Ion Collider Ring Design V.S. Morozov for MEIC study group MEIC Collaboration Meeting, JLab October...
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Transcript of Ion Collider Ring Design V.S. Morozov for MEIC study group MEIC Collaboration Meeting, JLab October...
Ion Collider Ring Design
V.S. Morozov for MEIC study group
MEIC Collaboration Meeting, JLab
October 5-7, 2015
22December 18 2014
Page 22MEIC Collaboration Meeting, JLab, October 5-7, 2015 2
Provide the necessary beam parameters' 20(8)-100 GeV protons, 12-40 GeV/u ions' Focusing at the IP that supports luminosities above 1033 cm-2s-1
' Sufficient beam and luminosity lifetime
Capability of operating multiple detectors' One full-acceptance detector incorporated
Small angle detection' Space for a second detector reserved
Polarization preservation and control using figure-8 geometry' Light ion (p, d, 3He, and possibly Li) polarization above 70%' Transverse and longitudinal polarization orientations adjustable at the IP' Sufficient polarization lifetime
Match the electron collider ring geometry' Same tunnel
Incorporate provisions for non-linear dynamics correction' Sextupole families' Chromatic correction scheme
Ion Collider Design Requirements
33December 18 2014
Page 33MEIC Collaboration Meeting, JLab, October 5-7, 2015 3
Figure-8 ring with a circumference of 2153.9 mTwo 261.7 arcs connected by two straights crossing at 81.7
Ion Collider Ring
R = 155.5 m
Arc, 261.7
IPdisp. supp./
geom. match #3disp. supp./
geom. match #1
disp. s
upp./
geom. match
#2disp. supp./
geom. match #3
det. elem.
disp. s
upp.
norm.+SRF
tune
tromb.+
match
beam exp./
match
elec. co
ol.
ions
81.7future 2nd IP
Polarimeter
44December 18 2014
Page 44MEIC Collaboration Meeting, JLab, October 5-7, 2015 4
Ion Collider Ring Parameters
Circumference m 2153.89
Straights’ crossing angle deg 81.7Horizontal / vertical beta functions at IP *
x,y cm 10 / 2Maximum horizontal / vertical beta functions x,y max m ~2500Maximum horizontal dispersion Dx m 3.28Horizontal / vertical betatron tunes x,y 24(.38) / 24(.28)Horizontal / vertical natural chromaticitiesx,y -101 / -112
Momentum compaction factor 6.45 10-3 Transition energy tr 12.46Normalized horizontal / vertical emittance x,y µm rad 0.35 / 0.07Horizontal / vertical rms beam size at IP *
x,y µm ~20 / ~4Maximum horizontal / vertical rms beam size x,y mm 2.8 / 1.3
All design goals achieved
Resulting collider ring parameters
Proton energy range GeV 20(8)-100Polarization % > 70Detector space m -4.6 / +7Luminosity cm-2s-1 > 1033
55December 18 2014
Page 55MEIC Collaboration Meeting, JLab, October 5-7, 2015 5
Basic building block of the arcs' Length of 22.8 m = 1.5 electron FODO cell lengths (26 cells per arc)' Betatron phase advance of 90 in each plane
Dipoles' Magnetic/physical length of 8/8.28 m (implemented as two 4 m long pieces)' Bending angle of 73.3 mrad (4.2), bending radius of 109.1 m, sagitta of 18.3 mm' Field of 3.06 T at 100 GeV/c' x aperture = (4 cm+sagitta/2) = 5 cm, y aperture = 3 cm (10 + 1 cm orbit
allowance)
Quadrupoles' Magnetic/physical length of 0.8/0.9 m' Field gradients of 52.7/-52.9 T/m at 100 GeV/c' Field of 2.1/-2.1 T at 40 mm radius
Sextupole/corrector package next to each quadrupole
' Magnetic/physical length of 0.5/0.6 m' 3 T at 40 mm focusing sextupole adds
34.8/-7.1 units of x/y chromaticity' 3 T at 40 mm defocusing sextupole adds
-3.7/18.1 units of x/y chromaticity
BPM next to each quadrupole' Physical length of 0.15 m
Arc FODO Cell
66December 18 2014
Page 66MEIC Collaboration Meeting, JLab, October 5-7, 2015 6
MEIC Super-Ferric Dipole
2 x 4 long dipole
NbTi cable
3 T
Correction sextupole
Common cryostat
talks by P. McIntyre and A.D. Kovalenko
77December 18 2014
Page 77MEIC Collaboration Meeting, JLab, October 5-7, 2015 7
Provide dispersion suppression and geometric match to the electron ringArc end upstream of IP
' Shaped to provide 50 mrad crossing angle at the IP
Arc end downstream of IP' Shaped to provide 1.5 m separation from the electron beam
Arc Ends
ions IP
20 m
5 m
ions
10 m
2 m
88December 18 2014
Page 88MEIC Collaboration Meeting, JLab, October 5-7, 2015 8
Detector IntegrationFully-integrated detector and interaction region design that meets:
– Detector requirements: full acceptance and high resolution
– Beam dynamics requirements: consistent with non-linear dynamics requirements
– Geometric constraints: matched collider ring footprints
far forwardhadron detectionlow-Q2
electron detection large-apertureelectron quads
small-diameterelectron quads
central detector with endcaps
ion quads
50 mrad beam(crab) crossing angle
n,
ep
p
small anglehadron detection
~60 mrad bend
(from GEANT4)
2 Tm dipole
Endcap Ion quadrupoles
Electron quadrupoles
1 m1 m
IP FP
Roman potsThin exit windows
Fixed trackers
Trackers and “donut” calorimeter
RICH+
TORCH?
