IR assembly + BG simulation 2009/7/7 M. Iwasaki (Tokyo) For Belle-II MDI Group Tokyo / Tohoku / KEK

Transcription

1 IR assembly + BG simulation 2009/7/7 M. Iwasaki (Tokyo) For Belle-II MDI Group Tokyo / Tohoku / KEK

2 1. IR assembly

3 IR assembly at current KEKB K.Kanazawa (KEK) IP beam pipe + SVD are connected with QCS beam pipe first Condition: Vacuum chambers are separate from QCS cryostats. Step 1: Connect the front half of QCSL chamber and QCSR chamber to IP chamber that is already set at the interaction point. (The end flange of QCSR chamber is temporally removed.) Step 2: Move forward QCS cryostats. Step 3: Connect the end half of QCSL chamber with a magic flange to the front half. Attach the end flange to QCSR chamber.

4 N.Ohuchi (KEK) Super-KEKB : QCS beam pipe and cryostat are integrated SVD/PXD/IP-beam pipe will be connected with cryostat directly

5 IR assembly R&D Problem QCS beam pipe and QCS cryostat will be integrated SVD/PXD/IP-beampipe should be directly connected with QCS cryostat How to connect 1. Remote-controlled vacuum fitting 2. TAIKO chamber 3. All components (SVD/PXD/beampipe/QCS) are integrated

6 Remote-controlled Vacuum fitting CDC PXD/SVD + IP beam pipe

7 Remote-controlled Vacuum fitting CDC QCS cryostat

8 Remote-controlled Vacuum fitting CDC QCS cryostat

9 TAIKO chamber

10 TAIKO chamber S.Uno / T.Kohriki CDC PXD/SVD + IP beam pipe

11 TAIKO chamber S.Uno / T.Kohriki CDC TAIKO chamber

12 TAIKO chamber S.Uno / T.Kohriki CDC Cryostat TAIKO chamber

13 TAIKO chamber S.Uno / T.Kohriki CDC RF contact Vacuum seal

14 RF contact By Y. Suetsugu

15 Parameters are not fixed yet T.Kohriki (2009/07/07 version)

16 All integrated?? There are huge components related to the superconducting magnets.. Original drawing: R. Sugahara

17 IR assembly : current status Members: KEK T.Kohriki + Machine shop Strategy: 1. R&D of remote-controlled vacuum fitting (~ 0.5 year) If this method seems technically impossible 2. TAIKO chamber (~0.5 year) If this method seems technically impossible 3. All components are integrated - In case, Belle should support QCS near the IP, TAIKO chamber might be the good candidate

18 2. Detector BG

19 Detector BG High current option Nano-beam option SR (upstream) SR (back-scatter) Radiative-BhaBha Touschek Beam-gas Much higher Large beam size at Q Very high current Higher Strong QCS B-field Higher Larger crossing angle Strong QCS B-field Higher? Small beam size Higher Very high current Lower? Higher? Small beam size at Q But large bending magnet Much lower No QCS bending Much lower Large crossing angle, but no QCS bending Much higher? Very small beam size Higher? High current QCS High-current QCS Nano-beam HER beam LER beam HER beam LER beam

20 Detector BG study -To design the beam pipe, SR BG estimation is important SR mask / beam-pipe geometry design We estimate the SR BG first -Other BG sources will be studied later Touschek, Beam-gas, radiative BhaBha, -For the BG studies, we construct the beam-line simulation based GEANT4 developed by K.Tanabe and T.Abe of U.Tokyo B-field of magnets + (Simple beam pipe + 1 st layer SVD ) The number of particles in a bunch (Nano-beam option) HER : 2.7A / (1.6*10-19 )/(100kHz)/3450 = 0.5 *10 11 LER : 4.6A / (1.6*10-19 )/(100kHz)/3450 = 1.0 *10 11

21 Relationship between Belle-II and Super-KEKB: Nano-beam Parameters are not fixed yet Crossing angle : 22mrad 60mrad e - Super-KEKB HER(e - ) axis 30mrad (in MC) Belle solenoid (not fixed) 30mrad (in MC) LER HER e + Super KEKB LER(e + ) axis Beam pipe : parallel to HER? Belle solenoid? Or??

