGreen : Crotch partThe outer tube was already fabricated.

12

Concluding remark• The design of the first IP chamber for Phase 2 commissioningis almost completed.
• The total fabrication time will be about 1.5 year, since it
contains many step-by-step fabrication tests.
• The second version can be completed within much shorter
period.
• It will be quite fruitful if we can have a feedback from theexperiences during Phase 2 run before completing theproduction of the second version.