M. Koratzinos Rome 2018 workshop 23//2018

M. Koratzinos Rome 2018 workshop 23//2018
MDI Summary M. Koratzinos Rome 2018 workshop 23//2018 M. Koratzinos, MDI summary, Rome 2018

M. Koratzinos, MDI summary, Rome 2018
What is MDI? Machine – Detector Interface covers the area close to the beam pipe and around the interaction point of each experiment. It includes The beam pipe around the IP Any final focus elements, if inside the detector The detector solenoid compensation scheme Also has to deal with The effects of passing and colliding beam (SR radiation, impedance heating) …Without forgetting important engineering aspects tolerances, mechanical vibration, force management, cryogenics At the same time, MDI elements should not impede detector quality Hermeticity, adequate coverage for the luminometer, etc. Space is at a premium M. Koratzinos, MDI summary, Rome 2018

Why is MDI important? In a modern e+e- collider the MDI is arguably one of the most difficult aspects to design and operate MDI elements should only occupy a very small cone along the beam pipe – we are trying to fit everything to within 100mrad Small beta*_y requires the Final Focus quadrupoles to be inside the detector Very stringent optics requirements necessitate the use of a solenoid compensation scheme Integral longitudinal field seen by the electrons needs to be zero Vertical emittance blow up needs to be within budget (<0.5pm) Any dispersion bumps need to close locally The FF elements need to be at very low longitudinal field (total integral <50mTm) M. Koratzinos, MDI summary, Rome 2018

Example – baseline solution for FCC-ee
L* = 2.2m; 30mrad opening angle between beamlines – elegant solution satisfying all requirements Luminometer needs to fit in front of magnetic elements and as far back as possible to have a decent rate FF quads sit in a zero longitudinal field region (integral of solenoid field <50mTm ) encompassed by a screening solenoid which needs to extend to L* of 2.0m A compensating solenoid must sit between the screening solenoid and luminometer to ensure an integral field of zero Screening solenoid Unlike linear colliders, we are facing the challenge of FF quads inside the detector! Luminometer IP FF quads Compensating solenoid M. Koratzinos, MDI summary, Rome 2018

Zoom at 2.2m from the IP FF quads M. Koratzinos, MDI summary, Rome 2018

The MDI session today M. Koratzinos, MDI summary, Rome 2018

Yasushi Arimoto: experience from superKEKb
M. Koratzinos, MDI summary, Rome 2018

A parenthesis For FCC-ee (and CEPC) the energy of the two beams is strongly coupled and equal For FCC-ee, the baseline FF quadrupole design using the CCT concept cancel coils are incorporated in the design of the FF quadrupole M. Koratzinos, MDI summary, Rome 2018

Note that first FF quad sits in high magnetic field M. Koratzinos, MDI summary, Rome 2018

Measurement campaign M. Koratzinos, MDI summary, Rome 2018

To measure magnetic centers of quads M. Koratzinos, MDI summary, Rome 2018

55 magnets! M. Koratzinos, MDI summary, Rome 2018

Overview of MDI for CEPC from accelerator side
Sha Bai, Chenghui Yu, Yiwei Wang, Yuan Zhang, Dou Wang, Mike Sullivan, Huiping Geng, Na Wang, Yingshun Zhu, Jianli Wang Workshop on the Circular Electron-Positron Collider Università degli Studi Roma Tre

MDI layout and IR design IR superconducting magnets
Outline MDI layout and IR design IR superconducting magnets Solenoid compensation Synchrotron radiation and mask design Beam loss background and collimator design Mechanics and assembly Summary 2

MDI layout and IR design
With Detector solenoid Without Detector solenoid ~cryostat in detail 120mrad The accelerator components inside the detector without shielding are within a conical space with an opening angle of cosθ=0.993. The e+e- beams collide at the IP with a horizontal angle of 33mrad and the final focusing length is 2.2m Lumical will be installed in longitudinal 0.95~1.11m, with inner radius 28.5mm and outer radius 100mm. The Machine Detector Interface (MDI) of CEPC double ring scheme is about 7m long from the IP The CEPC detector superconducting solenoid with 3T magnetic field and the length of 7.6m. 3