dual-solenoid in common cryostat4 m coil
barrel DIRC + TOF
EM
ca
lori
met
er
EM calorimeter
Tracking
EM
ca
lori
met
er
e/π
th
res
ho
ldC
he
ren
ko
v
talks at the Detector & Interaction Region Sessions
concept by P. Nadel-Turonski,R. Ent, and C. Hyde
99December 18 2014
Page 99MEIC Collaboration Meeting, JLab, October 5-7, 2015 9
IR design features' Modular design' Based on triplet Final Focusing Blocks (FFB)' Asymmetric design to satisfy detector requirements and reduce chromaticity' Spectrometer dipoles before and after downstream FFB, second focus downstream of IP' No dispersion at IP, achromatic optics downstream of IP
Ion IR Optics
IP
ions
match/beam expansion FFB FFB
detectorelements
geom. match/disp. suppression
match/beam compression
*,
,
10 / 2 cm
18 / 3.6 μm
x y
x y
1010December 18 2014
Page 1010MEIC Collaboration Meeting, JLab, October 5-7, 2015 10
Space reserved for two 30 m long cooling solenoids in one straight' Solenoids of opposite fields for coupling compensation and polarization dynamics
Electron Cooling Section
ions
cooling solenoid matchcooling solenoidmatch
1111December 18 2014
Page 1111MEIC Collaboration Meeting, JLab, October 5-7, 2015 11
Bunched Beam Electron Cooler
Baseline cooling requirements – Emittance 0.5 to 1 mm-mrad -> reduce IBS effect– Magnetized beam, up to 55 MeV energy, 200 mA current– Linac for acceleration– Must utilize energy-recovery-linac (beam power is 11 MW)
Solution : cooling by a bunched electron beam
ion bunch
electron bunch
Cooling section solenoid
SRF Linacdumpinjector
energy recovery
Electron energy MeV up to 55
Current and bunch charge A / nC 0.2 / 0.42
Bunch repetition MHz 476
Cooling section length m 60
RMS Bunch length cm 3
Electron energy spread 10-4 3
Cooling section solenoid field T 2
Beam radius in solenoid/cathode mm ~1 / 3
Solenoid field at cathode KG 2
talks at the Beam Cooling Sessions
1212December 18 2014
Page 1212MEIC Collaboration Meeting, JLab, October 5-7, 2015 12
Two FODO cells with matching sections for betatron tune control' One of the matching sections shared with electron cooling section
Tune Trombone
ions
match2 FODOmatch
1313December 18 2014
Page 1313MEIC Collaboration Meeting, JLab, October 5-7, 2015 13
Filled with FODOMatching geometry of arc endsRF placed between FODO quadrupoles
Second Straight without IR
ions
matchFODOmatchRF
talk by R. Rimmer
1414December 18 2014
Page 1414MEIC Collaboration Meeting, JLab, October 5-7, 2015 14
Optics of a complete ring with all sections incorporated and matched
Complete Ion Collider Ring Lattice
ions
Arc 1Straight 2
IP
Arc 2Straight 1Arc 1
1515December 18 2014
Page 1515MEIC Collaboration Meeting, JLab, October 5-7, 2015 15
Nonlinear Dynamics: Ion RingExplored multiple compensation schemes –I sextupoles pairs in the arcs
– Compensate chromatic smear at the IP– Compensate residual linear chromaticity with additional sextupoles
-1.5 -1 -0.5 0 0.5 1 1.50
0.2
0.4
0.6
0.8
1
1.2
1.4
x (mm)
y (
mm
)
Dynamic aperture
p/p = 0.0 p/p = 0.1% p/p = 0.2% p/p = 0.3% p/p = 0.4%(- 8p/p , + 13p/p)
At p/p = 0.3%
(- 40x , + 40x)
(- 40y , + 40y)
IP work and talks by Y. Nosochkov and M.-H. Wang of SLAC and G. Wei of JLabwith a lot of help from D. Trbojevic, W. Guo, and Y. Jing of BNL
1616December 18 2014
Page 1616MEIC Collaboration Meeting, JLab, October 5-7, 2015 16
