Fanglei Lin Update on the design tasks for preCDR Update on the lattice design in detail Plan Outline 2 Finish dynamic aperture study in progress Retune the lattice Reserve enough space for BPMs ID: 776376
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Slide1
Update on JLEIC Electron Ring Design
Fanglei
Lin
Slide2Update on the design tasks for pre-CDRUpdate on the lattice design in detailPlan
Outline
2
Slide3Finish dynamic aperture study (in progress)Retune the lattice:Reserve enough space for BPMs (existing drift-bpm-drift (5+5+7.5)cm space in arc FODO cells should be long enough, based on the experience in PEP-II and SuperB CDR and NSLSII (see more detail in the backup slides))Replace sbend with rbend in arcs (done)Adjust spin rotator dipoles to reduce the linear density of SR powerReserve realistic space for RF cavities (space in straights is long enough)Make space for crab cavities in the arcsRedesign the detector region optics including the compensation of coupling induced by the detector solenoid (done)Integrated latest detector region design with correcting elements (done)Update the nomenclature (in progress)Reduce * (one version has been done for the beam-beam simulation)
Design Tasks for Electron Collider Ring
3
Slide4The new electron ring is designed using new magnets. Comparing to PEP-II magnets,short dipoles in arcs have a better control of emittance and sagitta,quads, except for those in the IP region, are slightly stronger, but still warm magnets,sextupoles, bpms and correctors have same lengths, but strengths are different.The ring circumference is 2498.6 m, with a figure-8 crossing angle of 69. Each arc is 956.2 m long and each straight is 293.1 m long.
General Information
4
e
-
R=155m
Spin rotator
Spin rotator
Arc,
249
69
Forward e
-
detection and polarimetry
IP
Tune trombone & Straight FODOs
Future 2
nd
IP
Spin rotator
Spin rotator
CCB
CCB
CCB
CCB
For illustration only
Slide5Arc FODO Cell
5
Arc FODO cell (each arc has
45
such normal FODO cells)
Length 11.4 m (arc bending radius 155.5 m)
2 dipoles + 2 quadrupoles + 2 sextupoles
108
/108
x/y betatron phase advance
Dipole
Magnetic/physical length 3.6/3.88 m
Bending angle 2.1
, bending radius 98.2 m
0.17 T @ 5 GeV, 0.34 T @ 10 GeV
Sagitta 1.65 cm
Quadrupole
Magnetic/physical length 0.56/0.62 m
Field gradient 8.7 T/m @ 5 GeV, 17.5 T/m @ 10 GeV
0.79T @ 4.5 cm radius @ 10 GeV
Sextupole (for linear chromaticity compensation)
Magnetic/physical length 0.25/0.31 m
325 and -151 T/m
2
field strengths @ 5 GeV, 650 and -302 T/m
2
@ 10 GeV
0.66 and -0.30 T @ 4.5 cm radius @ 10 GeV
BPM and Corrector
Physical length 0.05 and 0.3 m
Slide6Dispersion Suppressor at Ends of FODO Cells
6
Similar to the arc-FODO-cell structure, buttotal bending angle in this two-cell structure is same as the one in one normal FODO cell DipoleMagnetic/physical length 3.6/3.88 mBending angle 1.3 and 0.8, bending radius 159 and 257 m0.1 and 0.06 T @ 5 GeV, 0.2 and 0.12T @ 10 GeVSagitta 1.02 and 0.63 cmQuadrupoleMagnetic/physical length 0.56/0.62 mMaximum field gradient 8.8 T/m @ 5 GeV, 17.6 T/m @ 10 GeV 0.8T @ 4.5 cm radius @ 10 GeVBPM and CorrectorPhysical length 0.05 and 0.3 m
Slide7Chromaticity Compensation Block (CCB)
7