IR Superconducting magnets Superconducting QD coils
Two layers of shield coil are introduced outside the QD coil to improve the field quality. The conductor for the shield coil is round NbTi wire with diameter of 0.5mm. There are 44 turns in each pole with different length to optimize the field harmonics along the QD coil. *10-4 Integral field harmonics with shield coils（×10-4） n mm 2 10000 3 4 5 6 7 8 9 -1.70E-03 10 7

IR Superconducting magnets Specification of QD0 and QF1
Magnet name QD0 Field gradient (T/m) 136 Magnetic length (m) 2.0 Coil turns per pole 21 Excitation current (A） 2400 Shield coil turns per pole 44 Shield coil current (A） 126 Coil layers 2 Conductor size (mm) Rutherford NbTi-Cu Cable, width 3 mm, mid thickness 0.95 mm, keystone angle 1.6 deg Stored energy (KJ) 19.0 Inductance (H） 0.007 Peak field in coil (T) 3.2 Coil inner diameter (mm) 40 Coil outer diameter (mm) 53 X direction Lorentz force/octant (kN) 54 Y direction Lorentz force/octant (kN) -112 Magnet name QF1 Field gradient (T/m) 110 Magnetic length (m) 1.48 Coil turns per pole 29 Excitation current (A） 2250 Coil layers 2 Conductor size (mm) Rutherford NbTi-Cu Cable, width 3 mm, mid thickness 0.95 mm, keystone angle 1.6 deg Stored energy (KJ) 30.5 Inductance (H） 0.012 Peak field in coil (T) 3.8 Coil inner diameter (mm) 56 Coil outer diameter (mm) 69 X direction Lorentz force/octant (kN) Y direction Lorentz force/octant (kN) -120 Specification of QD0 and QF1 9

Solenoid compensation
3T & 7.6m Specification of Anti-Solenoid Anti-solenoid Before QD0 Within QD0 After QD0 Central field（T） 7.2 2.8 1.8 Magnetic length（m） 1.1 2.0 1.98 Conductor (NbTi-Cu, mm) 2.5×1.5 Coil layers 16 8 4/2 Excitation current（kA） 1.0 Inductance（H） 1.2 Peak field in coil (T) 7.7 3.0 1.9 Number of sections 4 11 7 Solenoid coil inner diameter (mm) 120 Solenoid coil outer diameter (mm) 390 Total Lorentz force Fz (kN) -75 -13 88 Cryostat diameter (mm) 500 22 anti-Solenoid sections with different inner coil diameters Bzds within 0~2.12m. Bz < 300Gauss away from 2.12m with local cancellation structure The skew quadrupole coils are designed to make fine tuning of Bz over the QF&QD region instead of the mechanical rotation. 10

Solenoid compensation
Emittance growth caused by the fringe field of solenoids Design emitY/emitX expected contribution real contribution H: 3.6pm/1.21nm (0.3%) pm pm (0.01%) W: 1.6pm/0.54nm (0.3%) pm pm (0.09%) Z: 1.0pm/0.17nm (0.5%) pm pm (1.7%) 11

Mask design of IR 3 mask tips are added to shadow the beam pipe wall from 0.7 m to 3.93 m reduces the number of photons that hit the Be beam pipe from 2104 to about 200 (100 times lower). photon trajectories from the mask tips that can still hit the central beam pipe The number of scattered photons that can hit the central beam pipe is greatly reduced to only those photons which forward scatter through the mask tips. The optimization of the mask tips (position, geometry and material) is presently under study. 14

SR from Final doublet quadrupoles
The total SR power generated by the QD magnet is 639W in horizontal and 166W in vertical. The critical energy of photons are about 1.3 MeV and 397keV in horizontal and vertical. The total SR power generated by the QF1 magnet is 1567W in horizontal and 42W in vertical. The critical energies of photons are about 1.6MeV and 225keV in horizontal and vertical. No SR photons within 10 σ 𝑥 directly hitting or once-scattering to the detector beam pipe. Collimators for the beam loss will cut beam to 13 σ 𝑥 . SR photons generated from 10 σ 𝑥 to 13 σ 𝑥 will hit downstream of the IR beam pipe, and the once-scattering photons will not go into the detector beam pipe but goes to even far away from the IP region. SR photons from final doublet quadrupoles will not damage the detector components and cause background to experiments. 15

