ELJEN Products List EJ-301 Liquid Scintillator distributed by
This scintillator exhibits excellent pulse shape discrimination (PSD) properties, particularly for fast neutron counting and spectrometry in the presence of gamma radiation.  It is identical to widely reported NE-213 and, therefore, exhibits all of the properties of that scintillator.
EJ-301 can be supplied ready for immediate use encapsulated at the factory in sealed aluminum or glass cells of a variety of types made to the customer's required dimensions.  It is also supplied in bottles or drums sealed under inert gas.   However, after being transferred to a cell or tank it should be deoxygenated again by sparging with pure nitrogen or argon for a duration proportional to the cell size immediately before sealing in order to achieve excellent PSD performance.

  Light Output (%Anthracene) 78% EJ-301 Emission Spectrum
  No. of Blue Photons
  per 1 MeV of Electron Energy
  Wavelength of Maximum Emission 425 nm
  Specific Gravity 0. 874
  Atomic Ratio, H:C 1. 212
  No. of C Atoms per cm3 3.98 x 1022
  No. of H Atoms per cm3 4.82 x 1022
  No. of Electrons per cm3 2.27 x 1023
  Flash Point (T.O.C.) 26°C (79°F)
  Mean Decay Times of
  first 3 Components ( ref. 1 )
  3.16 ns,   32.3 ns  &  270 ns
  Refractive Index 1.505
  Decay Time (short component) 3.2 ns
  No. of Photoelectrons per kev energy loss using an RCA-8575 PMT (ref. 1) 1. 7
  Alpha/Beta Ratio, "fast" (ref. 2) 0. 073
  Alpha/Beta Ratio, "slow" (ref. 2) 0. 098

Pulse Shape Discrimination
PSD figure of merit, M, is defined as the separation between the neutron and gamma peaks divided by the sum of the FWHM of the neutron and gamma peaks at 1 MeV electron energy.  Measurements of 3.5 [ref. 3, Fig. 1] and 3.9 [Ref. 4, Fig. 6] have been reported. PSD figure of merit, D, defined as the separation between neutron and gamma peaks divided by the variance in the PSD signals at 1 MeV electron energy is 11.3 [Ref. 3, Fig. 1].

For values of M and D at other energies and for electron rejection ratios, see Figs. 3a, 3b, & 4 of Ref. 3 and Fig. 6 of Ref. 4.

Response to Protons:
E=0.83P - 2.82 (1-exp(-0.25P E0.93) where P is the proton energy in MeV and E is the electron energy in MeV that gives the same light output in the range 1-300 MeV. [Ref. 5]  A more precise study in the energy range 5-17 MeV developed the following relationship [Ref. 6].

Neutron and Gamma Spectrometry
The absolute differential efficiency and neutron spectra for a nominally 5 cm dia. x 5 cm cell for energiesbetween 0.2 and 22 MeV are presented in reference 7.  Gamma spectra analysis at energies above 3 MeV taken with three different sized scintillators is presented in Ref. 8.  Methods of analyzing neutron and gamma spectra are compared in Ref. 9. Ee(MeV)=-1.092 + 0.5517Ep + 0.00461Ep²

1. F.T. Kuchnir & F.J. Lynch, "Time-Dependence of Scintillators and the Effect on P.S.D.", IEEE Trans. Nucl. Sci., NS-15, No. 3, (1968) 107-113
2. J.B. Czirr, "The a/ß Ratio of Several Organic Scintillators", Nucl. Instr. & Meth. 25 (1963) 106-108
3. R.A. Winyard and G.W. McBeth, "Pulse Shape Discrimination in Inorganic and Organic Scintillators", Nucl. Instr. & Meth. 98 (1972) 525-533
4. J.M. Adams and G. White, "A Versatile Shape Discriminator for Charged Particle Seperation and its Application to Fas Neutron Time-of Flight Spectroscopy", (<100 keV - 20 MeV), Nucl. Instr. & Meth. 156 (1978) 459-476
5. R.A. Cecil et al, "Improved Predictions of Neutron Detection Efficiency for Hydrocarbon Scintillaotrs from 1 MeV - to about 300 MeV", Nucl. Instr. & Meth. 161 (1979) 439-447
6. A. Aksoy et al, "Response-Function Measurements of an NE-213 Scintillator Using the 2H(d,n)3He Reaction", Nucl. Instr. & Meth. In Phys. Res. (1994) 486-491
7. V.V. Verbinski et al, "Calibration of an Organic Scintillaotr for Neutron Spectrometry", Nucl. Instr. & Meth. 65 (1968) 8-25
8. L. Buermann et al, "Response of NE-213 Liquid Scintillation Detectors to High-energy Photons (Eg>3 MeV)", Nucl. Instr. & Meth. in Phys. Res. A332 (1993) 483-492
9. R. Koohi-Fayegh et al, "Neural Network Unfolding of Photon and Neutron Spectra Using and NE-213 Scintillation Detector", Nucl. Instr. & Meth. In Phys. Res. A329 (1993) 269-276

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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