Where can I see the injection emittance?

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jmc2000
Posts: 153
Joined: Sun May 08, 2011 2:51 pm

Where can I see the injection emittance?

Post by jmc2000 » Tue Jul 26, 2011 11:41 pm

Where can I see the injection emittance for a fill?

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LarryS
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Joined: Fri Dec 04, 2009 3:46 pm
Location: Seymour, CT, USA

Re: Where can I see the injection emittance?

Post by LarryS » Wed Jul 27, 2011 12:50 am

Some “emittance” information is displayed on the “Wire Scan Application” snapshot that is frequently posted in the “Operations Log”. Access to the “Operations Log” requires a CERN Log On Id.

adam_jeff
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Joined: Thu Nov 18, 2010 3:07 pm

Re: Where can I see the injection emittance?

Post by adam_jeff » Wed Jul 27, 2011 8:31 am

You can also work out the emittance from the beam size, if you know the beta (Twiss beta) at the point where the beam size is measured. Beam size = sqrt(beta * emmittance).
On the LHC dashboard, I think that the blue lines on the 'beam size' graph correspond to the BSRT synchrotron-light camera. In this case the beta (measured in metres) would be:

450 GeV BETX BETY
B1 162.5 174.0
B2 130.1 417.6

3500 GeV BETX BETY
B1 173.0 194.8
B2 130.0 371.7

I have no idea what the red lines show, does anyone know?

Kasuha
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Re: Where can I see the injection emittance?

Post by Kasuha » Wed Jul 27, 2011 9:48 am

adam_jeff wrote:I have no idea what the red lines show, does anyone know?
Blue solid = B1 horizontal
Blue dotted = B1 vertical
Red solid = B2 horizontal
Red dotted = B2 vertical

adam_jeff
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Re: Where can I see the injection emittance?

Post by adam_jeff » Wed Jul 27, 2011 12:02 pm

Oh yes, kind of obvious. D'oh!

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