Search found 15 matches

by LHC_Insider
Sun Dec 06, 2009 1:23 am
Forum: The Accelerator
Topic: Weekend of 12-3-09 collision events !
Replies: 188
Views: 22982

Re: *** COLLISION ALERT ***

Beams "debunched" thats interesting.... CMS The history of why we care about debunched beams... Firstly the bunch-train profile of the LHC has a big gap (the abort gap) at the end which allows the dump kickers to ramp up with no particles passing, otherwise it would spray them as the kicker ramped....
by LHC_Insider
Sat Dec 05, 2009 11:54 pm
Forum: The Accelerator
Topic: Weekend of 12-3-09 collision events !
Replies: 188
Views: 22982

Re: *** COLLISION ALERT ***

Different subject... From the CMS Page "gather the experts in preparation for the first physics fills of the LHC." I think its approaching time... Indeedy. We're all awaiting it - which is why I'm up waiting for data to look at, and not tucked up in bed. betcha its gonna be 4x4 Betcha it's not...
by LHC_Insider
Sat Dec 05, 2009 11:39 pm
Forum: The Accelerator
Topic: Weekend of 12-3-09 collision events !
Replies: 188
Views: 22982

Re: *** COLLISION ALERT ***

Xymox wrote:ATLAS has been working hard on this stuff..
And CMS!

I'm always amused by the ATLAS control room; it seems optimally designed to reduce communication between people...
by LHC_Insider
Sat Dec 05, 2009 10:56 pm
Forum: Science
Topic: *** First science results ***
Replies: 9
Views: 3359

Re: *** First science results ***

This presumes there is a Higgs to find. If there is, the time to discovery really depends on the mass of the Higgs. Its mass directly determines what particles it decays to, and that determines how hard it is to see. I.e. in some mass regions it goes to 2 photons (hard), whereas in others it goes to...
by LHC_Insider
Sat Dec 05, 2009 5:50 pm
Forum: The Accelerator
Topic: Weekend of 12-3-09 collision events !
Replies: 188
Views: 22982

Re: *** COLLISION ALERT ***

This process is just as important, detailed and complex as running the LHC. Its also a whole separate process that I know little about as its kinda secret. It's not secret at all. What is secret are the results until they are approved by the collaboration (you don't want Mr. Scientist no. 1 making ...
by LHC_Insider
Sat Dec 05, 2009 4:55 pm
Forum: The Accelerator
Topic: Weekend of 12-3-09 collision events !
Replies: 188
Views: 22982

Re: *** COLLISION ALERT ***

Told you ! They are sneaky ! I never know quite how public the schedule is, so I just chuckle to myself with pessimistic (as compared to the actual schedule which is publicised twice daily internally) suggested dates people come up with :) Lots going on, as said, hoping for a decent physics run ton...
by LHC_Insider
Wed Dec 02, 2009 9:42 am
Forum: The Accelerator
Topic: 12/2/09 power loss and many systems down
Replies: 25
Views: 11234

Re: *** MAJOR power loss and many systems down

I dont think it will cause almost any delay. It appears The LHC stayed cold and wont need to be re chilled. I would think mostly rebooting and such.. It takes weeks to warm up a sector if cryo goes. A few hours with tripped power is nothing. The power cut was into the Meyrin site. The induced effec...
by LHC_Insider
Tue Dec 01, 2009 2:09 pm
Forum: The Accelerator
Topic: Old Breaking news 11/30-12/2/09
Replies: 20
Views: 8698

Re: *** Breaking news ***

chriwi: Yes, you can think of them that way. However, a point of clarity: The solenoids and tracking systems are momentum spectrometers, not mass spectrometers. The combination of energy and momentum measurements allow us to determine a particle's mass. Danny252: There must be machine software tests...
by LHC_Insider
Tue Dec 01, 2009 11:14 am
Forum: The Accelerator
Topic: Old Breaking news 11/30-12/2/09
Replies: 20
Views: 8698

Re: *** Breaking news ***

Hi Chriwi, The beams are always passing through the experiments, there are no by-passes. The experimental solenoids are an integral part of the measuring capabilities of the detectors. For each type of particle we can observe, we care about a few main variables: 1. Its charge (+1, 0, or -1) 2. Its m...
by LHC_Insider
Tue Dec 01, 2009 9:45 am
Forum: The Accelerator
Topic: Old Breaking news 11/30-12/2/09
Replies: 20
Views: 8698

Re: *** Breaking news ***

Now you just gotta share some insight into that "candidate" collision data Now I'm afraid that I can't do - anything made public has to be approved by the whole collaboration (within each experiment, that is - CMS don't approve ATLAS results, for example). However, this morning, the first paper was...
by LHC_Insider
Mon Nov 30, 2009 10:44 pm
Forum: The Accelerator
Topic: Old Breaking news 11/30-12/2/09
Replies: 20
Views: 8698

Re: *** Breaking news ***

Collisions at this level or even greater can't be far away. For a given definition of 'far away'... There are many things to bear in mind. Firstly, we currently only have one bunch per beam, and that bunch is pretty puny (the 'Inject probe' you see mentioned). To get meaningful collision data, we n...
by LHC_Insider
Sun Nov 29, 2009 9:35 am
Forum: The Accelerator
Topic: Schedule
Replies: 7
Views: 2463

Re: Schedule

Similar to Photons and Pair Production? Yes, it's exactly the same thing happening - a force carrier (more lingo: Gauge Boson) decays to two available states with the same net charge. However, the interactions describing quarks and gluons (QCD) are much more complicated than those describing photon...
by LHC_Insider
Sat Nov 28, 2009 11:28 pm
Forum: The Accelerator
Topic: What exactly is pre-cycling?
Replies: 6
Views: 3419

Re: What exactly is pre-cycling?

The pre-cycle is indeed the step before injection of a new beam, however it's not just a stable state. Following a ramp-down of the magnets from the previous fill, there are various residual effects in the magnets (for those who know physics lingo, this are hysteresis effects). These need to be esse...
by LHC_Insider
Sat Nov 28, 2009 11:17 pm
Forum: The Accelerator
Topic: What does ... mean?
Replies: 28
Views: 15406

Re: What does ... mean?

What does "quiet beam" mean? It means that the operators are not playing with it, the profile is understood (i.e. the spread in 3 dimensions), and it can be considered stable. This means that experiments can choose to turn on sensitive inner detectors that could be damaged by bad beam conditions. N...
by LHC_Insider
Sat Nov 28, 2009 11:13 pm
Forum: The Accelerator
Topic: Schedule
Replies: 7
Views: 2463

Re: Schedule

Proton-Proton ... Nothing too special happens apart from seeing what they fall apart into (and then what these things do). Proton-Antiproton is more fun - matter-antimatter annihilation! I'm afraid you are incorrect here... An (anti)proton isn't just made up of the three quarks one gets told about ...