1. MEIC New Baseline: Luminosity Performance and Upgrade Path

2. New MEIC Baseline New major components: Energy range: Design points:
Electron collider ring: PEP-II magnet
Ion collider ring: super-ferric magnet
Ring circumference: ~2200 km
Single booster ring: 285 MeV to 8 GeV
Electron ring RF: PEP-II, 476 MHz (to be decided)
Energy range:
Electron: to 12 GeV
Proton: (8) 20 to 100 GeV
Lead ions: ? to 40 GeV
Design points:
Low energy: GeV x 4 GeV (space charge dominated)
Medium energy: GeV x 6 GeV (beam-beam dominated)
High energy: GeV x 8 GeV (synchrotron radiation dominated)
(another set? (20x3), 50x5, 100x5, 100x10, proton
50x5 deuterium, 67x10 He3, 40x5 Pb, 40x10 Pb )

3. Low Energy (Ecm~21.9 GeV) Point Parameters
Detector type
Full acceptance
Large Acceptance
Proton
Electron
Beam energy
GeV 30 4
Collision frequency
MHz
750
Particles per bunch
1010
0.37
2.5
Beam Current A
0.44 3
Polarization %
> 70
~ 80
RMS bunch length cm
1.2
emittance, normalized
µm rad
0.35 / 0.12
74 / 24.7
Horizontal and vertical β*
6 / 2
6.9 / 2.3
4 / 0.8
2.8 / 0.93
Spot size at IP, horiz. and vert. µm
25.6 / 8.5
16.2 / 5.4
Vertical beam-beam tune shift
0.013
0.017
Laslett tune shift
0.06
Very small
Distance from IP to 1st FF quad m 7
3.5
4.5
Hour-glass effect
0.77
0.51
Luminosity per IP, 1033
cm-2s-1
1.9
3.1
Slide 3 3

4. Medium Energy (Ecm~45.2 GeV) Point Parameters
Detector type
Full acceptance
Large Acceptance
Proton
Electron
Beam energy
GeV 85 6
Collision frequency
MHz
750
Particles per bunch
1010
0.42
2.5
Beam Current A
0.5 3
Polarization %
> 70
~ 80
RMS bunch length cm 2
1.2
emittance, normalized
µm rad
0.3 / 0.06
130 / 26
0.35 / 0.06
Horizontal and vertical β*
10 / 2
7.5 / 1.5
6 / 1.2
4 / 0.8
Spot size at IP, horiz. and vert. µm
18.2 / 3.6
28.8 / 5.8
14.2 / 2.8
21 / 4.2
Vertical beam-beam tune shift
0.007
0.03
0.008
0.027
Laslett tune shift
0.028
Very small
Distance from IP to 1st FF quad m 7
3.5
4.5
Hour-glass effect
0.85
0.71
Luminosity per IP, 1033
cm-2s-1
4.6
6.9
Slide 4 4

5. High Energy (Ecm~56.6 GeV) Point Parameters
Detector type
Full acceptance
Large Acceptance
Proton
Electron
Beam energy
GeV
100 8
Collision frequency
MHz
750
Particles per bunch
1010
0.42
1.46
Beam Current A
0.5
1.75
Polarization %
> 70
~ 80
RMS bunch length cm 2
1.2
emittance, normalized
µm rad
0.45 / 0.09
290 / 58
Horizontal and vertical β*
10 / 2
7.5 / 1.5
6 / 1.2
4 / 0.8
Spot size at IP, horiz. and vert. µm
20.6 / 4.1
37.3 / 7.5
15.9 / 3.2
27.2 / 5.4
Vertical beam-beam tune shift
0.002
0.018
Laslett tune shift
0.02
Very small
Distance from IP to 1st FF quad m 7
3.5
4.5
Hour-glass effect
0.85
0.7
Luminosity per IP, 1033
cm-2s-1
1.7
2.6
Slide 5 5

