Webcast Seminar: The seminar to follow will be webcast as part of - - PowerPoint PPT Presentation

e+e- Factory Overview 11/21/03 D. Rice 1

Webcast Seminar:

The seminar to follow will be webcast as part of the

Accessible Webcast Seminar (AWSem) program initiated at LEPP, Cornell.

The seminar will run from approximately 1:15 PM to 2:30 PM

EST Friday, 21 November, 2003.

Please check

www.lns.cornell.edu/public/COMP/AWSem/index.html for instructions to access the seminar and related links.

If you are connected to participate in the seminar please

either sign into the REAP chat room on the LBNL Secure Messaging server, or send email to dhr@cesr10.lns.cornell.edu

Note that there is a ~20 second delay in broadcasting the

seminar, so be prepared to refer back to a previous slide with your questions.

If all else fails there is a speaker phone in the conference

room at 607 255-3850 for brief comments or help only.

Overview of E+E- …

• r

Highlights of the Workshop on E+E- Factories

(SLAC Oct. 13-16, 2003)

• D. Rice

11/21/2003 www-conf.slac.stanford.edu/icfa03/

e+e- Factory Overview 11/21/03 D. Rice 3

• I. Facilities
• II. AP&Tech Issues

SC coil winding at BNL EC effects Feedback systems IR design BBI & ECI Compensation of PC’s Neg αP optics Strong longitudinal focusing Reliability Injection (trickle charging)

• PEP-II, KEKB
• CESR-c
• BEPC-II
• DAΦNE
• VEPP-2000
• eRHIC

e+e- Factory Overview 11/21/03 D. Rice 4

B Factory Status – PEP-II (M. Sullivan)

Figure from J. Seeman

e+e- Factory Overview 11/21/03 D. Rice 5

e+e- Factory Overview 11/21/03 D. Rice 6

PEP-II records at the end of run 3 (June 2003)

e+e- Factory Overview 11/21/03 D. Rice 7

• J. Seeman, Jun 03

PEP-II Collision Parameters

IP Parameter Design Peak performance (Jun 03) C-M energy (GeV) (e+: 3.1 ; e-: 9.0) 10.58 10.58 Crossing angle (mrad) 0.0 < 1.0 Luminosity (x 1033/cm2/s) 3.00 6.57 Number of bunches 1658 1034 LER current (mA, e+) 2146 1550 HER current (mA, e-) 750 1175 LER/HER current ratio 2.9/1 1.3/1 βy*/βx* (cm/cm) 1.5 / 50 1.2 / 40+, 1.2 / 28- Emittance (nm-rad) (y/x) 1.5 / 49 1.8 / 30+, 1.8 / 49- IP rms beam size σy/σx (µm) 4.7 / 157 4.6 / 113 LER tunes (x/y) 38.64 / 36.57 38.52 / 36.57 HER tunes (x/y) 24.62 / 23.64 24.52 / 23.62 Beam-beam parameter (vertical +/-) 0.03 0.082 / 0.040 Beam-beam parameter (horizontal +/-) 0.03 0.109 / 0.040

e+e- Factory Overview 11/21/03 D. Rice 8

Forward Vertex Bellows – Before Cooling

T_VTX2 Thermocouple ( dT = 105 F = 58 C) Beryllium Vertex Chamber B1 Chamber Hottest Point according to model (300 C)

e+e- Factory Overview 11/21/03 D. Rice 9

VTX Bellows Cooling Installation

e+e- Factory Overview 11/21/03 D. Rice 10

Elliptical Vacuum Valve Failure

• Beam Time Lost 26.00 hours

LER Frangible Link

• Beam Time Lost 47.50 hours

Mystery Pressure Bump Near IP

• Beam Time Lost 15.50 hours

LER Arc 1 Pumping Chamber

• Beam Time Lost 48.50 hours

Q2 Chamber

• Beam Time Lost 50.1 hours

These five incidents contributed 187.6 of the 188.9 hours of downtime attributed to vacuum failures during the 2002-2003 PEP-II run

