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Notice the second bucket in each beam does not line up (8941 vrs 8911); this will affect luminosity. There is a deeper reason behind this; it has to do with the asymmetry of the LHCb detector. For details, see http://blog.vixra.org/2010/04/24/lhc-achieves-stable-squeezed-beams/ . Update: there's no...

Today's (24 of april) log have more hump info. The most interesting is this, in the shift summary: Hump active from 7:30 - 9:50 then quite calm. In other words: the hump varies much more wildly than I thought! Looking further in the log, there was another "hump attack" from 17:40 to 18:10. So whatev...

With this fill (the squeezed stable beams of 24 april) they have ten times the luminosity they had before.
That means that this single fill gives about as many collisions as all the previous runs together.

Yes, it would be great to have an idea where it is in the tunnel. I couldn't find anything on that; I am not sure if that means they don't know, or that they just didn't write it down.

By googling around, I found these documents on the hump. You probably need a CERN account, but I am not sure: https://lhc-commissioning.web.cern.ch/lhc-commissioning/meetings/20100112/2010-01-12_LHC_CWG_Q_Stability_revised_CORRECTED.pdf https://lhc-commissioning.web.cern.ch/lhc-commissioning/meeting...

Cool idea! I think you could even get the BPM data directly and listen to it.
I bet with our built-in frequency processor (called "ear") we could easily hear the tunes, and probably hear problems such as the hump. The 11kHz screech might have to be filtered out though; that may be too painful.

Fair enough....Looking at the wave shape.....Typically a slow rise then an abrupt fall. Like a motor starting up then turning off. A vacuum pump? Well, that graph is beam lifetime , instead of "hump intensity" (whatever that may mean). So it is a bit hard to determine the shape of the hump from thi...

If you think matter can be "abused", than hammer manufacturers must be about the worst criminals around!

I found a graph showing the lifetime of the beam, measured one night last week: Lifetime.png Here you can see that if the hump is there, it indeed has a clear cycle that resembles some machine that regulates something. Since this graph shows beam lifetime instead of hump frequency, we cannot deduce ...

We found info on the BKGD information at the OPERATION page: http://op-webtools.web.cern.ch/op-webtools/vistar/vistars.php?usr=LHC3 Basically BKGD stands for "background events", of course. It is expressed in percent. The number signifies how many "false" events there are, as measured by various det...

Thanks Chris for the hint. Here some more enlightening remarks from that shift and the next one: central hump frequency seems to move much faster inside the spectrum since we increased the bunch intensity... (an hour later:) B1 lifetime with 9e10 is about 30h. Lots of hump in the tune spectrum (a fe...

Hi guys,
I found a document on EDMS that explains a lot about the data on the vistar pages (requires external account, you know the drill):
https://edms.cern.ch/file/1026129/2/Exp ... ec-2_5.pdf
Hope this helps in figuring things out together.

I looked at all lines very carefully, especially at the vagueness, and this is my conclusion: Main signal: the .33 line (the very thin one) Second harmonic is .68, which is shown at .18 and its reflection is shown at .32, under the hump. Third harmonic vanishes in the dark blue (would be at 1.01) Fo...

The "intense peak" is the tune: it is supposed to be there. Normally the B1 and B2 tunes are further apart, but this time they are exceptionally close.
The vague moving lines (note time moves upwards) are the hump.

The hump scan they did today gives a lot of new info for wannabee hump hunters. I've been thinking about them, but I can't really figure it out. There's something going on with sum and difference frequencies between the tune and the hump here. Some (but not all) peaks add up to exactly .5; I guess t...