LHC 2009 - 2010 luminosity performance - estimate  for 3.5 TeV - no move to higher energy

A path to the total integrated luminosity quoted at Chamonix 2009 while keeping the total intensity to a reasonable level. Necessarily approximate. Preliminary.

Step Comment

Turn
around
time

Max number bunches
Protons/Bunch
% nom.
intensity
Min beta*

Peak Luminosity
cm-2s-1

Integrated Luminosity
per month

events/X
1
Beam commissioning
First collisions
2
Pilot physics, partial squeeze, gentle increase in bunch intensity, avaialbility low
Long
43
3 x 1010
4 m
8.6 x 1029
100 - 200 nb-1
3
 
5
43
5 x 1010
4 m
2.4 x 1030
~ 1 pb-1
4
 
5
156
5 x 1010
2.5
2 m
1.7 x 1031
~9 pb-1
5a
No crossing angle - could at this stage push intensity see 5b
5
156
7 x 1010
3.4
2 m
3.4 x 1031
~18 pb-1
0.8
7


No crossing angle.

5
156
7 x 1010
3.4
2 m
4.9 x 1031
~26 pb-1
 
8
50 ns - nominal crossing angle - aperture restricts squeezing further - note limited complement of bunches.
5
144
7 x 1010
3.1
2 m
4.4 x 1031
~23 pb-1
9
50 ns
5
288
7 x 1010
6.2
2 m
8.8 x 1031
~46 pb-1
10
50 ns*
5
432
7 x 1010
9.4
2 m
1.3 x 1032
~69 pb-1
(11)
50 ns*
5
432
9 x 1010
11.5*
2 m
2.1 x 1032
~110 pb-1
   

LHCb equivalent

Assuming:

*  Working with these intensities implies impeccable performance of the machine protection system, and a fully commissioned collimation system capable of highly efficient beam cleaning,. This is going to take time and must not be rushed.

Massi Ferro-Luzzi has made some similar estimates (see for example  http://indico.cern.ch/conferenceDisplay.py?confId=57607  and here) in which he is slightly more optimistic regarding beta* and bunch intensity in the 156 bunch phase. Here we err on the cautious side (1 metre will not necessarily be straightforward, there might be machine protection, injection and ramping issues with higher bunch currents, and there is the issue of pile-up in the experiments (1e11 at 1 metre at 5 TeV buys approx. 7 inelastic per crossing)).

For beam losses, it would be reasonable to take around 10% of the first year figures quoted in "Estimates of Annual Protons Doses in the LHC" where 25 ns running and a peak luminosity of 1033 cm-2s-1 is assumed.

Mike Lamont August 2009