Vacuum Failures Causing Machine Downtime

e+e- Factory Overview 11/21/03 D. Rice 11

Summer 2003 Hardware Upgrades

♦Fixed the vacuum leak in IR2 septum chamber ♦Fix vacuum problem in LER arc 1 ♦New RF station for HER in region 4 (4-1) ♦Modified all bpms in region 2 to be both x and y ♦Many improvements to RF systems in both rings ♦Added cooling to all LER bellows ♦Added more solenoid windings for LER

e+e- Factory Overview 11/21/03 D. Rice 12

PEP-II Goal for Jul 2004

June 03 Jul 2004 LER energy 3.1 3.1 GeV HER energy 9.0 9.0 GeV LER current 1.45 2.7 A HER current 1.15 1.6 A βy

*

12.0 9.0 mm βx

*

28 28 cm X emittance 50 40 nm-rad Estimated σy

*

4.5 3.4 µm Bunch spacing 1.89 1.26 m Number of bunches 1034 1450 Collision angle head-on head-on mrads Beam pipe radius 2.5 2.5 cm Luminosity 6.5×1033 1.2×1034 cm−2 sec−1

Director’s challenge to deliver another 100 fb-1 by Jul 2004

e+e- Factory Overview 11/21/03 D. Rice 13

♦ We need to further improve the HER and LER beta beats and move closer to the ½ integer in x. ♦ Increase the beam currents and the number of colliding bunches. This means going to a by2 colliding bunch pattern and learning to work with the tune shifts induced by the parasitic crossings. ♦ Understand and control the coupling in the IR ♦ Trickle injection for the LER ♦ Lower the βy* in both rings. We were somewhat successful with this in the HER but the bunch length of the HER is so long that we did not see much (if any) improvement in luminosity. This also means the bunch length will have to be smaller. ♦ Improve injection – better efficiency, less detector background, faster turnaround after a beam abort. If we can get the HER injection backgrounds low enough we will be able to try HER trickle injection. ♦ Minimize the number of beam aborts. Biggest effort is in the RF system. We want to reduce the number of beam aborts to less than one a day.

How do we achieve this?

This is probably overall the hardest

e+e- Factory Overview 11/21/03 D. Rice 14

Advanced B Factory with 952 MHz RF Frequency

• E+ = 8 GeV
• E- = 3.5 GeV

βy

* = 1.5 mm

βx* = 15 cm

• Bunch length = 1.8 mm
• Crossing angle = ~15. mrad
• Beam-beam parameters = 0.15
• N = 6900 bunches
• L = 1.0 x 1036 cm-2s-1
• Site power with linac and campus = ~120 MW.
• I+ = 6.8 A
• I- = 15.5 A

e+e- Factory Overview 11/21/03 D. Rice 15

B Factories – KEKB (Y. Funakoshi)

• Beam energy

– 8GeV (electron) – 3.5GeV (positron) – Operated on Υ(4s)

• Circumference

– ~3018m – Use TRISTAN tunnel

• RF system

– fRF ~ 509MHz – ARES (LER) – ARES+SCC (HER)

• Injector Linac

– Upgraded 2.5GeV -> 8GeV – No Damping rings – 2 bunch injection (e+)

e+e- Factory Overview 11/21/03 D. Rice 16

KEKB IR Design

• Features

– Superconducting Quadrupole magnets – Compensation solenoid – Horizontal crossing angle

• Total crossing angle = 22mrad

– Low-β ฀ βx/βy = 33cm/1cm

e+e- Factory Overview 11/21/03 D. Rice 17

e+e- Factory Overview 11/21/03 D. Rice 18

KEKB Luminosity Records

206.3 /pb /shift 579 /pb /day 12.76 /fb /month 158.7 /fb Total 1.0567

1034/cm2/sec

Lpeak Record value unit

Ldt

∫

Ldt

∫

Ldt

∫

Ldt

∫

: integrated luminosity recorded by Belle Detector

Ldt

∫

e+e- Factory Overview 11/21/03 D. Rice 19

KEKB at 1034

1.057x1034 (1x1034)

