The Zero Hour Approacheth - Again

Hello, all,

Once again - long time, no blog. You can well imagine, as I had predicted, that things have been crazy busy for us. Nevertheless I felt it necessary to take this "brief pause for station identification". As promised, the LHC is on a trajectory of re-startup leading to circulation of beam and collisions. Already now they have performed injection tests into all of the rings including the big LHC ring. This is where the proton bunches enter the ring but don't circulate all the way around.

But before I write further on this, a wrap-up of what's gone on in the past. You may recall I was working on a paper with two professors, one being my adviser. This paper is one of about 25 or so that are proceeding towards publication. The contents of the papers are all about data taken a year ago when we were at this stage, when beam was just starting to circulate in the LHC before the incident, and the "Cosmic Run At Four Tesla" (CRAFT) month-long run we performed after the incident. My particular paper is about hadron calorimeter timing and synchronization.

These papers have multiple review cycles; the paper I worked on went as follows:

• Started writing in May of this year.
• Internal HCAL review July 1-15, followed by...
• submittal to an "ARC" (analysis review committee) on the 20th . (Recall we moved on the 16th-17th.) My ARC consisted of 4 members, an Indian at UCSD, an American at Fermilab, and a Russian and an Englishman both stationed here in Switzerland.
• The ARC rejected the first submittal at the end of July, told us to rewrite. This happened with many of the CRAFT papers.
• Two more weeks of intense rewrite, followed by resubmittal August 18 (after which I took a break to spiff up the apartment, a month late, and take the family to Annecy for a much-deserved day off).
• Four weeks later, we received our first set of comments from the ARC. Two more weeks of intensive editing and iterations with the ARC, finalized by submittal on September 30 and approval from the ARC to proceed to the next phase...
• Collaboration-Wide Review (CWR). Since all papers of this type have "The CMS Collaboration" as the listed author - with pages and pages of appendix listing each one individually - the whole collaboration gets a chance to comment on the paper. Since the CMS Collaboration is reported in 2005 to be the largest scientific collaboration ever assembled, one might think this to be quite daunting. But when you're in a crowd of 25 papers, who's going to have the time to review all of them? Most won't opt to review even one, or perhaps at most one if it's in their area of expertise. So participating institutions are assigned different papers to review, and this paper was assigned to three institutions for review: Princeton, Budapest, and CERN. In addition, 5-6 individuals also submitted their comments. The first 2-3 weeks of October were given to the collaboration to submit comments, and the rest of October was essentially used to respond to these comments and come up with a final draft that the Authors and the ARC agreed upon, which leads to...
• The Final Reading (said with a loud booming echo-y voice) - and no, this doesn't mean the last time the paper will ever be read! (Just one of...) It's scheduled for this coming Tuesday. Only major comments are accepted at this time. If all goes well at the FR (no echo), then the paper is submitted to the Journal of Instrumentation - at which point the editors of the journal are also free to submit comments and require changes to be made!

The whole activity has gone on a lot longer than we expected, but then we were also expecting LHC startup to happen earlier too, at the end of September. The activity was essentially designed to end when this occurred, and that leads me back to the opening topic.

I just lurch from one crisis to the next: now that the paper is mostly done, this week we are told we will receive "splash events" at CMS. These are events just like the ones that are reported in the paper from last year. To quote one of the papers:

The beam-produced muons, collected by CMS when the first beams circulated in LHC in September 2008, are used to synchronize the detector. The beam was
dumped on the collimators located at approximately 150 m upstream with respect to CMS, producing the so-called ”beam splash” events. The size of a single proton bunch along the direction of propagation was about 6 cm. The resulting pions created by the collision with the collimator decayed into a very large number of muons moving horizontally along the beam direction at close to the speed of light.

As stated, we use splash events to help synchronize all the channels in HCAL. So while the FR (no echo) is scheduled for Tuesday, I'm also scheduled to give a talk on Wednesday about our readiness to quickly analyze the splash data and calculate new settings we download to the "front-end electronics". So I'm trying to crank out the software and get it ready in less than a week...And that reminds me, I didn't even mention my work on the "RBXManager" software, for which I'm told I will be receiving an achievement award in December, thank you Jeremy...

The plan now with the LHC is to achieve collisions at 1.1TeV per beam before the end of the year. Ramp-up to 3.5TeV per beam is slated for next year after the brief Christmas shutdown. For those interested you can see a detailed schedule right here.

I may or may not add to this blog entry as things progress, I do have more things to report, of course! Just wanted to get this out there for people...

Take care,
-PKBGD