Why is one Beam Falling?

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Why is one Beam Falling?

Post by jmayes » Sat Dec 12, 2009 5:40 pm

I (and others in the chat) have noticed that over the last week one beam or the other always seems to fall. The first weeks of testing both beams always stayed the same, is there something in the setup that is causing this (expected) or are they fighting a problem?

Any Guru's in the know?


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Re: Why is one Beam Falling?

Post by March_Hare » Sat Dec 12, 2009 6:17 pm

Good question, was going to ask this too but you beat me to it. Especially yesterday's and today's Page 1 views showed a much more rapid decay of intensity in one beam.
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Re: Why is one Beam Falling?

Post by Danny252 » Sat Dec 12, 2009 7:27 pm

Best suggestion in IRC is that some fills are just worse than others - and of course, they're always fiddling with buttons and switches to try and make it work better.

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Re: Why is one Beam Falling?

Post by morgad » Sat Dec 12, 2009 8:43 pm

They have tweaked the tuning before the current fill. The beam decay rate now seems similar for both beams. estimated beam lifetime is 10 hours :-)

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Re: Why is one Beam Falling?

Post by daavery » Sat Dec 12, 2009 8:59 pm

The intensities fall because the beams are not perfect, they are being scraped by the collimators. Protons that are out of the center of the beam or off energy are continually being removed by the collimator system. what I find interesting is beam 2 is usually getting proton injections that are about 30% bigger than the beam 1 ones. my guess is the difference between the injection paths makes for the difference.

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Re: Why is one Beam Falling?

Post by seabass » Sun Dec 13, 2009 1:56 am

jmayes wrote: are they fighting a problem?


that would be my guess...

lots of tweaking and such... i really hope that infrastructure can handle all that power :|

they keep letting off on the gas pedal everytime it ramps up to 1.17Tev ... something is turning cherry red in there

kidding :mrgreen:

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Re: Why is one Beam Falling?

Post by cedrich » Tue Dec 22, 2009 8:36 pm

It seems to have been explained in the last status report.

Apparently the tune of beam 2 is near a high order resonance (7th order if I was listening correctly).

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