/cm2/sec

Peak luminosity 0.065/0.052 (0.039/0.052) 0.096/0.069 (0.039/0.052) Beam-beam parameters ξx/ξy 58/0.7 (33/1) 59/0.58 (33/1)

cm

Beta’s at IP βx/βy 44.512/41.580 (47.52/43.08) 45.507/43.546 (45.52/45.08) Betatron tunes νx/νy

• 0.0207
• 0.0249

Synchrotron tune 7.54 (2)

nsec

Averaged bunch spacing 0.818 (0.22) 1.07 (0.52)

mA

Bunch current 1284 (~5000) Number of bunches 1050 (1100) 1377 (2600)

mA

Total beam current 24 (18) 18 (18)

nm

Horizontal emittance HER LER

( ): design values

e+e- Factory Overview 11/21/03 D. Rice 20

KEKB Luminosity History

e+e- Factory Overview 11/21/03 D. Rice 21

Key Issues for KEKB

• The history of the KEKB commissioning has been

tough fights against three major difficulties.

– Fight against the high beam currents

• Troubles with hardware components
• Instability

– Fight against the single beam blowup due to the electron cloud instability

• Solenoid winding

– Fight against the beam-beam blowup

• Tune survey
• Optics corrections
• Other tuning knobs (X-Y coupling at IP etc.)

e+e- Factory Overview 11/21/03 D. Rice 22

Examples of high current problems

Damaged RF-shield fingers in bellows due to HOM Cu Beam

10 mm

Direct damage by beam hit (Movable Mask)

e+e- Factory Overview 11/21/03 D. Rice 23

High beam currents - Instabilities

• Instability

– Sources

• Fast ion

– Serious with bad vacuum pressure – Can be suppress by bunch-by-bunch FB

• Electron cloud

– Can be suppress by bunch-by-bunch FB

• RF cavity

– Almost no instability due to RF cavities has given beam current limitations. – We need -1 mode damper (with comb-filter) to suppress the instability from the fundamental mode. – We do not need the longitudinal bunch-by-bunch FB.

• Others

– Sometimes broken bellows etc. bring a serious transverse instability. – Some unknown source of impedance brings a strong horizontal instability in HER.

e+e- Factory Overview 11/21/03 D. Rice 24

Solenoid installation (anti-ECI)

400 800 1200 1600 2000 2400 2800 3200

Total length of solenoid

Total length(m) Date

• Sep. 00
• Jan. 01
• Apr. 01
• Sep. 01
• Jan. 02

Bz > 20 G preliminary (very rough estimation) total drift length circumference 1st 2nd 3rd 4th 5th

e+e- Factory Overview 11/21/03 D. Rice 25

Effect of solenoids on vert. beam size

1 2 3 4 5 200 400 600 800 1000 1200 1400 1600 Vertical beam size@IP (micron) LER beam current (mA) 1 train, 1153 bunches, 4 rf bucket spacing

2001 July : on 2001 Dec. : on 2002 Feb. : on 2001 July : off

After last installation of solenoid, blowup was disappeared up to 1300mA. Effect of solenoid in a physics fill pattern (4 rf buckets spacing)

e+e- Factory Overview 11/21/03 D. Rice 26

Suppression of B-B blowup

• Tune survey
• Both Simulations and Surveys in real machine
• Horizontal tunes very close to the half-integer
• Need very fine control of tunes
• Optics correction (global correction)

β functions Dispersion X-Y coupling

• Collision tuning knobs
• Waist points
• X-Y coupling at IP
• Dispersions at IP
• Orbit Feedback around IP

e+e- Factory Overview 11/21/03 D. Rice 27

Optics modeling & correction with SAD – Example – coupling & dispersion at IP

• X-Y coupling and dispersion at IP are

adjusted by using a tuning knob.

• We do not use skew-quads for this

purpose.

• Vertical bumps at 16 sextuples are

used.

• Shift persons & operators frequently

scan X-Y coupling parameters (R1,R2,R3,R4) and η and η’ @IP.

