Gadolinium has the highest thermal neutron capture cross-section of any element. The neutron capture reaction yields beta particles and several gamma rays having total energy of about 8 MeV. Delayed coincidence and pulse shape discrimination techniques can be employed.
The main applications of BC-521 and BC-525 are neutron spectrometry and neutrino research. Both are formulated with high flash point solvents because they are often used in large volumes.
BC-521 is formulated to yield the highest light output possible as well as long-term chemical stability. The standard gadolinium concentration is 0.5% by weight, but other concentrations up to 1.5% can be supplied. Since the liquid is normally used in large tanks containing several hundred liters, it employs a high flash point solvent for safety purposes.
BC-525 scintillator, with its mineral oil component, has a higher light transmission and higher flash point than traditional gadolinium-loaded liquids. It is also more suitable for use in large tanks containing acrylic plastic components. BC-525 is available with gadolinium concentrations up to 0.5% by weight.
|Gadolinium Content||0.5%, w/w|
|Light Output, %Anthracene||68||55|
|Wavelength of Maximum Emission, nm||424||425|
|Decay Time, short component, ns||3.6||3.8|
|Bulk Light Attenuation, meters||>4||>4.5|
|No. of H Atoms per cc (x1022)||5.25||6|
|No. of C Atoms per cc (x1022)||4.00||3.85|
|Ratio H:C Atoms||1.314||1.56|
|No. of Electrons per cc (x1023)||2.97||2.99|
BC-521 Gadolinium Loaded Liquid Scintillator
BC-525 Gadolinium Loaded Liquid Scintillator