Beast運転について

Detector
Rotation
Two beams have finite crossing angle (83mrad).
Belle solenoid axis must be bisector of the angle, but now it is not.
Either Belle or two rings must be rotated.
Parameters may be OLD
Rotation is technically possible.
Additional cost (very preliminary estimate: 3 oku yen)
Possible damage in detectors (?)
Concern from bad experience of buckled CsI container when constructing Bel
We will rotate Belle IF two rings cannot be rotated after all.
Cost to be covered by machine group.
1
2011 BPAC Ushiroda
Beam axis and Solenoid axis
KEKB LER
GY
*GY is parallel to OHO/NIKKO
straight section.
GX is perpendicular to GY.
KEKB HER
SuperKEKB HER
SuperKEKB LER
50 mrad
= 41.5+8.5 mrad
4.55 mrad
-17.45 mrad
GY
New BELLE
Solenoid?
GX
-33 mrad
GX
BELLE
Solenoid=LER
What is the Belle solenoid axis ?
Solenoid axis is:
(a) 8.5 + 17.45 -> +25.95 mrad
(b) or no solution to rotate BELLE
2
2011/Feb Ohnishi
現状の曖昧な点
• 何時
• 誰が
• どういう条件で行うか？
– Belle EBの決定では加速器が回転しない方法を
議論したうえで、どうしようもない場合に最終決定
となっている。（ここが曖昧）
Two kinds of ideas are proposed.
Yamaoka
- Beam level should be kept to
the same as present.
- No impact to the B-CsI.
Chosen!
A. - Replace to new rollers
B. - Replace to new moving system
- Use: Current hydraulic system
- Current hydraulic system
(Disassemble  Recovery) is necessary.
is unnecessary.
Cost: A < B
4
Procedures (Preliminary)
This work will be done after roll-out/uninstall detectors.
- 4-5 months is necessary
1. Remove: Hydraulic system
2. Set: lifting jacks/sleepers
3. Lift the Belle and replace to new rollers
5
4. Preparation (Set jacks, Teflon
Jack
sheets/Air-pads)Teflon sheets
5. Carry out rotation  Recover hydraulic system
6. Finished
6
他にやる事
干渉!
再配管!
干渉!
干渉!
・B-CsIの保護
・検出器の床面への固定
7
Beast II
Sven Vahsen (Hawaii), S.Tanaka(KEK)
(各sub-part代表）
Beast
From the point of view on Belle BG estimation
• We want to know the BG level before data taking.
– On Belle commissioning, there were some holes of BG
shielding.
– On superKEKB case, we should investigate BG rate of
– Tauschek、
– SR、
– Radiative Bhabha,
– two-photon
• Purpose:
– Validation of each BG rate,
– Tuning of Beam Optics
How to operate ?
• There are three scenario at this moment:
– No magnetic field of Belle solenoid(Belle roll-out position)
• Need to power up of skew magnets and add steering magnets.
• Beta function will be around 1 order high .
• Fine optics tuning and estimation of realistic BG rate will be hopeless.
– Prepare another solenoid magnet(1.5T) (Belle roll-out position)
– It will take additional cost (1.2 M$)
– Still needing another optics tuning
– BG study can be done.
– Roll-in Belle detector without Tracking detector
– Start-up of Belle detector will be delay
– We can study real BG rate.
– On Belle case, start-up of Beast operation was considered as
start point of Belle.
Beast II operation
• Situation:
– Beam pipe (real setting on IP, crotch part made by SUS)
– Solenoid on ->Real BG situation
• We may study about "Beam Abort setting for PXD"
– no CDC ->no chance to check RoI algorithm
– We may study "the beam Injection BG" and beam dumping time
– We can optimize the movable beam mask to reduce BG
(@KEKB control room)
– We can measure beam gas BG depending on vacuum level.
– If some PXD ladder can be installed, we may check cooling system
operation (optimizing operation procedure and alarm setting)
– Slow control system check.
– Triggering test by ECL or KLM
– If IP chamber can displace, we may check SR situation.
整理しなおすと
• BEASTII can be divided to two stages:
1,Just studying BG level and checking sensor response(like BEAST).
ex.: SR, Touschek and beam gas BG, Beam injection noise,
Luminosity monitor (output to BG simulation)
On this stage, each sub-part may study individually.
• 2,Pre-commissioning stage:
a, Trigger(ECL,KLM will be ready),
b, Luminosity feed back to optimize beam orbit control,
c, Beam injection veto(sending veto signal to trigger system
on beam injection, which is critical subject on PXD system.)
d, Movable beam mask optimization to reduce BG
e, KEKB beam abort setting by each sub-detector
As a result, all sub-detector(+machine) should join to BEASTII operation.
(Therefore BEASTII is assigned to common session on next B2GM.)
Belle側では各サブデテクターの方にどのような試験がしたいか聞いている段階
今後の予定
• 11月のB2GMで加速器との合同打ち合わせを
したいと考えてます。
（何をしたい、組み入れたい装置などアイデア募集中）

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