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GENERAL PURPOSE

EJ-200, EJ-204, EJ-208, EJ-212

 

EJ-200, EJ-204, EJ-208, EJ-212

 

These scintillators have the properties of long optical attenuation length and fast timing with an emission spectrum well matched to common photomultipliers.

EJ-200 combines the two important properties of long optical attenuation length and fast timing which make it particularly useful for time-of-flight systems using scintillators greater than one meter long. It is the detector of choice for many industrial applications, such as gauging and environmental protection, where high sensitivity and signal uniformity are critical operating requirements.

EJ-204 has the highest scintillation efficiency of any of Eljen’s plastic scintillators, along with the combination of high speed and good attenuation length. It is particularly well suited for high-performance detector systems for nuclear and high-energy physics research. Its emission wavelength near 400 nm couples ideally with bialkali phototubes while still being long enough to be effectively used with UVT light guides.

EJ-208 possesses the longest wavelength emission of commonly available blue scintillators and hence should be considered for applications requiring complex or extended light guides. The long emission spectrum provides additional resistance to radiation damage of which the most common symptom is increased optical attenuation at short wavelengths. It is intended specifically for use in large sizes where timing is of secondary importance and uniformity of light collection is paramount.

EJ-212 is a scintillator specially formulated for use in thin sheets (thickness less than 5 mm), but it can also be used in thick cast sheet, rods and ingots. Applications include industrial and health physics measurement of alpha, beta, gamma, and neutron radiation as well as in numerous medical instruments and scientific research ranging from low background shields in nuclear physics to space-borne astrophysics systems. It is best utilized in sizes up to 100 cm long. EJ-200 should be considered for longer pieces.

 

PROPERTIES EJ-200
EJ-204
EJ-208
EJ-212
Light Output (% Anthracene) 64 68 60 65
Scintillation Efficiency (photons/1 MeV e-
10,000 10,400 9,200 10,000
Wavelength of Maximum Emission (nm) 425 408 435 423
Light Attenuation Length (cm) 380 160 400 250
Rise Time (ns) 0.9 0.7 1.0 0.9
Decay Time (ns) 2.1 1.8 3.3 2.4
Pulse Width, FWHM (ns) 2.5 2.2 4.2 2.7
No. of H Atoms per cm3 (x1022) 5.17 5.15 5.17 5.17
No. of C Atoms per cm3 (x1022) 4.69 4.68 4.69 4.69
No. of Electrons per cm3 (x1023) 3.33 3.33 3.33 3.33
Density (g/cm3) 1.023 1.023 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 20°C to -60°
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-200 Emission Spectrum

EJ-204 Emission Spectrum

EJ-208 Emission Spectrum

EJ-212 Emission Spectrum