Development of a Liquid Scintillator and of Data ... - Borexino - Infn

6.2.2 Optical Properties
6.2 Laboratory Measurements with PXE
The main characteristics used to describe the properties of an organic scintillator may be summarized
as:
- the scintillation emission spectrum and the transmission of this spectrum through the
scintillator;
- the variation of response with energy for different types of charged particle;
- the absolute scintillation efficiency, the response resolution and the associated energy
resolution;
- the fast timing characteristics, including the time resolution and the parameters which
describe the prompt component of the scintillation decay;
- the pulse shape characteristics, including the relative intensities of the prompt and the
delayed scintillation components for different types of particle, and the suitability of
these characteristics for particle identification by pulse shape discrimination.
Most of these items have been addressed in laboratory measurements [Eli96, Nef96, Lom97]:
- The emission spectrum of TP in PXE is shown in fig. 6.2.
- PXE/TP has a fluorescence lifetime of 3.2 ns, similar to PC/PPO (3.6 ns).
- The attenuation length of PXE/TP was measured to be 4.3 m at 430 nm (PC/PPO 3.3 m
at 430 nm).
Figure 6.2: Fluorescence spectra of TP in PC (full line) and PXE (dashed line) under excitation
at 315 nm. Taken from [Eli96].
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