22 IR Layout : Nano-beam (2009/4) HER Beam LER Beam

23 QC1R magnets: Nano-beam QC1RP QC1RE Inner radius =10.5mm QC1RP QC1RE HER Beam LER Beam

24 Beam pipe example : Nano-beam Parameters are not fixed yet As of May, 2009 K.Kanazawa 200mm φ20 HER IP LER φ20 Beam pipe To connect with the separate Q magnets the IP beam pipe has branch structures (crotch structures)

25 HER beam-line simulation B0S QC3R Nano-beam option e+ e- γ QC2R QCSR QCSL QC2L QC3L B0SM HER beam

26 HER upstream x10 6 Nano-beam option 5σ beam SR (reached to the IP) production position Z-position(cm) SR energy (at IP) Nano-beam HER SR energy ~ 1/10 High-current SR 10 kev 50 kev (Vertical scale: Scaled for 1-bunch beam) Energy(MeV)

27 HER beam-line simulation Nano-beam option QCSR QCSL QC2L e+ e- γ SVD Beam pipe (Parallel to HER R = 10.5mm ) QC3L B0SM HER beam

28 HER upstream x10 6 Nano-beam option 5σ beam SR (reached to the IP) production position Z-position(cm) SR energy (at IP) 5 kev 50 kev (Vertical scale: Scaled for 1-bunch beam) Energy(MeV)

29 LER beam-line simulation Nano-beam option e+ e- γ BL1 QC3L LER beam QC2L QC1L QC1R QC2R QC3R BL0

30 LER upstream Nano-beam option 5σ beam SR (reached to the IP) production position Z-position(cm) SR energy (at IP) Nano-beam LER SR energy ~ High-current LER SR 5 kev 50 kev (Vertical scale: Scaled for 1-bunch beam) Energy(MeV)

31 LER beam-line simulation Nano-beam option e+ e- γ QC2R QC1R SVD QC1L QC2L QC3R BL0 Beam pipe (Parallel to LER R = 10.5mm ) LER beam

32 LER upstream x10 6 Nano-beam option 5σ beam SR (reached to the IP) production position Z-position(cm) SR energy (at IP) 3 kev 50 kev (Vertical scale: Scaled for 1-bunch beam) Energy(MeV)

33 E deposit to the beam pipe Nano-beam option Cu+ Au (φ20) Be + Au part L160mm (φ20) 10W LER 5W 30W 80W HER Cu + Au (φ20) 100mm Preliminary E deposit strongly depends on the beam-pipe geometry

34 Detector BG summary We just start Nano-beam option SR simulation - Nano-beam SR energy(her) ~ 1/10 SR energy(high-current) - Nano-beam SR energy(ler) ~ SR energy(high-current) - Need to implement beam-pipe structure: SR produced at bending magnet may be reduced in front of Q-magnets Need to design SR mask - If we place beam-pipe parallel to LER E deposit (to the Be part) ~ 5W - We need further SR BG study 2. We need to start Touschek / beam-gas BG study

35 Back up

36 The BaBar detector

37 KEKB の場合 Condition: Vacuum chambers are separate from QCS cryostats. CDC SVD+IP chamber

38 KEKB の場合 Condition: Vacuum chambers are separate from QCS cryostats. CDC QCS chamber Step 1: Connect the front half of QCSL chamber and QCSR chamber to IP chamber that is already set at the interaction point. (The end flange of QCSR chamber is temporally removed.)

39 KEKB の場合 Condition: Vacuum chambers are separate from QCS cryostats. CDC QCS chamber Step 1: Connect the front half of QCSL chamber and QCSR chamber to IP chamber that is already set at the interaction point. (The end flange of QCSR chamber is temporally removed.)

40 KEKB の場合 Condition: Vacuum chambers are separate from QCS cryostats. QCS cryostat CDC Step 2: Move forward QCS cryostats. Step 3: Connect the end half of QCSL chamber with a magic flange to the front half. Attach the end flange to QCSR chamber.

41 KEKB の場合 Condition: Vacuum chambers are separate from QCS cryostats. CDC Step 2: Move forward QCS cryostats. Step 3: Connect the end half of QCSL chamber with a magic flange to the front half. Attach the end flange to QCSR chamber.

42 High-current option Beam Background SR BG simulation Heating of IR components HOM heating studies (Tohoku / KEK) SR heating calculation (KEK)

43 Relationship between s-belle and Super-KEKB: High current In Super-KEKB, crossing angle will be increased : 22mrad 30mrad e - KEKB / Super-KEKB HER(e - ) axis will not change 8mrad 22mrad HER LER e + KEKB, Belle solenoid Belle solenoid will not change e + Super KEKB LER(e + ) axis will rotate by 8mrad (QCS magnets will be set parallel to Belle solenoid) Beam pipe : parallel to HER

44 IR Layout (High current) H.Koiso (KEK) QC2RE QC2LP QC1RE QCSL (1.9K) QCSR LER beam HER beam QC2LE QC1LE QCSLFE (permanent) QC2RP L-side: New 1.9K quadrupole (QCSL), and Additional horizontal focusing permanent quadrupole (QCSLF) in HER

