ELJEN Products List EJ-232 fast timing
plastic scintillator
distributed by
This plastic scintillator is intended for very fast timing applications or when very high pulse pair resolution is required.   In all such counting situations the scintillator must be used in a small size, typically with the largest scintillator dimension less than 10 cm, to minimize photon scattering effects.   The use of light guides is also best avoided.
The short wavelength of EJ-232 couples well with standard bialkali phototubes.   Also, the unique formula of EJ-232 ultra fast counting using quenched versions of this material, EJ-232Q.   The most common quenching being with 0.5% benzophenone, achieving 700 ps pulse width and light output od 19% anthracene.

Physical and Scintillation Constants:
Light Output, % Anthracene 55% EJ-232 emission spectrum
Scintllation efficiency, photons/1MeV e¯ 8,400
Wavelength of max emission, nm 370
Rise Time, ns 0.35
Decay Time, ns 1.4
Pulse Width [FWHM], ns 1. 3
No. of H atoms per cm3 x 1022 5. 19
No. of C atoms per cm3 x 1022 4. 71
No. of electrons per cm3 x 1023 3. 34
Density, g/cc 1. 032
  Polymer Base:   Polyvinyltoluene
Refractive Index:   1. 58
Vapor Pressure:   Is vacuum-compatible
Coefficient of Linear Expansion:   7. 8 x 10¯5 below +67°C
Light Output vs. Temperature:   at +60°C, L.O.=95% of that at +20°C
  No change from +20°C to -60°C
Chemical Compatability: Is attacked by aromatic solvents, chlorinated solvents, ketones, solvent bonding cements, etc.  It is stable in water, dilute acids and alkalis, lower alcohols and silicone greases. 
It is safe to use most epoxies and "super glues" with EJ-232.

G-tech, Corp.    local representative in Japan
365-1, Sayamagahara, Iruma-shi, Saitama 358-0032
Phone# 04-2935-2777 Fax# 04-2935-2778  

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