CCB is designed considering minimum emittance contribution,non-interleaved –I pair sextupoles for chromatic correction of FFQsDipoleMagnetic/physical length 3.1941/3.4741 mBending angle 1.05, bending radius 174 m0.1 T @ 5 GeV, 0.2 T @ 10 GeVSagitta 0.73 cmQuadrupoleMagnetic/physical length 0.56/0.62 mField gradient in 1 and 2 regions is less than 7.7 T/m @ 5 GeV,15.4 T/m @10 GeV. Field gradient in 3 region reaches 35 T/m @ 10 GeV (can be further optimized)0.7 and 1.6 T@ 4.5 cm radius @ 10 GeV Two CCBs are reserved in the straight for the 2nd IP, but with low beta functions
1
2
3
Crab cavities
Slide8Spin Rotator
8
Spin rotator is designed to rotate the spin between vertical and longitudinal directions, Composed of dipoles and solenoids, and quadrupoles for optics controlAdopted a DBA-like lattice to minimize emittance contribution and suppress spin resonancesSolenoidMagnetic/physical length 2.5 (5) / 2.6 (5.1) m2.2 and 2.9 T @ 5 GeV, ~ 4 and 7 T @ 10 GeVDipoleMagnetic/physical length 4 (2) / 4.2 (2.2) mBending angle 4.4 (2.2), bending radius 52.1 m (local strong SR linear density )0.32 T @ 5 GeV, 0.64 T @ 10 GeVSagitta 3.8* (0.96) cmQuadrupoleDifferent lengths, a few of quads need to reduce the strength * sagitta at the 4m dipole can be reduced to 0.96 cm by cutting it into two halves
E
Solenoid 1
(2.5 + 2.5 m)
Arc Dipole 1
Solenoid
2
(5 + 5 m)
Arc Dipole 2
Spin Rotation
BDL
Spin Rotation
Spin Rotation
BDL
Spin Rotation
GeV
rad
T·m
rad
rad
T·m
rad
3
π/2
15.7
π/3
0
0
π/6
4.5
π/4
11.8
π/2
π/2
23.6
π/4
6
0.62
12.3
2π/3
1.91
38.2
π/3
9
π/6
15.7
π
2π/3
62.8
π/2
12
0.62
24.6
4π/3
1.91
76.4
2π/3
Slide9Anti-solenoids are 1.2 m long in both up- and downstream of IPThey were 1.2 m long in the upstream and 1.6 m long in the downstream in v1 version All FFQs have 60 cm long magnetic length, but different strengthsUse FFQs with skew components for coupling compensation of detector solenoidRemoved all skew quadrupoles v1 versionMove chicane further down by 2.36 m (comparing to that in v1 version) Each side of each magnet (except detector solenoid and anti-solenoids) reserves 10 cm space for coil shaping, coil collars, assembly, etc.Minimum 20 cm for interconnect of magnets for bellows, vacuum pumping, assembly, etc.Each end of each cryostat reserves 30 cm for a warm to cold transition (not all, related to next bullet)Upstream QFFUS2 and QFFUS3 are outside of the ion SB1. But it does not have 30 cm space for a warm to cold transition, but can be solved.
Redesign of Detector Region Optics
9
Slide10Upstream of the IP
10
e
-
2.4 m det. sol. + 0.56m drift
0.6m
1.85 m
0.4m
1.2m
anti. sol.
0.3m
ion SB1
Three 0.6m-long FFQs
At 10 GeV, strengths of FFQs (T/m)
qffus1
= -37.26308053 ;
qffus2
= 42.51112874 ;
qffus3
= -29.39050179 ;
qffus1->
k1s
= 8.170545513 ; (skew)qffus2->k1s = -9.321266714 ; (skew)qffus3->k1s = 6.444352672 ; (skew)
IP: (10,2)cm
Slide11Downstream of the IP (FFQs)
11
1
st
dipole in the chicane
1.6m det. sol.
+ 0.6m drift
0.6m
1.2m
anti. sol.
3.4m
e
-
At 10 GeV, strengths of FFQs (T/m):
qffds1 =
-44.78044481 ;
qffds2 =
43.46563597 ;
qffds3 =
-13.62947228
;
qffds1->k1s = -6.488773242 ; (skew)qffds2->k1s = 6.298254893 ; (skew)qffds3->k1s = -1.974936948 ; (skew)
Three 0.6m-long FFQs
Slide12Downstream of the IP (FFQs + Chicane)
12
Downstream chicane is used for forward low-Q2 detection, suppression of dispersion and compton polarimetry that provides a non-invasive measurement of electron polarization. DipolesDipole 1: 3m-long, bending radius 80m, bending angle 2.15, sagitta 1.4cm.Dipole 2: 0.5m-long, bending radius 200m, bending angle 0.14, sagitta 0.016cm.Dipole 3, 3m-long, bending radius 75m, bending angle 2.29, sagitta 1.5cm.