Ion PolarizationFigure-8 design
– Zero spin tune independent of energy: spin precession in one arc is cancelled in the other– Spin control and stabilization with small solenoids or other compact spin rotators
Spin tracking in progress– figure-8 with an error
2 T 2 m control solenoids can stabilize proton and deuteron spins up to 100 GeV
B
B
no stabilization stabilization by 1 solenoid
talk by A.M. Kondratenko
1717December 18 2014
Page 1717MEIC Collaboration Meeting, JLab, October 5-7, 2015 17
Crab CrossingRestores effective head-on collisions with 50 mrad crossing angle
– Luminosity preserved
Deflective crabbing technology (demonstrated at KEK-B)– Transverse electric field of SRF cavities
Local crabbing scheme– One set of cavities upstream of IP next to FFB– Another set of cavities(n+1/2) downstream of IP
IPe-
ions
crab cavities
crab cavities
talks by A. Castilla and J. Delayen
1818December 18 2014
Page 1818MEIC Collaboration Meeting, JLab, October 5-7, 2015 18
Design of the baseline ion collider ring completed
All design requirements met Beam parameters: 20(8)-100 GeV protons, luminosity > 1033 cm-2s-1
One full-acceptance detector integrated, room for a second detector reserved High polarization (>70%) adjustable to any orientation using figure 8 geometry Electron ring geometry matched Non-linear correction scheme developed and provisions for it incorporated into lattice
Ongoing and future work– Design optimization– Non-linear dynamics correction– Error sensitivity studies– Integration of remaining components
• Detector solenoid and compensation• Crab cavities• Vertical doglegs
Current Status & Outlook
1919December 18 2014
Page 1919MEIC Collaboration Meeting, JLab, October 5-7, 2015 19
Backup
2020December 18 2014
Page 2020MEIC Collaboration Meeting, JLab, October 5-7, 2015 20
50 mrad crossing angle' Improved detection, no parasitic collisions, fast beam separation
Forward hadron detection in three stages' Endcap' Small dipole covering angles
up to a few degrees' Far forward,
up to one degree,for particles passing through accelerator quads
Low-Q2 tagger' Small-angle electron detection
Full-Acceptance Detector
R. Ent, C.E. Hyde, P. Nadel-Turonski
2121December 18 2014
Page 2121MEIC Collaboration Meeting, JLab, October 5-7, 2015 21
Detector Region Layout
e-
ions
IP
forward iondetection
forward e-
detection
FFQsFFQs
2222December 18 2014
Page 2222MEIC Collaboration Meeting, JLab, October 5-7, 2015 22
One straight contains an IRThe other straight filled with FODO
Layouts of Two Straights
2323December 18 2014
Page 2323MEIC Collaboration Meeting, JLab, October 5-7, 2015 23
Dipoles: 133' 127 super-ferric, B < 3.06 T' 2 special-design for IR + 4 cos() super-conducting, B < 4.7 T
Quadrupoles: 205' 155 with integrated field < 48 T' 44 with integrated field < 72 T' 6 special-design final-focusing quadrupoles
Sextupoles: 125' Maximum pole-tip field ~1.5 T
Correctors: 197' Each combines x/y kicker, skew quad and higher-order multipoles
BPMs: 197RF: 20 m of normal and 20 m of SC (talk by R. Rimmer)Special elements (talk by L. Harwood)
' Injection kicker' Abort system' Electron cooler solenoids' Spin control elements: short solenoids and dipoles' Polarimeter' Crab cavities' Collimators' Detector solenoid compensating elements
Basic Element Count