New website displays statistics direct from LHC

Ian Randall

A new website is being developed which displays timely data from the LHC and the experiments. It is hoped that the LHC-statistics site will become a useful tool not only for CERN's physicists, but also in providing feedback on the performance of the machine itself.


The new LHC Performance and Statistics website

“We needed a way to see how the machine is performing, and the data that is coming back from the experiments,” says Alick Macpherson, one of the developers of the website. “The idea behind this website is to have a page that is generally accessible from inside and outside of CERN that shows the performance of the machine and gives some idea of the quality of the data provided to the experiments for the collisions.”

“We spent a lot of time last year getting the LHC up and running, and it is only natural to wonder how we're doing,” he adds. “If we want to improve the performance of the LHC we must know what that performance is.”

The site gathers the data automatically from the machine's logs and control systems in a safe and secure manner, and presents it in a number of tables of plots to give the user an overview of the current machine operation. There is a delay of only 30 minutes between the completion of a fill and the corresponding update to the site.

Designed to accommodate a number of audiences – from specialists through to management – the website offers different tiers of information, from a basic overview to the finest detail of information available. The information gathered was previously available from a number of other locations – but the new service provides a centralised, user friendly method of collecting the data – one which does not require an intimate knowledge of the LHC machine operation.

“The first thing that people want to know is what luminosity is being delivered, and also how the machine is running... this gave us the first plots,” says Macpherson. “Then a summary set of details; and then a third part with all the gory details that you could want.”

“This has to be something that is viewable by everyone, and easily accessible and understandable – because if it is too complicated, and only one or two people can understand it, then what is the point?” he adds.

The finer details are provided in the form of a large spreadsheet – referred to as the supertable – in which each fill is given a row, and the columns are populated with the various statistics related to such. At present, each fill has over 90 columns – although that is expected to increase.

Users of the site are encouraged to propose any additions to the site that they think might be useful – in fact, a request was already made – and added – by ALICE concerning the display of the crossing angles.

The site also provides the capacity for people to download the machine data for analysis: either direct from the supertable, or packaged – on a fill by fill basis – as processed root files.

Under development since January this year, the site is now up-and-running – however, the team hopes to build on the current set-up as is needed.

The site was developed by Yngve Levinsen, Alick Macpherson, and Mario Terra Pinheiro; with assistance from Shaun Roe and Eric Torrence.

“This project is driven by the idea of making the technology useable,” says Macpherson. “I would hope that the experiments find this useful, and we would welcome feedback.”

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