General Meeting Summary 3/6/14

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  • Most components for prototype have been ordered (e.g., components for HV dividers, photodiode etc.).
  • Action item: Need a list/cost estimate of all remaining materials that are not available.
  • Planning to do transmission measurements with two PbWO4 crystals in two different measurement setups (C. Zorn's and at CUA) to compare methods. Currently have only one crystal, but there are some options to get a second.
  • Action item: get a second PbWO4 crystal ideally of same dimensions as those that we will actually use for the NPS.


  • Discussion about if the prototype box should be made of copper or aluminum. There are arguments in favor of either. If thermal properties are not important for the planned tests of radiation damage then Aluminum may be ok. On the other hand, for radiation tests copper may not be optimal - recall the experience with the SHMS bender prototype. To address questions of the optimal temperature to optimize light output and radiation damage (with beam during DVCS running) the thermal properties of the box material would be important.
  • Action item: make a comparison of the cost of the box and weight using either material and then decide.


  • Discussion about selection of the primary light source for a prototype consisting of both PbWO4 and PbF2 crystals (with different pulse lengths and shapes). For example, PbF2 pulse rises/falls faster. Do we need different light sources for these two crystals?
  • Discussion about the quantitative result of the effect of the light pulse, e.g., length, shape, and timing. NPS LMS will make relative measurements, e.g., monitoring one crystal to its own baseline and not to other crystals and pulse shape doesn't matter too much for electronics.
  • In general, for properly chosen wave length the difference between the two types of crystals should not be too large. If there is no significant difference in the transparency of the two crystals for the wave lengths of the light source we are planning to use for LMS (blue light of >~400 nm) then one primary light source should be fine.
  • Action item: make transmission measurement for PbWO4 and PbF2 crystals to quantify the transparency with the blue light source we are planning to use.


  • Communication with DAQ/electronics group ongoing about availability of components needed for tests

CALOR 2014:

  • Abstract was accepted and at least one member of NPS collaboration will attend


  • Proposal was submitted to European competition