Beam 2 reduced stability?

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gronos
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Beam 2 reduced stability?

Post by gronos » Tue Apr 06, 2010 1:37 pm

From the last several runs it appears that the luminosity of beam 2 decayed at a faster rate than that for beam 1. This seems the case for several days or weeks now. Does anyone know why beam 2 would appear to lose luminosity faster than beam 1?
Rich Gronostajski
Center of Excellence in Bioinformatics and Life Sciences
University at Buffalo

Kasuha
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Re: Beam 2 reduced stability?

Post by Kasuha » Tue Apr 06, 2010 1:46 pm

It sure is decaying faster but the difference is negligible. The maximum time the beam was circulating was 19 hours and both beams decayed by far less than 5% of their original intensity. When they reach planned beam luminosity, they will decay significantly faster just from collisions.
Don't forget that beams run over different paths - they each have a separate beam pipe and switch left/right position in the four IPs. They are affected by different magnets and so they are not completely equal.

Danny252
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Re: Beam 2 reduced stability?

Post by Danny252 » Tue Apr 06, 2010 1:55 pm

B2 has always been slightly worse than B1 - due to the fact it has a different injection route and path in the LHC, which is apparently (slightly) less well tuned than B1's paths.

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