Find of an optimum value for R4 was one of the key points of recent progress in the KEKB luminosity.

e+e- Factory Overview 11/21/03 D. Rice 28

KEKB Upgrade

3 3 10 10

βy

*[mm]

0.1~0.26 0.1~0.26 0.05 0.05

ξy

3 3 5 5

σl [mm]

2~6 x 1035 1 x 1034

L

[/cm2/sec]

4.1 9.4 1.1 2.6

I [A] HER LER HER LER SuperKEKB KEKB (design) ~$30M+ /year 2004-2013

e+e- Factory Overview 11/21/03 D. Rice 29

Path to SuperKEKB

• High beam currents

– Vacuum system – RF system

• Low β

– IR design – Short bunch length

• High beam-beam parameters

– Crab cavity

• Linac upgrade

– C-band RF system

e+e- Factory Overview 11/21/03 D. Rice 30

Vacuum R&D

• Ante-Chamber

– Without photon stops – Test model will be installed in the next shutdown.

• “Finger-less” bellows chamber

A test model was installed in LER. Beam test will be done in the next run.

e+e- Factory Overview 11/21/03 D. Rice 31

Crab cavity development

Crab crossing (+ horizontal tune close to the half-integer) may boost the beam-beam parameter up to 0.2.

crossing angle 22 mrad

Head-on(crab)

◊ ◊ ◊ ◊ ◊

ξy

(Strong-weak simulation) (Strong-strong simulation)

I.R. 20 I.R. 90 I.D. 188 I.D. 120 I.D. 30 I.D. 240 Input Coupler Monitor Port I.R.241.5 483 866 Coaxial Coupler scale (cm) 50 100 150

• > K. Ohmi
• K. Hosoyama, et al

Superconducting crab cavities are under development, will be installed in KEKB in 2005.

e+e- Factory Overview 11/21/03 D. Rice 32

e+e- Factory Overview 11/21/03 D. Rice 33

Charm Factories - BEPC

I II III IV e- RF RF SR e+ IP North

e+e- Factory Overview 11/21/03 D. Rice 34

BEPC-II main parameters

Beam energy range 1–2.1 GeV Optimized beam energy region 1.89GeV Luminosity @ 1.89 GeV 1×10 33 cm-2s-1 Injection from linac Full energy injection: Einj=1.55−1.89GeV Dedicated SR operation 250 mA @ 2.5 GeV

e+e- Factory Overview 11/21/03 D. Rice 35

BEPC-II IR layout – HEP mode

IR lattice consists of SCQ(RED), anti-solenoids(BLUE), ISPB, Q1a,

• Q1b. It has a doublet construction, the separated Q1a and Q1b function

a focusing quadrupole. ISPB make the beams separate further. Anti- solenoids decouple the detector solenoid effects.

e+e- Factory Overview 11/21/03 D. Rice 36

BEPC-II IR layout- SR mode

For SR mode SCB(GREEN) will switch on, the beam will circulate in the outer ring.

e+e- Factory Overview 11/21/03 D. Rice 37

Computer modeling of BBI (Hirata w-s 6D)

Luminosity survey with a crossing angle of φc=11mrad2

e+e- Factory Overview 11/21/03 D. Rice 38

Coupled bunch instabilities

12.8

• Long. (ms)

0.5 3 4.3 26.6

• Tran. (ms)

ECI FBII Resistive HOM

Transverse instability much faster than SR Damping: feedback system required Longitudinal instability same level as SR Damping: feedback system as a backup For SR mode, bunch current and total beam current lower, instabilities weaker than colliding mode.

e+e- Factory Overview 11/21/03 D. Rice 39

Simulations of ECI growth time

0.0058 1.400 1.2×1011 1.066 0.001 Ante+TiN +Clear. 0.015 0.530 3.5×1011 1.066 0.001 ante+TiN 0.81 0.020 1.7×1013 1.066 0.1 TiN only 0.17 0.040 3.1×1012 1.8 0.001 With ante. 2.89 0.003 6.2×1013 1.8 0.1 No ante.

