The Quote Of The Week - Those Hot Boards
    By Tommaso Dorigo | October 25th 2013 02:14 AM | 4 comments | Print | E-mail | Track Comments
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    I am an experimental particle physicist working with the CMS experiment at CERN. In my spare time I play chess, abuse the piano, and aim my dobson...

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    "The question is not whether these boards will catch fire or not. The question is when they will".

    (Said by Fermilab electronics experts who were members of a review panel that provided advice on the construction of a prototype of fast-tracker hardware boards that had been designed for CDF for Run I. The boards were meant to process online data from the CDF tracker at trigger level 2. The boards were redesigned and eventually worked very reliably (no fires!)).


    A bit of detective work to find out what this was about, and I came up with this:
    N. GRION
    Istituto Nazionale di Fisica Nucleare, 34127 Trieste, Italy
    The CHAOS Collaboration

     . . . .

    CHAOS is a magnetic spectrometer which was designed for the detection  of multi­particle events in the medium­ energy range.

    the CHAOS first level  trigger hardware (CFT)

    The CFT hardware consists of  three coaxial cylindrical layers of fast­ counting detectors. The first two layers  are NE110 plastic scintillators 0.3 cm and 1.2 cm thick, respectively. . .
    It seems to me, what with all that plastic, little wonder that those layers would catch fire!

    A diagram of CHAOS, from the paper:

    Robert H. Olley / Quondam Physics Department / University of Reading / England
    Hi Robert,

    there's only 18000 or so three-letter combinations. The thing you point at is a different one. We are talking about the CDF detector construction here. It had a tracker which required a fast triggering in few microseconds. Hardware boards had to process the information coming from the wire chamber in real time and convert it into tracks of charged particles, on which one could judge whether to collect the event.

    I don't know why, but my tought went immediately
    to solid tantalum capacitors.

    Now you sparked our curiosuty, what was the problem?

    THe problem was the bad design of the boards, which would be unable to dissipate the large power drawn by their electronic components.