Forward e
-
detection + C
ompton
polarimetry
e
-
Slide13Straight FODO Cell
13
Straight FODO cell (for space holder and tune trombone, 35 cells in total)Length 12.68 mDrift Maximum 5 m (probably long enough for two RF cavities)QuadrupoleMagnetic/physical length 0.73/0.79 m3.8 T/m @ 5 GeV, 7.6 T/m @ 10 GeVBPM and CorrectorPhysical length 0.05 and 0.3 m
Slide14Arc DS to SBCC / SBCC to Arc DSArc End to Chicane (also used to adjust the phase advance between CCB sextupoles and IP)Upstream FFQ to Tune Trombone (also used to adjust the phase advance between CCB sextupoles and IP)Tune Trombone to Arc EndArc End to Straight FODO CellStraight FODO to Arc End
Matching Sections
14
Slide15Complete Electron Ring Optics
15
e
-
IP
Ring circumference
2498.6 m,
arc length 956.2
m,
straight length 293.1 m
Slide16Electron Ring Footprint
16
310m
1000 m
IP
e
-
Slide17Electron Collider Ring Parameter
17
Beam energy
GeV
5
Circumference
m
2498.64
Straights’ crossing angle
deg
69
Horizontal / vertical beta functions at IP
*
x,y
cm
10 / 2
Maximum horizontal / vertical
beta functions
x,y
max
m
446
Maximum horizontal dispersion
D
x
m
0.497
Horizontal / vertical betatron tunes
x,y
63(.10)/ 61(.81)
Horizontal / vertical natural chromaticities
x,y
-167 / -214
Momentum compaction factor
10
-4
4.6
Transition energy
tr
34.51
Normalized horizontal / vertical emittance
x,y
µm rad
5.63 / 1.13
Horizontal / vertical rms beam size at IP
*
x,y
µm
24 / 4.8
Maximum horizontal / vertical
rms
beam size
x,y
mm
3.2 / 1.5
Slide18RF
18
Electron Ring Operation ParametersEnergy34566.6578910GeVEnergy Loss per Turn0.1130.3590.8751.8152.7393.3635.7379.19014.007MeVSRpower/ring (= power to beam)0.341.082.635.458.229.159.589.589.58MWSR power per unit length0.381.202.936.079.1610.2010.6810.6810.68kW/mEnergy Spread2.77E-043.69E-044.62E-045.54E-046.14E-046.46E-047.39E-048.31E-049.23E-04Trans. SR Damping Time412.13173.8789.0251.5237.8432.4421.7315.2611.13mSecLong. SR Damping Time206.0686.9344.5125.7618.9216.2210.877.635.56mSecBeam Average Current3.0003.0003.0003.0003.0002.7201.6691.0420.684ABunch Length10.010.010.010.010.010.010.010.011.6mmVpeak, Total0.531.272.544.516.257.3611.3316.6819.94MVVgap, 1K2C0.260.320.320.280.240.280.520.690.77 MVVgap, 1K4C0.000.000.000.000.000.000.000.000.00MVGradient, 1K2C0.841.011.010.890.760.901.642.212.44 MV/mGradient, 1K4C0.000.000.000.000.000.000.000.000.00MV/mBucket Heigt / Energy Spread16.7915.8114.8914.0413.5113.2412.5011.828.07Syn. Phase12.416.420.123.826.027.230.433.444.6degreeSyn. Tune0.0100.0130.0160.0200.0220.0230.0260.0300.028Cavity Number, Total248162626222426Klystron Number12481313111213Loading Angle ψL0.00.00.00.00.00.00.00.00.0degreePowerToBeam per Cavity, 1K2C170.19268.93328.29340.37316.07351.83435.35399.07368.37 kWPowerToBeam per Cavity, 1K4C0.000.000.000.000.000.000.000.000.00kWCavity Wall Loss Power, 1K2C9.9514.4814.4211.338.2511.4537.9168.9883.99 kWCavity Wall Loss Power, 1K4C0.000.000.000.000.000.000.000.000.00kWReflected Power, 1K2C16.3333.1868.29125.46177.33135.125.8417.8244.71 kWReflected Power, 1K4C0.000.000.000.000.000.000.000.000.00kWForward Power Per Cavity, 