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 FAST TIMING

 EJ-228, EJ-230

 

EJ-228

 

These plastic scintillators are intended for very fast timing applications or when very high pulse pair resolution is required. The use of light guides is best avoided.

EJ-228 should be used in small sizes for the best timing results, with the largest scintillator dimension less than 10 cm to minimize photon scattering effects. This scintillator is particularly useful where very high count rates are present.

EJ-230 is a variant on the optimized EJ-228 formula for applications where a detector dimension must exceed 10 cm. The mean free path of the scintillation emission spectrum is typically 100 cm, allowing scintillators up to 50 cm to be employed with good timing and light collection results. This scintillator is particularly useful where very high count rates are present.

 

PROPERTIES EJ-228
EJ-230
Light Output (% Anthracene) 67 64
Scintillation Efficiency (photons/1 MeV e-)
10,200 9,700
Wavelength of Maximum Emission (nm) 391 391
Light Attenuation Length (cm) - 120
Rise Time (ns) 0.5 0.5
Decay Time (ns) 1.4 1.5
Pulse Width, FWHM (ns) 1.2 1.3
No. of H Atoms per cm3 (x1022) 5.15 5.15
No. of C Atoms per cm3 (x1022) 4.69 4.69
No. of Electrons per cm3 (x1023) 3.33 3.33
Density (g/cm3) 1.023 1.023

 

Polymer Base Polyvinyltoluene
Refractive Index 1.58
Softening Point 75°C
Vapor Pressure 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 -60°C to 20°C
Temperature Range -20°C to 60°C

 

Chemical Compatibility
Attacked by: Aromatic solvents, Chlorinated solvents, Ketones, Solvent bonding cements, etc.
Stable in: Water, Dilute acids and alkalis, Lower alcohols, and Silicone greases.
It is safe to use most epoxies with these scintillators.

 

 EJ-228 & EJ-230 Emission Spectrum