Beam loss Backgrounds at CEPC
Beamstrahlung Beam-Thermal photon scattering IP1 IP3 242 bunches Revolution frequency: 2997Hz 𝟏.𝟓× 𝟏𝟎 𝟏𝟏 particles/Bunch L: 𝟑× 𝟏𝟎 𝟑𝟒 𝒄𝒎 −𝟐 𝒔 −𝟏 Beam Lost Particles Energy Loss > 1.5% (energy acceptance) Radiative Bhabha scattering Beam-Gas Scattering 16

Collimator design in ARC for Higgs
Beam stay clear region: 18 x+3mm, 22 y+3mm Impedance requirement: slope angle of collimator < 0.1 To shield big energy spread particles, phase between pair collimators: /2+n* Collimator design in large dispersion region: = εβ+ 𝐷𝑥𝑒 2 name Position Distance to IP/m Beta function/m Horizontal Dispersion/m Phase BSC/2/m Range of half width allowed/mm APTX1 D1I.1897 113.83 0.24 356.87 2.2~9.68 APTX2 D1I.1894 356.62 APTX3 D1O.10 6.65 APTX4 D1O.14 6.90 20

Collimator design in ARC for Z
Beam stay clear region: 18 x+3mm, 22 y+3mm Impedance requirement: slope angle of collimator < 0.1 To shield big energy spread particles, phase between pair collimators: /2+n* Collimator design in large dispersion region: = εβ+ 𝐷𝑥𝑒 2 name Position Distance to IP/m Beta function/m Horizontal Dispersion/m Phase BSC/2/m Range of half width allowed/mm APTX1 D1I.1897 113.83 0.24 357.36 0.83~3.23 APTX2 D1I.1894 357.11 APTX3 D1O.10 6.876 APTX4 D1O.14 7.126 Although Z lattice is the same as the one in higgs, the emittance is about 7 times lower. So BSC is smaller. According to the off-momentum dynamic aperture after optimizing the CEPC lattice, and considering the beam-beam effect and errors, the energy acceptance is about 1.0%. 25

3, SC Magnet and Vacuum chamber (remotely)
Assembly nearby the IP 1, IP Chamber (supporting) 3, SC Magnet and Vacuum chamber (remotely) 4, Move Lumical back and attach to the cover of cryostat by alignment holes (remotely) 2, Bellows and Lumical (remotely) (supporting system) 29

Assembly nearby the IP We are studying the special installation tools for the remote connection of bellows. 30

Assembly nearby the IP If the space is large enough, Lumical will be connected together with the SC magnet. The boundary between accelerator and detector is still not clear. The design of HOM absorber and the special tool can’t be confirmed in short period. 31

Assembly nearby the IP Crotch region Helicoflex 32

Summary The finalization of the beam parameters and the specification of special magnets have been finished. The parameters are all reasonable. The detector solenoid field effect to the beam can be compensated. HOM of IR beam pipe has been simulated and water cooling was considered. Beam lifetime of CEPC double ring scheme is evaluated. The most importance beam loss background is radiative Bhabha scattering and beamstrahlung for the Higgs factory. Collimators are designed in the ARC which is about 2km far from the IP to avoid other backgrounds generation. Beam loss have disappeared in the upstream of IP for both Higgs and Z factory. Preliminary procedures for the installation of IP elements are studying. The boundary between detector and accelerator is still not clear. Very long time is needed to confirm the final scheme. 33

Detector Solenoid Compensation Scheme at FCC-ee
Sergey Sinyatkin A.Bogomyagkov, A.Krasnov, E.Levichev, S.Pivovarov BINP Workshop on the Circular Electron-Positron Collider 24-26 May 2018

Baseline IR design Hollow thin wall cryostat Dimensions by Mike Bellow
Can we do better? Dimensions by Mike Bellow Remote vacuum connection Screening solenoid Compensating solenoid BPM No space for the cryostat 100 mrad IP How to transmit mechanical force to the RVC?

