Current Events Discussion

The place to discuss the LHC. Commissioning, operation, issues, events ....
User avatar
LarryS
Posts: 100
Joined: Fri Dec 04, 2009 3:46 pm
Location: Seymour, CT, USA

Re: Current Events Discussion

Post by LarryS » Tue Jul 13, 2010 9:40 pm

Does anyone know the buckets involved with the 12b_8_8_8? I have found information on 13b_8_8_8 but not the 12b.

Thanks

User avatar
LarryS
Posts: 100
Joined: Fri Dec 04, 2009 3:46 pm
Location: Seymour, CT, USA

Re: Current Events Discussion

Post by LarryS » Tue Jul 13, 2010 10:36 pm

Found the bucket numbers on the e-log; hope I did not put anyone to any trouble

Thanks

User avatar
terryburton
Posts: 13
Joined: Thu Mar 11, 2010 11:44 am

Re: Current Events Discussion

Post by terryburton » Tue Jul 13, 2010 11:38 pm

Hi,

The filling schemes are detailed here:

http://lpc.web.cern.ch/lpc/fillingschemes.htm


HTH,

Tez

User avatar
LarryS
Posts: 100
Joined: Fri Dec 04, 2009 3:46 pm
Location: Seymour, CT, USA

Re: Current Events Discussion

Post by LarryS » Wed Jul 14, 2010 12:04 am

Thanks, however I had found that site a day or so ago and the 12b was not there; it has been added since I last visited the site.

tomey36
Posts: 103
Joined: Wed Apr 14, 2010 11:39 pm

Re: Current Events Discussion

Post by tomey36 » Wed Jul 14, 2010 5:27 am

does anyone know if the events in the ATLAS live display, are minimun bias events or the ones that pass though the high level triggers.

User avatar
PhilG
Posts: 135
Joined: Sun Dec 06, 2009 9:58 pm
Contact:

Re: Current Events Discussion

Post by PhilG » Wed Jul 14, 2010 3:28 pm

Today's run was the best yet with about 15 hours of stable beams and luminosities above 1.0 for most of the run. No sign if the sharp losses seen on previous runs. integrated luminosity was about 50 inverse nanobarns taking accumulated total to around 200 inverse nanobarns. LHC is starting to behave itself. Run was finally ended by an electrical network glitch.

User avatar
CharmQuark
Site Admin
Posts: 1469
Joined: Fri Dec 04, 2009 2:22 am
Location: Berwick-Upon-Tweed (UK)

Re: Current Events Discussion

Post by CharmQuark » Wed Jul 14, 2010 5:19 pm

i like this :thumbup:
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.

User avatar
ikarus177
Posts: 12
Joined: Sun Jul 04, 2010 2:10 pm

Re: Current Events Discussion

Post by ikarus177 » Thu Jul 15, 2010 3:30 pm

They are currently hunting the Hump by switching off the "GSM" in the tunnel.
I wonder if this is the same GSM that we use for wireless communication?

ikarus177

MpVpRb
Posts: 4
Joined: Wed Apr 07, 2010 2:02 am

Re: Current Events Discussion

Post by MpVpRb » Thu Jul 15, 2010 3:33 pm

I'm confused...

The last post said...
taking accumulated total to around 200 inverse nanobarns
But I read an article that said...
The goal in the next year is to get to one inverse femtobarn
Femto is smaller than nano.

What are the rules for calculating with inverse xxbarns?

User avatar
DCWhitworth
LHCPortal Guru
Posts: 571
Joined: Mon Nov 30, 2009 8:13 am
Location: Norwich, UK

Re: Current Events Discussion

Post by DCWhitworth » Thu Jul 15, 2010 3:46 pm

MpVpRb wrote:I'm confused...

The last post said...
taking accumulated total to around 200 inverse nanobarns
But I read an article that said...
The goal in the next year is to get to one inverse femtobarn
Femto is smaller than nano.

What are the rules for calculating with inverse xxbarns?
I think the key word here is 'inverse', why they seem to do this backwards I'm not sure, some scientific reason no doubt, but personally I think a Gigabarn sounds better :)
DC

The LHC - One ring to rule them all !

User avatar
PhilG
Posts: 135
Joined: Sun Dec 06, 2009 9:58 pm
Contact:

Re: Current Events Discussion

Post by PhilG » Thu Jul 15, 2010 3:50 pm

femtobarn is smaller than nanobarn, so inverse femtobarn is bigger than inverse nanobarn. It is terminology designed to confuse. They should just call an inverse barn a narb so that they can talk about Meganarbs, Giganarbs , Teranarbs etc.

So now they have about 240 Giganarbs. They are aiming for 100 Teranarbs this year and a Petanarb by the end of 2012. That make more sense?

User avatar
DCWhitworth
LHCPortal Guru
Posts: 571
Joined: Mon Nov 30, 2009 8:13 am
Location: Norwich, UK

Re: Current Events Discussion

Post by DCWhitworth » Thu Jul 15, 2010 6:24 pm

PhilG wrote:femtobarn is smaller than nanobarn, so inverse femtobarn is bigger than inverse nanobarn. It is terminology designed to confuse. They should just call an inverse barn a narb so that they can talk about Meganarbs, Giganarbs , Teranarbs etc.

So now they have about 240 Giganarbs. They are aiming for 100 Teranarbs this year and a Petanarb by the end of 2012. That make more sense?
Yes but isn't the aim to produce one inverse femtobarn at 14 TeV centre of mass ? Since the machine is operating at only 7 TeV presumably this won't be adding to this total.
DC

The LHC - One ring to rule them all !

Kasuha
Posts: 569
Joined: Tue Dec 15, 2009 1:22 pm

Re: Current Events Discussion

Post by Kasuha » Thu Jul 15, 2010 7:37 pm

MpVpRb wrote:
The goal in the next year is to get to one inverse femtobarn
Femto is smaller than nano.

What are the rules for calculating with inverse xxbarns?
Let's make an example in better understandable scales (but as a result, waaaay out of the real scale). Imagine the beam cross-section is one square meter. So far they got 10 collisions per square decimeter (10 inverse dm2s), which means one thousand collisions total. They aim for one collision per square milimeter (1 inverse mm2), which is smaller number and smaller area but in fact it means much more - one million of collisions total.

It's similar with nano- and femtobarns as they are also units of beam cross-section area. They are using these tiny area units to illustrate how well the target (proton in opposite direction) has been probed. Inverse femtobarn is way smaller than proton cross-section so it gives good chance that all possible scattering angles have been sufficiently probed.

User avatar
PhilG
Posts: 135
Joined: Sun Dec 06, 2009 9:58 pm
Contact:

Re: Current Events Discussion

Post by PhilG » Thu Jul 15, 2010 9:24 pm

DCWhitworth wrote:Yes but isn't the aim to produce one inverse femtobarn at 14 TeV centre of mass ? Since the machine is operating at only 7 TeV presumably this won't be adding to this total.
The rough plan is one inverse femtobarn at 7TeV by end of 2011 and 60 inverse femtobarn at 14Tev by end of 2016.
See https://indico.desy.de/getFile.py/acces ... onfId=1964

MpVpRb
Posts: 4
Joined: Wed Apr 07, 2010 2:02 am

Re: Current Events Discussion

Post by MpVpRb » Fri Jul 16, 2010 6:16 pm

So...I'm still confused about inverse xxbarns.

If smaller numbers mean more data, why do the numbers increase over time on these plots?

http://lpc.web.cern.ch/lpc/lumiplots.htm

Post Reply