N‐(2‐Ethylhexyl)carbazole: A New Fluorophore Highly Suitable as a Monomolecular Liquid Scintillator

Abstract

The synthesis, photophysical properties, and applications in scintillation counting of N-(2-ethylhexyl)carbazole (EHCz) are reported. This molecule displays all of the required characteristics for an efficient liquid scintillator (emission wavelength, scintillation yield), and can be used without any extra fluorophores. Thus, its scintillation properties are discussed, as well as its fast neutron/gamma discrimination. For the latter application, the material is compared with the traditional liquid scintillator BC-501 A, and other liquid fluorescent molecules classically used as scintillation solvents, such as xylene, pseudocumene (PC), linear alkylbenzenes (LAB), diisopropylnaphthalene (DIN), 1-methylnaphthalene (1-MeNapht), and 4-isopropylbiphenyl (iPrBiph). For the first time, an excimeric form of a molecule has been advantageously used in scintillation counting. A moderate discrimination between fast neutrons and gamma rays was observed in bulk EHCz, with an apparent neutron/gamma discrimination potential half of that of BC-501 A.

Recent progress of organic scintillators

“…Another π-conjugated solvent, n-(2-ethylhexyl)carbazole, has also been used as fluorescent liquid for liquid scintillator. 35) It showed efficient scintillation of ∼6000 photons MeV −1 without addition of fluorescent molecules.…”

Tuning the decay time of liquid scintillators

“…2,3 Immediate interest was granted from the community 4 and the next decades have seen the positioning of liquid scintillators (LSs) at the central place of radiation detectors with numerous applications, from fundamental physics research (such as Borexino 5 or SNO+ 6 ), metrology of the activity, 7 dosimetry, 8 environmental assays 9 and various R&D activities looking at new, promising media. 10 Five different advantages of LSs can be highlighted:…”

Progress in Fast and Red Plastic Scintillators

“…4-Bromo-p-terphenyl was prepared according to a published procedure [20]; a white powder was obtained with an 80% yield after purification. N-(2ethylhexyl carbazole) was prepared according to our previous work [21]. Spectroscopic toluene was obtained from Carlo Erba.…”