UK research laboratory working with industry to deliver electronics helping to unravel the mysteries of the Big Bang. 

CCLRC Rutherford Appleton Laboratory in partnership with UK industry has recently successfully delivered a major electronics system for the Large Hadron Collider at CERN. 

A Tracker Front End Driver Board

Public material on CERN and LHC at   http://press.web.cern.ch/public/   Public material on the CMS experiment at   http://cmsdoc.cern.ch/cms/outreach/html/index.shtml   Public material on the CMS Tracker at  http://cmsdoc.cern.ch/Tracker/Tracker2005/TKoutreach/   For further information contact :  Dr John Coughlan CCLRC Rutherford Appleton Laboratory

The Compact Muon Solenoid (CMS) experiment at CERN will be one of the world’s biggest particle detectors when it starts taking data in 2007.  CMS is one of the major experiments at the new CERN facility the Large Hadron Collider (LHC) which is located in a 27 kilometre circumference circular tunnel 100 metres beneath the Swiss-French border near Geneva. A team of thousands of particle physicists, electronics engineers and construction experts are building CMS piece by piece, in locations all around the world. The particle collisions in the LHC will recreate inside a tiny volume the physical conditions which were present in the Universe just after the Big Bang.

In the UK, one of the collaborating institutes is the CCLRC Rutherford Appleton Laboratory (RAL).  Here, around 500 large and complex electronics boards for the readout of the CMS silicon tracking detector are being produced, tested and shipped out to CERN.  

The Tracker Front End Driver (FED) board project began at RAL almost 10 years ago. In 2004 a UK company, eXception EMS ltd in Wiltshire, won a European wide tender to manufacture the FED boards which were designed at RAL. The company has worked closely with RAL throughout and with the production phase close to completion, the final few FED boards are being tested at RAL in spring 2006 before being shipped out to CERN.

The main job of the FED board is to receive data from the silicon detectors inside the CMS main detector.  40 million particle collisions will occur every second inside CMS.  A trigger system selects 100,000 of those collisions each second as interesting events and these are fed through to the FEDs as laser light pulses along huge bundles of optical fibres.  40,000 optical fibres in bundles that are 70 metres long, carry data from the CMS detector to racks of FED boards in another cavern which like the detector is also100m underground.

Each particle collision, or event, produces about 10,000,000 Bytes of silicon detector data and an individual FED board will handle 3,000,000,000 Bytes of data each second. The whole FED system processes the equivalent of the contents of 2,000 CDs every second and must operate for several months each year.

The FED boards keep about 5% of the information on each event, extracting data from only the silicon strips in the tracking detector that have registered particle hits.   Each FED board corresponds to a specific part of the CMS tracker, and so when the output from each FED board is passed through a switch system, the data is assembled and combined to create a picture of the whole particle collision inside CMS.

The team designing and producing the FED boards have had to think of everything - if the particle events are different to predictions, the team will need to reprogramme the algorithms the board uses to process the data.  This is achieved by incorporating clever chips called FPGAs – Field Programmable Gate Arrays – into the board design. 

The successful manufacture of high quality boards has won eXception EMS ltd a CMS Industry Gold Award prize in 2006.