1K2C196.47316.60411.00477.16501.65498.40479.10485.86497.07 kWForward Power Per Cavity, 1K4C0.000.000.000.000.000.000.000.000.00kWTotal RF Power0.3931.2663.2887.63513.04312.95810.54011.66112.924MWRobinson Instability Y, 1K2C1.451.201.201.361.591.220.410.190.11 Robinson Instability Y, 1K4C0.000.000.000.000.000.000.000.000.00Tuning Angle ψ, 1K2C-54.7-49.0-48.4-51.1-55.0-47.4-19.6-9.1-4.6 degreeTuning Angle ψ, 1K4C0.00.00.00.00.00.00.00.00.0degreeδf 1K2C-123.38-100.49-98.52-108.37-124.72-94.98-31.06-13.91-7.05 kHzδf 1K4C0.000.000.000.000.000.000.000.000.00kHzInjection Time with 2 ts24.7313.918.906.185.034.121.930.950.51minLoop Gain of Direct Feedback4.004.004.004.004.004.004.004.004.00
Not
Valid
Will update
Slide19Emittance
19
Beam energy
GeV
3
5
6.9
9
10
Beam current
A
3
3
3
1.1
0.71
Total SR power
MW
0.33
2.51
9.1
9.6
9.5
Energy loss per turn
MeV
0.11
0.84
3.1
8.8
13.4
Energy spread
10
-4
2.8
4.6
6.4
8.3
9.3
Transverse
damping time
ms
462
100
38
17
13
Longitudinal damping time
ms
231
49.8
19.0
8.5
6.3
Normalized Emittance
um
12
54
141
313
429
Slide20Aperture Specifications
20
Detector region electron elements10 GeV/c electrons Element nameTypeLength [m]Good field half-aperture [cm]Inner Half-aperture [cm]Outer Radius [cm]Strength [T or T/m]Skew Strength [T/m]Downstream elements (second focusing point approximately in the middle of chicane)BXSPLrectangular bend [T]31.84.5110.444722484BXSP1rectangular bend [T]31.84.511-0.416930695BXSP2rectangular bend [T]0.51.84.511-0.166782007BXSP2rectangular bend [T]0.51.84.511-0.166782007BXSP1rectangular bend [T]31.84.511-0.416930695BXSPLrectangular bend [T]31.84.5110.444722484AASOLEDSanti-solenoid (T)1.22.24.511-4QFFDS3quadrupole0.62.44.510-13.62947239-1.974936965QFFDS2quadrupole0.62.84.58.543.465636116.298254915QFFDS1quadrupole0.61.74.58-44.78044515-6.488773293SOLDETDSdetector solenoid (T)1.63Upstream elements SOLDETUSdetector solenoid (T)2.43QFFUS1quadrupole0.624.510-37.263080528.170545512QFFUS2quadrupole0.63.24.51142.51112873-9.321266715QFFUS3quadrupole0.61.54.511-29.390501796.444352672AASOLEUSanti-solenoid (T)1.22.24.511-6
10
σ
Large enough to allow the forward e
-
detection
Smooth beam pipe to reduce the impudence
Good enough to apply to all magnets in the ring, considering
(maximum 10
σ
+ 1cm COA +
sagitta
/2)
Slide21Dipoles:Quadrupoles:Sextupoles:
Element Count
21
Slide22Plan
22
Focus on dynamic
aperture study
Tune scan
Misalignment and orbit correction
Multipole effect
Update
the nomenclature
Reduce
*, apply the compensation scheme and study the DA
Slide2323
Back Up
Slide24BPM
24
NSLSII BPM between quadrupole and sextupole
PEP-II and
SuperB
BPM
Slide2525
1
2
5
6
3
4
~32 m
i
e
2. At the ends of each cryostat
30 cm for
C
old bore designs for a warm to cold transition
With a bellows this could be less. Need HOM power loss estimates for bellows.
10 cm for Warm bore designs
Some of this could be inside of the detector area and SB1, depending on design and installation plan
From Mark’s slides on 12/19/17
Slide2626
26
QFFUS1
318.02mm
QSFFUS2
318.02mm
QFFUS2
318.02mm
QSFFUS3
318.02mm
QFFUS3
SB1
631.93mm
132.03mm
731.93mm
531.93mm
132.03mm
From Mark’s slides on 12/12/17