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 Update on JLEIC Electron Ring Design  Update on JLEIC Electron Ring Design

Update on JLEIC Electron Ring Design - PowerPoint Presentation

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Update on JLEIC Electron Ring Design - PPT Presentation

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

000 gev length arc 000 gev length arc long spin angle radius bending fodo physical ring power 1k4c0 beam

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Slide1

Update on JLEIC Electron Ring Design

Fanglei

Lin

Slide2

Update on the design tasks for pre-CDRUpdate on the lattice design in detailPlan

Outline

2

Slide3

Finish 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

Slide4

The 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

Slide5

Arc 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

Slide6

Dispersion 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

Slide7

Chromaticity 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

Slide8

Spin 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

Slide9

Anti-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

Slide10

Upstream 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

Slide11

Downstream 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

Slide12

Downstream 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

-

Slide13

Straight 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

Slide14

Arc 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

Slide15

Complete Electron Ring Optics

15

e

-

IP

Ring circumference

2498.6 m,

arc length 956.2

m,

straight length 293.1 m

Slide16

Electron Ring Footprint

16

310m

1000 m

IP

e

-

Slide17

Electron 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

Slide18

RF

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

Slide19

Emittance

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

Slide20

Aperture 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)

Slide21

Dipoles:Quadrupoles:Sextupoles:

Element Count

21

Slide22

Plan

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

Slide23

23

Back Up

Slide24

BPM

24

NSLSII BPM between quadrupole and sextupole

PEP-II and

SuperB

BPM

Slide25

25

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

Slide26

26

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