Detector status, Computing, Early Physics. John Huth. New LHC machine schedule. A new LHC schedule and turn-on strategy was presented to the CERN SPC and Council three weeks ago The experiments were informed only shortly before, and allowed to communicate it just after the SPC meeting
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
A new LHC schedule and turn-on strategy was presented to the CERN SPC and Council
three weeks ago
The experiments were informed only shortly before, and allowed to communicate it just after
the SPC meeting
The main features of the new schedule are:
- The beam pipe closure date will be end of August 2007 (instead of end of June 2007)
- After that there will still be a few weeks of controlled access to the cavern
- This is followed by an LHC commissioning run with collisions at the injection energy
(450 + 450 GeV), until the end of 2007
- Then there will be a shut-down (typically 3 months) during which the remaining
machine sectors will be commissioned without beam to full energy (7 TeV)
- After that the LHC will be brought into operation for the first physics run at 14 TeV,
with the aim to integrate substantial luminosity by the end of 2008
The LHC Machine Advisory Committee (MAC) has strongly endorsed this new start-up strategy as
the most efficient way to reach 14 TeV collisions
The SPC stressed that the goal should be several fb-1 integrated luminosity at the end of 2008
Milestones for the machine
- Sectors 7-8 and 8-1 will be fully commissioned up to 7 TeV in 2006-2007. If we
continue to commission the other sectors up to 7 TeV, we will not get circulating
beam in 2007.
- The other sectors will be commissioned up to the field needed for de-Gaussing.
- Initial operation will be at 900 GeV (CM) with a static machine (no ramp, no
squeeze) to debug machine and detectors.
- Full commissioning up to 7 TeV will be done in the winter 2008 shutdown
Given this new schedule situation, ATLAS stated that the start-up strategy should be
such that the useful integrated luminosity at 14 TeV at the end of 2008 will be maximized
This points towards preferring a few weeks of stable running conditions at the injection energy
as compared to possibly lengthy attempts to reach the maximum possible beam energy of 1.1 TeV
before the full commissioning of LHC power components in the winter shut-down
Primarily the run in 2007 will be a detector and computing commissioning run, much more than a
(Data taking efficiency (machine x detector) of 30% included
Efficiency of all analysis cuts included)
s = 900 GeV, L =1029 cm-2 s-1
Extensive test beam characterization of prototypes and final modules. Also used for validation of G4 simulations.
L~1030 to 1031 cm-2 s-1
L~1032 to 1033 cm-2 s-1
How many events at the beginning ?
Goal is to have several fb-1 integrated luminosity at the end of 2008!
to CDF, D0 today
~10 pb-1 1 month at
1030 and < 2 weeks
100 pb-1 few days
at 1032 , =50%
σtot ~ 102 - 118 mb
σNSD ~ 65 - 73mb
(see P. Steinberg’s talk, July 13th).
(min-bias dNchg/dη ~ 7)
dNchg/dη ~ 30
dNchg/dη ~ 15
x1.5The underlying event in pp collisions at √s = 14 TeV
pt>0.5 GeV and |η|<1
Cone jet finder:
Transverse < Nchg >
UE particles come from region transverse to the leading jet.
Pt (leading jet in GeV)
A project to engineer a technology fabric in support of interdisciplinary & collaborative computing
Joy Sircar – Division of Engineering and Applied Science
GLOW - ~1000 Procs
CG - ~750 Procs
In just 2 campuses !
Alyssa Goodman (Director)
Tim Clark (Executive Director)
Computer Science departments
Increasingly, core problems in science require computational solution
Typically hire/“home grow” computationalists, but often lack the expertise or funding to go beyond the immediate pressingneed
Focused on finding elegant solutions to basic computer science challenges
Often see specific, “applied” problems as outside their interests
Plus…Educational Programs that bring IIC Science to Harvard students, and to the public at large.