Test Beam Madness

07.13.09

posted by: dberry

I just finished a bunch of shifts on the ECAL test beam. This summer, the ECAL group ran a test beam at the H4 Prevessin site. The test beam consists of a stream of high energy electrons. Our beam of electrons was generated by the SPS (Super Proton Synchrotron). The proton beam is smashed into a high Z element (like tungsten) to produce pions. The neutral pions are separated off and they decay to photons. The photons are then smashed into a lighter target (such as copper) and it produces high energy electrons.

The high energy electrons are then sent to a 5×5 crystal tower. We then move the crystal tower such that the beam lands on a specific crystal. The first thing we did in the experiment was characterized a normal 5×5 crystal tower. Then we changed out two of the crystals. One crystal was replaced with a radiation damaged crystal, and the other one was made out of a material which is more resistant to radiation damage. We then remeasured the crystal towers response. The data hasn’t been analyzed yet, so I can’t post any results. But below is a picture of the radiation damaged crystal.

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This entry was posted on Monday, July 13th, 2009 at 10:01 am and is filed under CERN. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

6 Responses to “Test Beam Madness”

  1. Tom Loughran Says:
    July 14th, 2009 at 6:44 am

    Doug,

    What’s the crystal made of, and who makes it?

    Can you get an image of the 5×5 array?

  2. dberry Says:
    July 14th, 2009 at 6:59 am

    This is a radiation damaged lead tungstate crystal (PbW04). They are made by the Russians and Chinese because the process produces such a large amount of toxic pollution that they cannot be made in the US or Europe.

    I will try to get a picture of the 5×5 crystal array.

  3. Tom Loughran Says:
    July 14th, 2009 at 7:51 am

    Thanks, Doug!

  4. jziegler Says:
    July 14th, 2009 at 1:14 pm

    Doug, what kind of radiation damage? In other words, what happened to the crystal with what kind of radiation to damage it? Was it accidental or on purpose? Why choose to test a crystal with radiation damage at all?

  5. dberry Says:
    July 21st, 2009 at 2:47 am

    The crystal was damaged with gamma radiation. The crystal was intentionally damaged with gamma radiation because we can study it and understand how our detector response will change with exposure to gamma radiation.

  6. jziegler Says:
    July 21st, 2009 at 9:29 am

    That makes sense.
    Thanks, Doug!