6. Reusing PEPP-II RF: 748 MHz  476 MHZ
Number of bunches in the ring is reduced by 36%
Same current, bunch intensity is increased by 36%
Same current, beam-beam parameter is increased by 36%
To the first order,
In a beam-beam limited parameter regime, the luminosity is decreased by 36%
In a non-beam-beam-limited parameter regime, the luminosity is increased by 36%

7. Low Energy (Ecm~21.9 GeV) Point Parameters @ 476 MHz
Detector type
Full acceptance
Large Acceptance
Proton
Electron
Beam energy
GeV 30 4
Collision frequency
MHz
476
Particles per bunch
1010
0.37
2.8
2.9
Beam Current A
0.28
2.1
2.2
Polarization %
> 70
~ 80
RMS bunch length cm
1.2
emittance, normalized
µm rad
0.35 / 0.12
74 / 24.7
Horizontal and vertical β*
6 / 2
6.9 / 2.3
4 / 0.8
2.8 / 0.93
Spot size at IP, horiz. and vert. µm
25.6 / 8.5
16.2 / 5.4
Vertical beam-beam tune shift
0.015
0.017
Laslett tune shift
0.06
Very small
Distance from IP to 1st FF quad m 7
3.5
4.5
Hour-glass effect
0.77
0.51
Luminosity per IP, 1033
cm-2s-1
1.35
2.3
Slide 7 7

8. Medium Energy (Ecm~45.2 GeV) Point Parameters @ 476 MHz
Detector type
Full acceptance
Large Acceptance
Proton
Electron
Beam energy
GeV 85 6
Collision frequency
MHz
476
Particles per bunch
1010
0.66
3.9
Beam Current A
0.5 3
Polarization %
> 70
~ 80
RMS bunch length cm 2
1.2
emittance, normalized
µm rad
0.3 / 0.06
130 / 26
0.35 / 0.12
74 / 24.7
Horizontal and vertical β*
10 / 2
7.5 / 1.5
6 / 1.2
4 / 0.8
Spot size at IP, horiz. and vert. µm
18.2 / 3.6
28.8 / 5.8
14.2 / 2.8
21 / 4.2
Vertical beam-beam tune shift
0.011
0.047
0.042
Laslett tune shift
0.028
Very small
Distance from IP to 1st FF quad m 7
3.5
4.5
Hour-glass effect
0.85
0.71
Luminosity per IP, 1033
cm-2s-1
7.1
10.8
Slide 8 8

9. High Energy (Ecm~56.6 GeV) Point Parameters @ 476 MHz
Detector type
Full acceptance
Large Acceptance
Proton
Electron
Beam energy
GeV
100 8
Collision frequency
MHz
476
Particles per bunch
1010
0.66
2.3
Beam Current A
0.5
1.75
1.46
Polarization % 70
~ 80
> 70
RMS bunch length cm 2
1.2
emittance, normalized
µm rad
0.45 / 0.09
290 / 58
Horizontal and vertical β*
10 / 2
7.5 / 1.5
6 / 1.2
4 / 0.8
Spot size at IP, horiz. and vert. µm
20.6 / 4.1
37.3 / 7.5
15.9 / 3.2
27.2 / 5.4
Vertical beam-beam tune shift
0.003
0.028
0.004
0.025
Laslett tune shift
0.02
Very small
Distance from IP to 1st FF quad m 7
3.5
4.5
Hour-glass effect
0.85
0.7
Luminosity per IP, 1033
cm-2s-1
2.7
4.0
Slide 9 9

10. Consideration of MEIC Upgrade Path
Present approach
First stage baseline (MEIC) up to 100 GeV x 12 GeV (10 years)
Energy upgrade (EIC) up to 250 GeV x 20 GeV
Alternative approach
First stage baseline (MEIC) up to 100 GeV x 10 GeV (5 years)
Luminosity upgrade (HL-MEIC) same, luminosity x 3~ (5 years)
Energy upgrade (HE-MEIC=EIC) up to 250 GeV x 14(?) GeV
What is the first stage baseline?
Very conservative, all based on “ready-to-build” technologies
Acceptable starting performance
Significant relaxation of the machine design
Minimum technical uncertainty and R&D requirement (weak cooling)
Minimum cost (PEP-II RF station (476 MHz)