ϒ

τ (ms) EC ρ (m-3) SEY PEY method

With antechamber+TiN: Coupled bunch inst. damped by feedback, no TMCI instability occurs

e+e- Factory Overview 11/21/03 D. Rice 40

BEPC-II time line

• Linac upgrade May-Dec 2004
• Long shutdown April 2005 – January 2006
• Machine commissioning Feb.-Sept. 2006
• Machine-detector tuning Nov. 2006-Feb. 2007
• Physics starts March 2007

e+e- Factory Overview 11/21/03 D. Rice 41

M.E. Biagini, LNF-INFN

• n behalf of the DAΦNE Team

e+e- Factory Overview 11/21/03 D. Rice 42

DAΦNE Rings

KLOE DEAR e+ e- FINUDA C = 97 m E = 0.51 GeV (Φ)

e+e- Factory Overview 11/21/03 D. Rice 43

DAFNE Luminosity

2002 DEAR & KLOE LUMINOSITY

Peak Daily Integrated Total Integrated

e+e- Factory Overview 11/21/03 D. Rice 44

KLOE Runs - 2002

• Background and Lifetime Optimization
• Lowered βx

* (5.6m 2.7m)

• Orbit Optimization
• Old and New Scrapers Optimization
• Sextupoles and Octupoles Optimization
• Improved linear and non-linear knowledge of the machine
• Increased Dynamic aperture (better βs on Sexts and Wigglers)
• Luminosity Optimization
• New Working Point for e- : 0.11/0.15 (Qx/Qy)
• Lowered βy* (3.0cm 2.6cm)
• Lowered βx

* (5.6m 2.7m)

• Decreased horizontal emittance (0.96mm 0.76mm)
• Adiabatic Tuning

e+e- Factory Overview 11/21/03 D. Rice 45

DAΦNE Accel. Physics-

LONGITUDINAL QUADRUPOLE INSTABILITY LONGITUDINAL QUADRUPOLE INSTABILITY

• It appears in both rings,

at high currents but with different single bunch thresholds: ~20% higher for e+

• e+ beam power

spectrum with 100 bunches, 900mA, during collision

• Longitudinal feedback is

able to control the instability

e+e- Factory Overview 11/21/03 D. Rice 46

DAΦNE Hardware activities - 2003

• FINUDA detector & IR Installation
• KLOE new IR installation
• Straight long sections and kickers modifications
• Scrapers modifications
• Bellows modifications
• Ion clearing electrodes modifications
• Wigglers modifications
• Pipe modifications for 3rd RF harmonic cavity

e+e- Factory Overview 11/21/03 D. Rice 47

New Interaction Regions

• New IRs for KLOE and FINUDA have modified optics

(doublet configuration) in order to decrease the IP β functions and lattice chromaticity, optimize background rejection and new supports to provide variable quadrupole rotations, to operate at different detector magnetic fields (from 0 to maximum) 100 bunches operation should be possible in both IRs now

e+e- Factory Overview 11/21/03 D. Rice 48

Bellows Modifications

As found After insertions of pins to straighten the copper bellows

e+e- Factory Overview 11/21/03 D. Rice 49

Wiggler Field Modifications

Sextupole component

Old wiggler: reduction of the dynamic aperture due to:

• Strong sextupole components (~x2 like)
• Field roll off at large offsets (~x6 like)

e+e- Factory Overview 11/21/03 D. Rice 50

Wiggler mods & Dynamic Aperture

Off energy DA before Off energy DA after

e+e- Factory Overview 11/21/03 D. Rice 51

Optics Modifications

• FINUDA & KLOE IR optics are now very similar:
• Lower horizontal emittance: 0.42 µm (0.77)
• Lower β in the wigglers to minimize non linearities
• βx*= 1.7 m (or less if necessary) to allow 100

bunches operation

• βy*= 27 mm, just about equal to the bunch length
• Additional sextupoles in wigglers and at septum
• Phase advance between the sextupoles optimized
• Low beam invariants (H) to minimize background
• Straight sections optimized for injection efficiency

and DA

• Predicted lifetime >3hrs at 2x1030 s.b.

