The number of photoelectrons per MeV and uniformity of three crystals
have been measured, using three different preparation methods. The first
method involves wrapping the crystal in two layers of teflon and
one layer of mylar. The second is the same as the first, except that
the surface of the crystal is painted with the Ukraenian wavelength
shifting lacquer. The third method of preparation involves painting
the surface of the crystal with the lacquer and wrapping the crystal
in one layer of mylar. These preparation methods have been abbreviated
"1", "2", and "3" respectively, and have been appended to the appropriate
data file names and graph titles.
The number of photoelectrons per MeV (N) was calculated from the slope
of a graph of sigma squared vs. energy for each crystal. N was measured for
S003 in treatments 1-3, S125 in treatments 1-2, and S128 in treatments 1-3
with the following results, including temperature corrections:
S003-1b: 113, 104
S003-2a: 67, 75
The error in these measurements was found to be on the order of 10 photo
electrons per MeV.
Next, the light output uniformity of each crystal was measured.
S003 has been analyzed in treatments 1-3, S125 in treatments 1-2, and
S128 in treatments 1-3. For each crystal and each treatment, scatter
plots of axial, transverse, and two dimensional uniformity are shown below.
For axial uniformity, the first scatter plot includes all muon path lengths,
the second contains only muons with path lengths greater than 5 cm, and the
third contains muons with path length less than 5 cm. For transverse
uniformity, the first scatter plot describes the entire crystal, while
the next four plots involve specific regions of the crystal along the
z-axis. The slopes of the scatter plots are shown below, in the following
order: Axial(0:10cm), Axial(10:18cm), Axial(18:22cm), Transverse(z=2:4cm)
Left, and Transverse(z=2:4cm) Right.