1. Endcap Crystal Properties
David Britton, Imperial College, February 2002
ACCOS Data for the
2001 crystals ( )

2. Precision NUF Measurements
Data from
18 of the
2001 Crystals
HPMT
Co60 Source
Crystal

3. Transmission Measurements
4 Crystals setup for
Longitudinal measurement
Integrating Sphere
Typical Transverse Transmission Curves
at 350nm for two different crystals
“R-slope”
“F-slope”
Spectrometer (CCD array)
Xe Lamp beam

4. R-Slopes Vs Wavelength
Crystal 2386 (FNUF = 0.55%/X0)
(Typical of normal FNUF crystals)
“GradRS”
Crystal 2379 (FNUF = 1.03%/X0)
(Typical of high FNUF crystals)

5. Correlation between NUF and GradRS
Conclusions
ACCOS light yield data are supported by higher precision measurements.
A correlation exists between FNUF and the transverse transmission (either the GradTT or GradRS parameters).
The anomalous FNUF crystals show a sudden change in the slope of the TT between 350nm and 380nm.