luminosity (with 20mA)

e+e- Factory Overview 11/21/03 D. Rice 52

Performance Goals for KLOE & FINUDA

• 100-110 bunches collisions operation
• 2 A/beam (asymptotically in 2 year)
• 2x1030 single bunch luminosity (at 20 mA, with present WP,

linear extrapolation of obtained results)

• >1h lifetimes (at 2 Amps and 2x1032) (MAD predicts >3h)
• 10pb-1/day, 200pb-1/month, 1.0fb-1/0.5years delivered
• Goals based on extrapolations of 2002 results and the new

low-β IRs. All other upgrades are meant just as safety margins

e+e- Factory Overview 11/21/03 D. Rice 53

DAΦNE beyond 2006

Currently under studies are two options for the future

• f DAΦNE, with major modifications needed:

1) Increase maximum Ecm from 1.4 GeV to >2.2GeV 2) Increase luminosity by >100 w.r.t. 2002-2005 best performances, possibly in the 1034-1035 range A joint Physics & Accelerator Workshop was held in Alghero last September to study the feasibility and the physics case (C.Biscari’s & A. Gallo’s talks)

e+e- Factory Overview 11/21/03 D. Rice 54

Φ Factory – VEPP-2000

ILU 3 MeV Linac B-3M 200 MeV synchro- betatron

BEP

e,e

booster

–+

900 MeV SND CMD-2 ee

– +

→

convertor

2 m 2 m

♦ E ≈ 1 GeV (per beam) ♦ L ≈ 1×1032 cm-2 sec-1 (1×1 bunch)

e+e- Factory Overview 11/21/03 D. Rice 55

Realization of Round Beams

(A.Burov, S.Nagaitsev, Ya.Derbenev, FERMILAB-Pub-01/060-T) Touschek problem for low energy: worse life time!

Conversion of conventional machine using beam adapters

e+e- Factory Overview 11/21/03 D. Rice 56

View of Collider

e+e- Factory Overview 11/21/03 D. Rice 57

VEPP-2000 Lattice

e+e- Factory Overview 11/21/03 D. Rice 58

Weak-Strong BB Simulation

1 2 3 4 5 6 0.05 0.1 0.15 0.2 0.25 Emittance (10-7 m rad) ξ 1 2 strong-strong 0.5 1 1.5 2 2.5 3 0.05 0.1 0.15 0.2 0.25 Emittance (10-7 m rad) ξ 1 2

Emittance of the weak beam vs. the beam-beam parameter. Sextupoles off. Emittance of the weak beam

• vs. the beam-beam para-
• meter. Sextupoles on.

e+e- Factory Overview 11/21/03 D. Rice 59

Strong-Strong BB Simulation

Macroparticles/bunch Np = 50000, transverse mesh 128x128; Field calculated via FFT (K.Ohmi, Phys. Rev. E 59, 7287 (2000)) Comparison of the sextupoles on and off options.

e+e- Factory Overview 11/21/03 D. Rice 60

Main Parameters of VEPP-2000

Parameter Value Circumference 24.38 m RF frequency 172 MHz RF voltage 100 kV RF harmonic 14 Momentum compaction 0.036 Synchrotron tune 0.0035 Energy spread

4

10 4 . 6

−

× Beam emittances (x,y)

7

10 29 . 1

−

× m rad Dimensionless damping decrements (x,y,z)

5

10 19 . 2

−

× ,

5

10 19 . 2

−

× ,

5

10 83 . 4

−

× Betatron tunes 4.05, 2.05 Betatron functions @ IP 10 cm Particles per bunch

11

10 1× Beam-beam parameter (x,y) 0.075, 0.075 Luminosity per IP (at 1GeV)

