LHC%202010

1
LHC 2010
(Roger Bailey)
1 month pilot commissioning 3 month 3.5 TeV 1
month to go up in energy (maybe) 5 month 5 TeV 1
month ions
2
Initial intensity limits

• Full model (assumes 5e10 max bunch intensity due
  to head-on beam-beam limit)
• Max. 67 x 1013 p
• Only collimation
• Max. 6 x 1013 p (intermediate)
• 15 x 1013 p (tight)

Fix Imax to 6 1013 protons per beam at
3.5TeV (about 20 nominal intensity)
Note 2-3 1013 protons per beam at 5TeV (about 10
nominal intensity)
30MJ stored beam energy
3
Filling schemes

• 50ns scheme, 36 bunches per PS cycle
• 2 SPS injections 72
• 3 SPS injections 108
• 4 SPS injections 144

234 sends 324 bunches to LHC 334 sends 360
bunches to LHC Combinations possible (e.g. 2
334)
4
Luminosity
Thus, to achieve high luminosity, all one has to
do is make (lots of) high population bunches of
low emittance to collide at high frequency at
locations where the beam optics provides as low
values of the amplitude functions as possible.
PDG 2005, chapter 25

• Nearly all the parameters are variable
• Number of particles per bunch ?
• Number of bunches per beam kb
• Relativistic factor (E/m0) ?
• Normalised emittance ?n
• Beta function at the IP ?
• Crossing angle factor F
• Full crossing angle ?c
• Bunch length ?z
• Transverse beam size at the IP ?

5
Performance
Key parameters are ? N kb ? and they are
strongly correlated
Need a crossing angle when kb gt 150
(consequences for aperture)
? Energy not a free choice but has consequences
for F N ?
kb Number of bunches has consequences for F ?
and machine protection
N Bunch intensity has consequences for beam-beam
and pileup
? Has consequences for N F and aperture
Lower energy ? increased beam size ? less
aperture ? higher ?
6
3.5TeV no crossing angle
Energy TeV 0.45 0.45 3.50 3.50 3.50 3.50
Bunch intensity 1.E10 4 4 4 4 4 9
Bunches per beam 2 (1) 12 43 43 156 156
Emittance µm 3.75 3.75 3.75 3.75 3.75 3.75
ß m 11 11 11 2 2 2

Luminosity in 1 and 5 cm-2 s-1 1.7E27 2.0E28 5.5E29 3.0E30 1.1E31 5.5E31
Total inel cross section cm2 6.0E-26 6.0E-26 6.0E-26 6.0E-26 6.0E-26 6.0E-26
Event rate Hz 1.0E02 1.2E03 3.3E04 1.8E05 6.5E05 3.3E06
Event rate / crossing Hz 0.0 0.0 0.1 0.4 0.4 1.9

Protons 8.0E10 1.7E12 1.7E12 1.7E12 6.2E12 1.4E13
nominal 0.0 0.5 0.5 0.5 1.9 4.3
Current mA 0.1 3.1 3.1 3.1 11.2 25.3
Stored energy MJ 0.0 0.1 1.0 1.0 3.5 7.9
Beam size in 1 and 5 um 293.3 293.3 105.2 44.8 44.8 44.8

Monthly integrated (0.2) pb-1 - - 0.29 1.55 5.61 28.38
7
3.5TeV with crossing angle
Energy TeV 3.50 3.50 3.50 3.50 3.50 3.50
Bunch intensity 1.E10 9 7 7 7 7 7
Bunches per beam 156 144 288 432 720 792
Emittance µm 3.75 3.75 3.75 3.75 3.75 3.75
ß m 2 2 2 2 2 2

Luminosity in 1 and 5 cm-2 s-1 5.5E31 3.1E31 6.1E31 9.2E31 1.5E32 1.7E32
Total inel cross section cm2 6.0E-26 6.0E-26 6.0E-26 6.0E-26 6.0E-26 6.0E-26
Event rate Hz 3.3E06 1.8E06 3.7E06 5.5E06 9.2E06 1.0E07
Event rate / crossing Hz 1.9 1.1 1.1 1.1 1.1 1.1

Protons 1.4E13 1.0E13 2.0E13 3.0E13 5.0E13 5.5E13
nominal 4.3 3.1 6.2 9.4 15.6 17.2
Current mA 25.3 18.1 36.3 54.4 90.7 99.8
Stored energy MJ 7.9 5.6 11.3 16.9 28.2 31.0
Beam size in 1 and 5 um 44.8 44.8 44.8 44.8 44.8 44.8

Monthly integrated (0.2) pb-1 28.38 15.85 31.69 47.54 79.23 87.15
8
5TeV
Energy TeV 5.00 5.00 5.00 5.00 5.00 5.00
Bunch intensity 1.E10 4 7 7 7 7 9
Bunches per beam 156 156 144 288 432 432
Emittance µm 3.75 3.75 3.75 3.75 3.75 3.75
ß m 2 2 2 2 2 2

Luminosity in 1 and 5 cm-2 s-1 1.6E31 4.9E31 4.3E31 8.6E31 1.3E32 2.1E32
Total inel cross section cm2 6.0E-26 6.0E-26 6.0E-26 6.0E-26 6.0E-26 6.0E-26
Event rate Hz 9.5E05 2.9E06 2.6E06 5.2E06 7.8E06 1.3E07
Event rate / crossing Hz 0.5 1.6 1.6 1.6 1.6 2.6

Protons 6.2E12 1.1E13 1.0E13 2.0E13 3.0E13 3.9E13
nominal 1.9 3.4 3.1 6.2 9.4 12.0
Current mA 11.2 19.6 18.1 36.3 54.4 70.0
Stored energy MJ 5.0 8.7 8.1 16.1 24.2 31.1
Beam size in 1 and 5 um 37.5 37.5 37.5 37.5 37.5 37.5

Monthly integrated (0.2) pb-1 8.23 25.20 22.39 44.77 67.16 111.02
9
Delivered luminosities

• Without crossing angle
• With crossing angle

Could hit few 1031 cm-2 s-1 say ltLgt of 1031 cm-2
s-1
40 efficiency for physics ? 106 seconds
collisions per month
Integrated luminosity per month 10 pb-1
Could hit few 1032 cm-2 s-1 say ltLgt of 1032 cm-2
s-1
40 efficiency for physics ? 106 seconds
collisions per month
Integrated luminosity per month 100 pb-1
(106 seconds _at_ ltLgt of 1033 cm-2 s-1 ? 1 fb-1)