D. Trbojevic, N. Tsoupas, S. Tepikian, B. Parker, E. Pozdeyev, Y. Hao, D. Kayran, J. Beebe-Wang, C. Montag, V. Ptitsyn, and V.

Litvinenko

eRHIC and MeRHIC Lattices and Interaction Regions

eRHIC and MeRHIC Lattice and Interaction Regions

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 2

Recirculation passes in eRHIC designAt present design of eRHIC the beam passes the main linac five times during acceleration. Four of the beam recirculation passes will be placed in the tunnel. Lower energy pass can be put locally.

Possible location of therecirculation passes in the tunnelFour recirculation

passes

PHENIX

STAR

e-ion detector

eRHIC

Main ERL (1.9 GeV)

Low energy recirculation pass

Beam dump

Electronsource

Possible locationsfor additional e-ion detectors

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 3

Previous work on asynchronous lattice (1997)

1997 Particle Accelerator Conference, Vancouver, B.C., Canada, 5/12-16/97, “A Proton Driver for the Muon Collider Source with a Tunable Momentum Compaction Lattice”, D. Trbojevic et. all.

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 4

FMC cell (D. Trbojevic)Dipole filling factor: 54%Reduced lengthTuned to ~0 momentum compaction

For 10GeV:Largest gradient: 7.7 T/mDipole field: 0.16 T

Dipole length: 5.5 mQuad length: 0.6 m

81 m

Basic cell for the arcs

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 5

Separated functions:• R56 tuning: arcs• Phase trombone: straights• Path length tuned: in area of IR insertion (IR12)

One sextant with asynchronous cells

Arc and straights with no IR

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 6

Interaction Straight Layout

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

-100 -50 0 50 100

H-plane V-plane

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

-100 -50 0 50 100

Presently considered geometry of the interaction region straight.Ongoing work on the optics to minimize (or eliminate) dispersion at the IP.

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 7

Second high-Luminosity IR in eRHIC for Q2 detector using just built magnets

from US LARP Magnet Program

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 8

New eRHIC IR designs with b*=5 cmwith the triplet magnets 4.5 m away from the IP.This is for different Q2 physics.

Examining two ways for the chromaticity corrections:1. With zero dispersion at the IP

but non-zero slope of dispersion

2. With zero dispersion and zero slope at the IP.

Quadrupole magnets have gradients of 200 T/m and are 1.6 m, 1 m and 0.85 long.

Second high-Luminosity IR in eRHIC for Q2 detector using just built magnets

from US LARP Magnet Program

0.5 mm

Large aperture, Nb3Sn Quadrupoles for LHC Upgrade

90 mmG > 250 T/m

High PerformanceConductor Development

LengthScale-up

Steve Gourlay

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 9

Assembled LHC triplet

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 10

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 11

RHIC lattice for the present Au-Au run 2010

Dispersion at the IP is zero with non-zero slope. The Dx ~1.5m at the triplets.

Chromaticity correction in RHIC with the IR sextupoles

sextupoles in triplets ON

Chromatic correction in the arcsextupoles strength is reduced

improvedlifetime

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 12

Present RHIC lattice with b*=0.6 m

Chromaticities:xx=-109.39 = (dnx/nx)/(dp/p)xy=-108.23requires correction with 32 A of 100 A maximum for ‘defocusing’ sextupoles, and half for the ‘focusing’ sextupoles

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 13

Methods of correcting the IP chromaticities

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 14

4.5 m

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 15

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 16

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 17

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 18

RHIC lattice with b*=0.05 m

Chromaticities:xx=-109.39 = (dnx/nx)/(dp/p)xy=-108.23requires correction with 32 A of 100 A maximum for ‘defocusing’ sextupoles, and half for the ‘focusing’ sextupoles

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 19

CIRCUMFERENCE = 3833.845 M qX = 6.283185307 RAD nx = 28.8200 xx= -161.81595 RADIUS = 610.1755 M qy = 0.00000000 RAD ny = 26.8100 xy= -165.90281

a =(DS/S)/(DP/P)= 0.0016825 TGAM=( 24.37951, 0.00000)

MAXIMA --- bX ( 1261) = 2184.13229 by ( 1230) = 1733.92123 Dx= 2.92783 MINIMA --- bX ( 1247) = 0.050000 by ( 1247) = 0.050000 Dx= -3.11372

CHROMATICITY AFTER SEXTUPOLE CORRECTIONS xx= 0.00000 xy= 0.0000

AMPLITUDE DEPENDENCE OF TUNES DUE TO SEXTUPOLES nx= 28.820000 + 1630 * ex - 6570 * ey ex ~ ex = 0.2 mm mrad Dnx=0.000326 ny= 26.810000 – 6570 * ex + 3550 * ey

MeRHIC - Lattice and IR

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 20

Lattice design of the MeRHIC:- RHIC modification – Steven Tepikian- Lattice of the Energy recovery linac– Eduard Pozdeyev- Asynchronous arcs and IP – Dmitri Kayran, Dejan Trbojevic- Vertical splitters – Nicholaus Tsoupas- IP and detector protection: J. Beebe-Wang

© J.C.Brutus, J. Tuozzolo, D. Trbojevic, G. Mahler, B. Parker, W. Meng

21Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 21

22

Linacs, spreaders, and an arc

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 22

Magnets: Preliminary Design

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 23

Switchyard at the linac

4GeV

0.1GeV

1.4GeV

2.7GeV0.

2458

m

2.8423 m

1.25 m

0.55 m

0.16

m0.

16 m

1.866 m

0.70

2 m

0.13

6 m

Q4g3

D4g3

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 24

Switchyard at the linac

4GeV

0.1GeV1.4GeV2.7GeV0.

16

1.866 m

Q4g3hb2u hb3

uqu4fqu5

dD4g4uqu3d

qu2f

qu1d

hb4u

hbdu hb1u

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 25

Vertical splitters – Nicholaus Tsoupas

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 26

RHIC lattice modification – Joanne-Beebe Wang

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 27

RHIC lattice modification – Steven Tepikian

b*~0.4 m

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 28

Requirements for the Energy Recovery Linac:• Geometrical constraints: If it is possible use the existing interaction region at RHIC 2

o’clock and wider tunnel to place the superconducting linac inside it. Minimize civil construction cost:

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 29

Zero dispersion IP and detector

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 30

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 31

One Flexible Momentum Compaction Cell:

QF/2QF3

QDQF/2

QD3 QD3

QD

QF3

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 32

Asynchronous arcs: 3.35 GeV Betatron Functions Dmitri Kayran, Dejan Trbojevic

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 33

Asynchronous arcs: 4.00 GeV Dmitri Kayran, Dejan Trbojevic

R=8.88 m

R=12

.3 m

LBL= 1.55 mBy = 1.502397853 Tq = 0.174532925 rad

27.8

9612

mDejan Trbojevic EIC-Stony Brook, January 10-12, 2010 34

Summary:

• Lattice design of the eRHIC and MeRHIC is complete.

• eRHIC:• High Luminosity RHIC lattice – The dynamical

aperture – many turn tracking studies of the RHIC lattice with b*=5 cm are in progress.

• Arc asynchronous lattice with splitters is completed.

• IR designs for large angle IP and high luminosity are in progress.

• Arc magnets samples are already built.

• MeRHIC: • Complete design and layout of the multi-pass

electron and accommodations of the RHIC lattices are completed.

• Preliminary magnet design is completed.• Detail cost estimate of the 4 GeV Medium electron

– ion collider is completed

Dejan Trbojevic EIC-Stony Brook, January 10-12, 2010 35