Determination of the light yield of organic scintillators

Scintillation properties of solution-grown trans-stilbene single crystals

“…Corrections by a factor of 1.37 determined by comparison of the spectral ranges for anthracene luminescence and spectral sensitivity of the PMT brought these ratios to 0.69 and 0.64, respectively. The relative light yield, estimated in these measurements is similar to the most reliable data reported for melt-grown crystals of different sizes (~0.6-0.7 [24,25]) and close to the theoretical estimations, from which this ratio is not expected to be higher than 0.75 [6].…”

“…There are, however, observations that indicate that the light loss could also be influenced by specific structural defects. It is known that melt-grown stilbene crystals are characterized by a mosaic structure, with varying degrees of block disorder [24], common for low-symmetry monoclinic crystals grown by the Bridgman techniques. Such blocks are not typical for solution growth that proceeds mainly by dislocation mechanisms forming more homogeneous single crystal structures.…”

Composite Scintillators Based on Organic Grains and Their Pulse Shape Discrimination Capability

“…Recalculating the data obtained in relation to the value of the light output of the reference scintillators in photons per 1 MeV, we obtain the values of the light output of the studied samples. The error of this method is less than 5% [11]. The setup was calibrated using 22 Na, 60 Co, 137 Cs, and 152 Eu gamma sources.…”

“…The optical transmission was measured using a Shimadzu UV-2450 spectrophotometer. The absolute error in determining the wavelength was 0.4 nm, and the error in measuring the spectral transmission coefficients was 0.6% [11]. An integrating sphere was used in the measurements, which made it possible to collect most of the scattered light on the photodetector of the spectrophotometer.…”

X-ray topographic study of growth defects of trans-stilbene crystals grown from solutions

“…The mechanism that involves elastic scattering of neutrons on hydrogen nuclei with production of scintillation pulses has been tested with a variety of aromatic crystals [4,5], among which single crystal trans-stilbene was found to be the best material due to its remarkable pulse shape discrimination (PSD) properties [6] not challenged so far by any other types of organic scintillators. Relatively small crystals (up to 10 cm) of transstilbene have been traditionally grown from melt by the Bridgman technique [7], but due to the high thermal expansion and low mechanical strength of these crystals, the thermal gradients and the clamping contact with the ampoule wall involved in this method lead to formation of a defective mosaic structure, with varying degrees of block disorder [8].…”