Redistribution of main and compensating solenoids lengths (1)
Systematic study of different layouts Geom. length: 1 – L_comp = 0.5 m 2 – L_comp = 0.6 m 3 – L_comp = 0.7 m 4 – L_comp = 0.8 m 5 – L_comp = 0.9 m 6 – L_comp = 1 m B_comp_max ~1/L_comp Cylindrical compensating solenoid Bx ~ (L_total_h-L_comp)2/L_comp

Redistribution of main and compensating solenoids lengths (1)
Conditions: B_sol*L_main+2*B_comp*L_comp=0 L_tot=L_main+2*L_comp=const=4.4 m (geometric length) I5,y ~ hy5 ~ Bx5 Cylindrical compensating solenoid

New design of the cryostat tip (6)
For current design of IR there are several ways to reduce blow-up of vertical emittance: to reduce the main solenoid field. to change the placement of first defocusing lens. to increase the opening angle of detector from ±100 mrad to ±140 mrad. There are more complicated schemes of solenoidal field compensation with additional correction coils to optimize magnetic field of solenoid edges: Cylindrical compensating solenoid for both beams. Individual cylindrical compensating solenoid for each beam. Elliptical compensating solenoid for both beams.

New design of the cryostat tip (6)
3D views 3D views II Top view 1190 mm Screening Solenoid IP Compinsating Solenoid QC1 Lumical Remote Flange HOM abs. Cryostat 270 mm BPM Bellows End of screening solenoid (4 m from the IP). See the talk by S.Pivovarov

Compensating solenoid -Individual cylindrical for each beam (1)
Screening solenoids IP Compensating solenoids Dipole & Skew corrections

Compensating solenoid
-Cylindrical for a both beams (2) -Elliptical for a both beams (3) Screening solenoids Compensating solenoids Dipole & Skew quad corrections

Distribution of magnetic field components along reference trajectory
1 - Individual cylindrical solenoid for each beam 2 - Cylindrical solenoid for a both beams 3 - Elliptical solenoid for a both beams After correction Before correction

Blow-up of vertical emittance (after correction by dipole and skew quads correctors)
1 - Individual cylindrical solenoid for each beam 2 - Cylindrical solenoid for both beams 3 - Elliptical solenoid for both beams After correction of horizontal magnetic field and betatron coupling by dipole and skew quad coils of compensating solenoids. Vertical emittance (2IPs): Em_y < pm*rad

Parameters of solenoids and correctors
Parameters of solenoids and correctors Elliptical compensating solenoid Type L, m h, mm Nw Jmax, A/mm^2 Screening solenoid 2.3 4 9200 480 Compensaiting solenoid 0.4 12 4800 508 Dipole&skew corector 1 0.38 3 54 428 Dipole&skew corector 2 0.17 36 509

Twiss function and eigen oscillation modes after correction
Elliptical compensating solenoid deg deg

Summary New MDI design allows almost totally correct the emittance blow up due to the horizontal field at the orbit and local betatron coupling (y <0.014 pm). It provides space to accommodate necessary accelerator components and 100 mrad lost detector angle necessary for effective registration. Individual corrector coils can be used for hor/vert beam tuning at the IP. Nonlinear correction coils can be wound at these correctors.