45 Beam pipe design (High current) LER Be part Au 10µm t Be 2mm t Inner diameter 30mm SR Mask Au Base length 4mm Height 4mm Inner diameter 22mm S.Uno HER 30mrad 30 IP Au straight part Au 5mm t Inner diameter 30mm Length 20mm Au Taper part Au 5mmt 30mrad taper Length 300mm

46 HER beam-line simulation QC2R QC1R Taper High-current option e+ e- γ QCSR SR mask QCSL Beam pipe QC1L QC2L SVD HER beam

47 LER beam-line simulation High-current option QC2L QCSR QCSL LER beam QC2R e+ e- γ

48 HER upstream SR energy 5σ beam High-current option QC1 QC2 100 kev 40 kev Energy(keV) Energy(keV) (Vertical scale: Scaled for 1-bunch beam) The SR energy from HER is very high We don t want the direct hits from HER SR at first

49 SR hit to the beam pipe High-current option x (cm) LER beam LER taper LER IP beam pipe SR mask HER taper HER HER beam SR mask z (cm) z (cm) y (cm) RMS y = 0.5mm RMS y = 1.2mm z (cm) To avoid the SR hits to the detector from HER beam, we must z (cm) 1. Locate the beam pipe parallel to HER (22 mrad from solenoid) 2. Put a 4mm height SR mask at the HER side In this case, we have direct SR hit to IP beam pipe from LER

50 LER SR hit to the IP beam pipe E particle at beam pipe (Au) E particle at beam pipe (Be) High-current option 10 3 E (kev) E (kev) Beam pipe Be 2mm t Au 10µm t E deposit at beam pipe (Au) E deposit at beam pipe (Be) Be Au particles 10 3 Vertical scale: Scaled for 1-bunch (factor ~1000) Eγ >8keV region <10 3 particles / bunch hit the IP beam pipe < 2% occupancy of PXD (Assumption: probability to go through Au = 1%, #pixel = 2.5M, integration time = 10µs) For further study, we need more statistics

51 E deposit from upstream SR High-current option E (GeV) HER SR mask HER taper HER beam E (GeV) LER LER taper SR mask LER beam Beam tail cut : 5σ z (cm) Total E deposit to the IP beam pipe SR Mask 100W HER taper 60W LER taper 97W Be part 17W

52 E deposit from SR Total E deposit to the IP beam pipe SR Mask 100W HER taper 60W LER taper 97W Be part 17W 100W energy deposit to the SR mask (x10 of KEKB) Thermal calculation by H.Yamaoka-san (KEK) Max. temp. vs. Cooling ability. High-current option Max. 87 In case of 3000W/m 2 C, 25degC; - The max. temperature ~87degC - Other SR hit positions are around 5-10degC of temperature rise.

53 Design Options Comparison of parameters KEKB Design β y* (mm)(ler/her) 10/10 KEKB Achieved (): with crab 6.5/5.9 (5.9/5.9) SuperKEKB High-Current Option SuperKEKB Nano-Beam Option 3/6 0.22/0.22 ε x (nm) 18/18 18(15)/24 24/18 1/1 σ y (µm) / /0.044 ξ y /0.056 (0.101/0.096) 0.3/ /0.07 σ z (mm) 4 ~ 7 5(LER)/3(HER) 6 I beam (A) 2.6/ /1.45 (1.62/0.95) 9.4/ /1.70 N bunches 5000 ~ Luminosity (10 34 cm -2 s -1 ) (1.68) High Current Option includes crab crossing and travelling focus. Nano-Beam Option does not include crab waist.

54 Final Q layout High-current option Nano-beam design is not fixed yet Nano-beam option Common QCS for 2 beams Two-separate Q-magnets for each 2 beams QCS QCS HER beam LER beam HER beam LER beam Beam pipe Beam pipe To connect with the separate Q magnets the IP beam pipe has branch structures (crotch structures)

55 Beam BG study (High current) - In Super-KEKB, much higher SR BG is expected Critical energy is 14keV SR size at IP is 3-7mm for 5σ size beam (KEKB : 2keV and <5mm for 10σ size beam) Then we estimate the SR BG first - Other BG sources will be studied later Beam-gas, radiative BhaBha, Touschek, - For the BG studies, we construct the beam-line simulation based GEANT4 developed by K.Tanabe and T.Abe of U.Tokyo Simple beam pipe + 1 st layer SVD + B-field of Q-magnets The number of particles in a bunch (High-current option) HER : 4.1A / (1.6*10-19 )/(100kHz)/5000 = 0.5 *10 11 LER : 9.4A / (1.6*10-19 )/(100kHz)/5000 = 1.2 *10 11