1 2 32

10 1

− −

× s cm

e+e- Factory Overview 11/21/03 D. Rice 61

2.4 T Dipole Magnet

e+e- Factory Overview 11/21/03 D. Rice 62

Single Mode RF Cavity (172 MHz)

e+e- Factory Overview 11/21/03 D. Rice 63

13.0 T Solenoid

e+e- Factory Overview 11/21/03 D. Rice 64

Linac and Positron Source

debuncher Damping ring To VEPP-2000 electron gun subharmonic

target

linac to VEPP-4 300 MeV linac photo-gun

e+e- Factory Overview 11/21/03 D. Rice 65

Magnet Installation - VEPP-2000

e+e- Factory Overview 11/21/03 D. Rice 66

VEPP-2000 Summary

♠ Start of VEPP-2000 construction – January 2000 ♠ Dipole, quads, sextupoles, skew-quads, steering coils, 6 from 8 vacuum chamber are ready, tested and installed ♠ 13 T field is achieved in solenoid prototype ♠ Weak-strong and strong-strong simulation show high ξ for the round beams ♠ Construction of transfer line from e+ source is going on ♠ Beam → at the end of 2004

e+e- Factory Overview 11/21/03 D. Rice 67

eRIHC (D. Wang)

• New kinematic region
• Ee = 5-10 GeV
• Ep = 30 – 250 GeV
• Sqrt(s) = 20 – 100 GeV
• Kinematic reach of eRHIC

x = 10-4 0.6 Q2 = 0 104 GeV

• High Luminosity

L ~1033 cm-2 sec-1

e+e- Factory Overview 11/21/03 D. Rice 68

eRHIC Design Goals

• Particle species

lepton: e- and e+ hadron: proton, gold ion Au(A=197, Z=79)

• Beam energy

lepton: 5~10 GeV hadron: 25(?)~250 GeV for proton, 100 GeV/n for Au

• Luminosity

e-p collision: 1E32~1E33 cm-2s-1 e-Au collision: 1E30~1E31 cm-2s-1

• Longitudinal Polarization

lepton: e-, 5~10 GeV, e+, 10 GeV, proton: up to 250 GeV

• Particle species

lepton: e- and e+ hadron: proton, gold ion Au(A=197, Z=79)

• Beam energy

lepton: 5~10 GeV hadron: 25(?)~250 GeV for proton, 100 GeV/n for Au

• Luminosity

e-p collision: 1E32~1E33 cm-2s-1 e-Au collision: 1E30~1E31 cm-2s-1

• Longitudinal Polarization

lepton: e-, 5~10 GeV, e+, 10 GeV, proton: up to 250 GeV

e+e- Factory Overview 11/21/03 D. Rice 69

Beam-beam Parameters

Beam-beam parameter assumption in ZDR stage of eRHIC design: 0.005 for hadron beams 0.05 for lepton beams in both planes, for both round and flat beams In lepton In lepton-

• hadron

hadron collider collider, , non-round beam will cause asymmetric horizontal/vertical beambeam parameters. For For hadron hadron beam: beam: if beam is made hori. flat horizontal tune-shift is larger For lapton beam: if it is hori. flat (e_x>>e_y), vertical tune-shift is larger e.g., HERA Beam sizes are matched

) ( 2 ) ( 2

, , , , , , e y e x e y x i y x i e i i y x i y i x i y x e y x e i e e y x

Z N r ZN r σ σ σ β πγ ξ σ σ σ β πγ ξ + = + =

e+e- Factory Overview 11/21/03 D. Rice 70

Main parameters of 10 GeV ring

MW 3.86 5.13 Total radiation power 27.18/21.21 29.13/22.16 Tunes

• 47/-41
• 57/-50

Natural chromaticities cm-2 s-1 2.7E32 1E33 Luminosity 0.025/0.05 0.05/0.05 Beam-beam parameters m 10.65 10.65 Bunch spacing 2.0E-3 1.8E-3 Momentum compaction ms 7.4 7.4 Damping time (long.) kW/m 6.4 9.6 Synchrotron radiation density MeV 11.4 11.4 Energy loss nm.rad 50/12 23/23 Emittance m 0.19/0.19 0.1/0.1 Beta at IP mA 340 450 Total current 6.7E10 1E11 N of particles per bunch GeV 10 10 Beam energy m 1277.9 1277.9 Circumference Flat beam Round beam

e+e- Factory Overview 11/21/03 D. Rice 71

Dynamic Aperture

Very preliminary, trying to get benchmarked with LEGO and SAD

Round beam: not shown here as IR is not fully realistic yet. About ring

• ptics, DA not too bad as thought, even with 400m beta at IR.