Hongbo Zhu (IHEP, Beijing) On behalf of the CEPC Study Group
Radiation Backgrounds for Future High Energy Electron Positron Colliders Hongbo Zhu (IHEP, Beijing) On behalf of the CEPC Study Group Workshop on the Circular Electron Positron Collider – EU edition, 24 – 26 May, Rome

Radiation Backgrounds
Important inputs in to detector (+machine) designs, e.g. detector occupancy, radiation tolerance … Have investigated the most important sources of radiation backgrounds, including Pair production Beam lost/off-energy particles Synchrotron radiation … Extending into other less critical sources 24-26 May 2018 Radiation Backgrounds, H. Zhu

Radiation Backgrounds, H. Zhu
Pair Production Estimated as the most important background at Linear Colliders, not an issue for lower energy/luminosity machines Charged particles attracted by the opposite beam emit photons (beamstrahlung), followed by electron-positron pair production (dominate contributions from the incoherent pair production) Most electrons/positrons are produced with low energies and in the very forward region, and can be confined within the beam pipe with a strong detector solenoid; However, a non-negligible amount of particles can hit the detector → radiation backgrounds Hadronic backgrounds much less critical Guineapig simulation: thank you, linear colliders! 24-26 May 2018 Radiation Backgrounds, H. Zhu

Radiation Background Levels
S. Bai, W. Xu and X. Wang Using hit density, total ionizing dose (TID) and non-ionizing energy loss (NIEL) to quantify the radiation background levels Adopted the calculation method used for the ATLAS background estimation (ATL-GEN ), safety factor of ×10 applied 24-26 May 2018 Radiation Backgrounds, H. Zhu

Higgs, W and Z NIEL per year Hit density, TID and NIEL at the 1st VXD layer (r = 1.6 cm) for operation at different energies Bunch spacing: 680 (H)/210 (W)/25 (Z) ns Hit density (per bunch crossing) TID per year 2 hits per bunch crossing 24-26 May 2018 Radiation Backgrounds, H. Zhu

Effectiveness of Collimators
Suppression of detector backgrounds, close to a factor of 100 in reduction → remaining backgrounds smaller than that from pair production and there is room for further tuning Two collimator designs 24-26 May 2018 Radiation Backgrounds, H. Zhu

Synchrotron Radiation
K. Li & M. Sullivan (SLAC) Beam particles bent by magnets (last bending dipole, focusing quadrupoles) emit SR photons → important at circular machines BDSim to transport beam (core + halo) from the last dipole to the interaction region and record the particles hitting the central beryllium beam pipe Large amount of photons scattered by the beam pipe surface between [1, 2 m] into the central region Collimators made with high-Z material must be introduced to block those SR photons. 24-26 May 2018 Radiation Backgrounds, H. Zhu

Mask Tips 24-26 May 2018 Radiation Backgrounds, H. Zhu

With Collimation Three masks at 1.51, 1.93 and 4.2 m along the beam pipe to the IP to block SR photons → shielding to the central beam pipe Number of photons per bunch hitting the central beam pipe dropping from 40, 000 to 80; power deposition reduced considerably 24-26 May 2018 Radiation Backgrounds, H. Zhu

Summary Preliminary interaction region design that requires further optimization Investigated the main radiation backgrounds that are important for detector design (pair production to be re-visited shortly); more sources of backgrounds to be included Hit density: 2.5 hits/cm2 per bunch crossing TID: 1 MRad per year NIEL: 2×1012 1MeV neq/cm2 per year 24-26 May 2018 Radiation Backgrounds, H. Zhu

Challenges for FCC-ee MDI mechanical design
BINP Challenges for FCC-ee MDI mechanical design A.Krasnov, E.Levichev, S.Pivovarov, S.Sinyatkin BINP, Novosibirsk Workshop on the Circular Electron-Positron Collider , 24-26th May 2018, Rome Workshop, May 2018, Rome

FCC-ee IR new design: motivations
BINP There are following problems with the baseline FCC-ee IR design: A cryostat does not fit the detector requirement of 100 mrad lost angle. A space before the cryostat for accelerator components such as beam position monitors, bellows, flanges, etc. can hardly be found. There is no space for remotely controlled flange and hence the procedure of the IR assembling is not clear. Contribution of the compensation solenoid field in the vertical emittance excitation is rather high. Taking above into account we consider an alternative design discussed below. Workshop, May 2018, Rome

