LHC 2009 - 2010 potential luminosity performance

LHCb 2009 - 2010 luminosity performance - rough estimate - 3.5 TeV

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

Month	Comment	Turn around time	Energy [TeV]	Max number bunches	Protons/Bunch	% nom. intensity	Min beta*	Peak Luminosity cm^-2s^-1	Integrated Luminosity
1	Beam commissioning								First collisions
2	Pilot physics, partial squeeze, gentle increase in bunch intensity, availability low	Long	3.5	19	3 x 10¹⁰		6 m	2.5 x 10²⁹	100 - 200 nb^-1
3		5	3.5	19	5 x 10¹⁰		3 m	1.4 x 10³⁰	~ 0.7 pb^-1
4		5	3.5	72	5 x 10¹⁰	2.5	3 m	5.3 x 10³⁰	~2.5 pb^-1
5a	No crossing angle - could at this stage push intensity see 5b	5	3.5	72	7 x 10¹⁰	3.4	3 m	1 x 10³¹	~5 pb^-1
5b	No crossing angle - squeezing to beta* = 1m at this stage would double these lumi numbers (and the pile-up)	5	3.5	72	10 x 10¹⁰	4.8	3 m	2.1 x 10³¹	~10 pb^-1
6	Possible shift to higher energy - would anticipate ~4 weeks to reestablish physics follow by a fairly gentle increase back up in intensity.	Would aim to first provide a period of physics at the higher energy (4.5 TeV, say ) without crossing angle, this could be followed by a move to 50 ns with a limited number of bunches. Note that the total intensity limit will go down with the move to higher energy.
7	4 - 5 TeV (5 TeV luminosity quoted - doesn't make too much difference). No crossing angle.	5	4 -5	72	7 x 10¹⁰	3.4	4 m	1.1 x 10³¹	~6 pb^-1
8	50 ns - nominal crossing angle - aperture restricts squeezing further - note limited complement of bunches.	5	4 -5	138	7 x 10¹⁰	3.1	4 m	2.2 x 10³¹	~10 pb^-1
9	50 ns	5	4 -5	276	7 x 10¹⁰	6.2	4 m	4.2 x 10³¹	~20 pb^-1
10	50 ns*	5	4 -5	414	7 x 10¹⁰	9.4	4 m	6.5 x 10³¹	~31 pb^-1
(11)	50 ns*	5	4 -5	414	9 x 10¹⁰	11.5*	4 m	1 x 10³²	~50 pb^-1

Assuming:

8 hour fill length throughout - it could be longer, but given the possibility of lost fills, system un-reliability etc. 8 hours is probably optimistic.
20 hours luminosity lifetime - with the intensity above it should be longer but given vacuum, the learning process etc. it won't be optimum.
27 day months. Availability gives time available for physics including turn-arounds. Rest of time in machine development, access, recovery etc. 3 days per month out for technical stop
300 microrad crossing angle with 50 ns.
Squeeze to 4m.
Above numbers give a Hubner factor ~ 0.2 - could be considered optimistic

Number of bunches, crossing angle and minimum beta* following Werner Herr at Chamonix 2009

ML September 09