11. Consideration of MEIC Upgrade Path
What constitutes a luminosity upgrade? (A factor of 4)
Doubled the bunch repetition rate (476 MHz  952 MHz)
Increase of the beam current
Reduction of beam emittance (better cooling? Better electron lattice?)
Redesign of IR (beta-star reduction by a factor 2?), including DA
Unmatched beam size?
More aggressive hour-glass effect?
A little large beam-beam?
Space charge compensation? Electron lens?
Small cost (a fraction of energy upgrade cost)

12. Low Energy (Ecm~21.9GeV) Parameters
Detector type: full acceptance
Phase 1
Luminosity upgrade
Proton
Electron
Beam energy
GeV 30 4
Collision frequency
MHz
476
952
Particles per bunch
1010
0.26
3.9
0.43
2.9
Beam Current A
0.2 3
0.65
4.5
Polarization %
> 70
~ 80 70
RMS bunch length cm 2
1.2
emittance, normalized
µm rad
0.6 / 0.2
74 / 24.7
0.35 / 0.12
Horizontal and vertical β*
6 / 2
12 / 4
4.2 / 1.4
4.8 / 1.6
Spot size at IP, horiz. and vert. µm
33.6 / 11.2
21.4 / 7.2
Vertical beam-beam tune shift
0.012
0.015
0.019
Laslett tune shift
0.05
Very small
0.062
Distance from IP to 1st FF quad m 7
3.5
Hour-glass effect
0.91
0.67
Luminosity per IP, 1033
cm-2s-1
0.95
3.7
Slide 12 12

13. Medium Energy (Ecm~45.2 GeV) Parameter
Detector type: full acceptance
First Stage
Luminosity Upgrade
Proton
Electron
Beam energy
GeV 85 6
Collision frequency
MHz
476
952
Particles per bunch
1010
0.66
2.9
0.79
2.6
Beam Current A
0.5
2.2
1.2 4
Polarization %
> 70
~ 80
RMS bunch length cm 2
emittance, normalized
µm rad
0.5 / 0.1
160 / 32
0.4 / 0.08
130 / 26
Horizontal and vertical β*
18.5 / 3.7
7.5 / 1.5
6 / 1.2
9 / 1.8
Spot size at IP, horiz. and vert. µm
32 / 6.6
20 / 4
25.8 / 5.15
Vertical beam-beam tune shift
0.012
0.015
0.008
0.038
Laslett tune shift
0.026
Very small
0.04
Distance from IP to 1st FF quad m 7
3.5
Hour-glass effect
0.87
0.82
Luminosity per IP, 1033
cm-2s-1
3.1
12.1
~3.9
Slide 13 13

14. High Energy (Ecm~56.6 GeV) Parameter
Detector type: full acceptance
First Stage
Luminosity Upgrade
Proton
Electron
Beam energy
GeV
100 8
Collision frequency
MHz
476
Particles per bunch
1010
0.66
2.3
0.92
Beam Current A
0.5
1.75
0.7
Polarization %
> 70
~ 80
RMS bunch length cm 2
1.2
emittance, normalized
µm rad
0.6 / 0.12
290 / 58
0.3 / 0.06
180 / 36
Horizontal and vertical β*
25 / 5
7.5 / 1.5
6 / 1.2
Spot size at IP, horiz. and vert. µm
37.5 / 7.5
14.5 / 1.5
26.3 / 5.0
Vertical beam-beam tune shift
0.008
0.005
0.062
Laslett tune shift
0.016
Very small
0.04
Distance from IP to 1st FF quad m 7
3.5
Hour-glass effect
0.89
0.81
Luminosity per IP, 1033
cm-2s-1
1.8
7.2 ~4
Slide 14 14