First fiber tests

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A first look

  1. The first batch of 50 fibers have arrived at Jlab, Mon. Feb. 15 2009
  2. The fiber lot number is 090128-2.
  3. The first fiber scans have been performed with scans from 50 cm to 320cm using a 25muCi Sr90 source.

The first fibers scanned were fiber 8, 4 and 1
Fit res fiber8.jpg Fit res fiber4.jpg Fit res fiber1.jpg
The plots show the fit parameter as a function the source position from the end of the fiber where it is read out by an XP1911 1" photo multiplier. Top left is the pedestal and its width, top right is the single photo-electron peak and width and bottom left are the background parameters. The bottom right plot shows the extracted mean number of photo electrons with an exponential fit. As seen in the plots there are some systematic dependences between the fit parameters. Also, the fit procedure sometimes fails to find the correct answer or does not converge. However, at a first glance these results show that the fibers meet the specifications in terms of more than 3.5 photo-electrons at a distance of 200cm and a bulk attenuation length larger than 300cm.