SAD(A. Obetov) seems to give better results than MAD. Flat beam: just start, bare lattice, 3(v) and 2(h) sextupole families little tune scan, no local correction, etc.

• n-momentum, seems fine
• ff-momentum, far from optimization, chromatic effects, etc.
• F. Wang

e+e- Factory Overview 11/21/03 D. Rice 72

eRHIC Summary

• Lattice design of e-ring for eRHIC is making significant

progress recently. ZDR is going to be done soon.

• A lot of interesting topics in this high luminosity,

polarized and multi-mode lepton ring design.

• A workable solution with flat beam is found to meet the

basic requirement in IR geometry and SR issue. Likely we can push it further by learning from other factories.

• Spin rotators are embedded in lattice. Polarization looks

promising so far.

• Arc lattice is flexible, DA is yet to be studied in detail.
• For round beam scheme, still long way to go.

e+e- Factory Overview 11/21/03 D. Rice 73

Accelerator Physics & Technology

• Many good talks and discussion on current AP &

tech issues as well as new ideas for future factories.

• Plenary talks:

– B. Parker – BNL direct wind SC IR magnets – G. Stupakov – CSR effects in e+e- storage rings – K. Ohmi –Summary of beam-beam effects – K. Harkay – Observations of ECI – J. Fox – Bunch-by-bunch feedback systems

e+e- Factory Overview 11/21/03 D. Rice 74

AP & Technology (a later talk?)

• Working group topics

– Optics analysis – IR design – BBI simulation – Combined BB & EC effects – Longitudinal instabilities associated with EC – Compensating PC’s with e-m lenses – RF upgrades – SC cavities, harmonic cavities – Collective effects – Operational reliability – Trickle injection in PEP-II – Strong RF focussing – Negative momentum compaction optics

www-conf.slac.stanford.edu/icfa03/

e+e- Factory Overview 11/21/03 D. Rice 75

BBI & EC (F. Zimmermann)

Summary Beam-beam interaction introduces Gaussian variation of betatron tune along the bunch. Simulations show that this addt’l tune variation enhances e-cloud instability. We developed an analytical model, where a bunch consists

• f 3 or 4 particles, electron cloud is represented by constant

wake and by linear tune shift along the bunch, and beam-beam by parabolic tune shift. Model shows that beam-beam tune shift acts destabilizing Agreement between model and simulation seems to improve with increasing number of particles.

e+e- Factory Overview 11/21/03 D. Rice 76

Trickle Charging PEP-II (U. Wienands)

e+e- Factory Overview 11/21/03 D. Rice 77

The one-turn transfer matrix can be put in canonical form:

( )

      − − ⋅ +       ⋅ = ⋅ + ⋅ = +

l l l l

J I L s s M α γ β α µ µ µ µ sin 1 1 cos ˆ sin ˆ cos , with:

( )

L s L s R L s R L s L s R s

c l c c c l c l

α µ µ γ α α µ µ α β α µ µ α 2 sin cos 1 ) ( ) ( 1 ) ( 2 cos 1 1 sin ) ( ) ( 2 1 sin cos 1 ) (

56 56 56

− =               − − − =       − − = Since γl does not depend upon s, the vertical size of the ellipse (i.e. the normalized energy spread σE/E of the equilibrium distribution) does not vary along the ring. The longitudinal emittance εl is related to σE/E according to:

( ) ( )

cos 1 2 sin /

2

L E E

c E l l l E

α µ µ σ ε γ ε σ − = => =

Strong RF Focussing

• A. Gallo
• A. Gallo,

, The Strong RF Focusing: a possible approach to get short bunche

The Strong RF Focusing: a possible approach to get short bunches at the IP s at the IP

e+e- Factory Overview 11/21/03 D. Rice 78

Database of e+e- collider parameters (M. Biagini) is available on the High Luminosity e+e- Collider working group’s web page: http://www.lnf.infn.it/icfa/

End