The invention relates to a compound having one of the following ionic chemical structures (I), R represents an alkyl or O-alkyl group optionally comprising one or more unsaturations, as a linear or branched chain, of 1 to 30 carbon atoms, optionally substituted; R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 represent, independently of one another, an atom or a group of atoms; (Het)aryl independently represents an aryl or heteroaryl group; and A represents an anion.

##STR00001##

The present invention provides a method for determining a background count rate in liquid scintillation counting. The method comprises measuring external standard spectra of a sample, determining, from the external standard spectra, a triple to double coincidence ratio and a quench parameter, determining, based on the triple to double coincidence ratio and the quench parameter, a background reference parameter, and determining, based on the background reference parameter, the background count rate from a background reference curve.

Scintillation compositions comprising one or more different types of quantum dots dispersed in a polymer matrix material, the quantum dots having a core-shell structure, and optionally a neutron-capturing isotope. Hydrogels comprising the quantum dots and optional neutron-capturing isotope in a polymerized matrix are also disclosed, as are related detection systems and methods.

An apparatus and method for measuring three-dimensional radiation dose distributions with high spatial and temporal resolution using a large-volume scintillator. The scintillator converts the radiation dose distribution into a visible light distribution. The visible light is transported to one or more photo-detectors, which measure the light intensity. The light signals are processed to correct for optical artifacts, and the three-dimensional light distribution is reconstructed. The reconstructed light distribution is post-processed to convert light amplitudes to measured radiation doses. The high temporal resolution of the detector makes it possible to observe the evolution of a dynamic dose distribution as it changes over time. Integral dose distributions can be measured by summing the dose over time.

This disclosure concerns aromatic and polyaromatic eutectic mixtures and their use as liquid scintillators. The mixtures may include compounds including di-tert-butyl-benzenes, biphenyls and terphenyls, polycyclic aromatic hydrocarbons selected from naphthalenes, acenaphthenes, anthracenes and pyrenes, fluorenes and carbazoles, 2,5-Diphenyloxazoles, and compounds of formula (I).