3D conceptual design Interaction Region.
BINP QC2.2 QC2.1 QC1.3 QC1.2 QC1.1 Screening sol. Cryostat “walls” thickness. QC1.1 Outer SS wall 10 mm Remote flange 10 mm vacuumn HOM Absorber Thermal shield 3 mm 10 mm vacuum LumiCal Inner wall 6 mm Correct. sol.(4) In total: ~40…45 mm Anti-sol. Cooling Anti sol. Two bellows BPM Connection Be-Cu Workshop, May 2018, Rome Compens. colls

Conceptual design of beam pipe inside cryogenic magnets
Beryllium beam is only close to the IP, where the beam pipe is a single beam pipe Inner stainless steel tube, 0.7 mm thickness with inner Cu coating Gap 0.7 mm with water flow and wire spacers Stainless steel tube 0.7 mm thickness with outer Ag coating Vacuum gap 0.9 mm with Ultem spacers Outer stainless tube, thickness 1 mm, T=4.2K Correction coil If ID=30 mm, the OD is 38 mm Maximum power load on vacuum beam pipe with ID=30mm due to resistivity losses (assuming Cu) and HOM absorption is 50….100 W/m. Therefore the pipe needs an active cooling. Here we are considering multilayer beam pipe with water cooling: Workshop, May 2018, Rome

Design of 3 layers vacuum chamber.
Ultem ball (0.9 mm) Stainless wireless (0.7 mm) Chamber (1 mm) Chambers (0.7 mm) In half a year we plan to produce a prototype of the 3-layers vacuum tube. We plan to test the cooling water capacity with LHe temperature out of the prototype and the heater (imitating the beam) inside the camber. Workshop, May 2018, Rome

BINP Remote flange prototype
P=100…200 bar. Gasket (Al) Rotatable Ring We designed the prototype of remote flange and after the manufacture we will test the flange connection. Workshop, May 2018, Rome

BINP Remote flange prototype
Workshop, May 2018, Rome

Summary We have started a realistic design of the FCC-ee final focus area which, we believe, satisfies all the requirements both from the detector and accelerator sides. We plan to proceed with development and design of the most critical parts including (1) The IR vacuum system, (2) The remotely connecting flange, (3) The anti-solenoid with individual correctors, (4) The first FF quadrupole. Production of the prototypes is highly desirable. Workshop, May 2018, Rome

…A last point M. Koratzinos, MDI summary, Rome 2018

Emittance blow up – 2T or 3T detector field?
Emittance blow-up is a strong function of beam energy ∆ 𝜀 𝑦 ∝ 𝐸 𝑏𝑒𝑎𝑚 3 Going from 45GeV to 80 GeV the problem reduces by a factor 5.6 – becomes negligible Emittance blow-up is a strong function of detector solenoid field ∆ 𝜀 𝑦 ∝ 𝐵 𝑑𝑒𝑡𝑒𝑐𝑡𝑜𝑟 5 Going from 2T to 3T this factor is 7.6 If the emittance blow up from 2 IPs is 0.4pm at 2T, at 3T it is 3pm This emittance will completely dominate the total emittance (budget is 1pm) Luminosity will be reduced by (=1.7) and for the same statistical accuracy one needs to run 1.7 times longer M. Koratzinos, MDI summary, Rome 2018

Conclusions Nice session showing that MDI design for both the CEPC and FCC-ee are coming of age Backgrounds are important, but can be mitigated with the right masks/collimators Still a lot of work to be done, mainly on the magnetic design: Can a elliptical compensating solenoid work? Can the baseline design be implemented? What exactly are the engineering challenges? Accuracy of construction? Force management? Assembly difficulty? Going from 2T to 3T field for the Z running will cost the experiments a factor of 1.7 reduction in statistics – I believe this more than compensates the loss of detector performance due to a reduced solenoid field (O(5%)?) M. Koratzinos, MDI summary, Rome 2018

M. Koratzinos Rome 2018 workshop 23//2018

Similar presentations

Presentation on theme: "M. Koratzinos Rome 2018 workshop 23//2018"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

M. Koratzinos Rome 2018 workshop 23//2018

Similar presentations

Presentation on theme: "M. Koratzinos Rome 2018 workshop 23//2018"— Presentation transcript:

Similar presentations

About project

Feedback