Research of a new liquid scintillator with Gd for the KASKA reactor neutrino oscillation experiment

1. KASKA反应堆中微子振荡实验中Gd浓度为0.1%的液体闪烁剂的老化试验用商业化的Gd浓度为0.5%的液体闪烁剂BC 521、拟三甲苯（PC）和十四烷（TD）配制了三种液体闪烁剂。将它们分别置于20℃、30℃和40℃恒温箱中进行加速老化试验，每月用Co ~（60）γ射线康普顿散射法测定其结晶度。BC 521：PC TD =（1）20v%：20v%：60v%（2）30v%：10v%：60v%（3）20v%：10v%：70v%（v%为体积百分比）。3种液体在450天后无变质现象。因此，它们都是用于KASKA堆中微子振荡实验的Gd浓度为0.1%的良好候选液体稀释剂. 2006年10月，在距Joyo快堆堆芯25 m处进行了中微子探测实验。液体闪烁体的组分为20v%的PC、76.5v%的paraol、3.6g/l的PPO、0.053g/l的bis-MSB和10v%的BC 521。使用宇宙射线μ子测量液体闪烁体的衰减长度。930（+3400，-410）cm，足以实现Joyo快堆的中微子探测实验

1. Aging test of liquid scintillators with Gd concentration of 0.1% for the KASKA reactor neutrino oscillation experimentThree kinds of liquid scintillators were formulated by mixing BC521 ( a commercial liquid scintillator with Gd concentration of 0.5% ), PC (Pseudocumene ) and TD ( Tetradecane ). They are preserved in incubators temperatures of which are 20℃, 30℃ and 40℃ for accelerated test of aging, and are measured their scintillations by Compton scattering of γ ray from Co60 every month. The three kinds of liquid are following,BC521 : PC TD = (1) 20v% : 20v% : 60v% (2) 30v% : 10v% : 60v% (3) 20v% : 10v% : 70v%( v% means % in volume. )No deterioration of the three kinds of liquid was found after 450days. Therefore, all of them are good candidate liquid scintillators with Gd concentration of 0.1% for the KASKA reactor neutrino oscillation experiment.2. Measurement of attenuation length of a liquid scintillator used in a neutrino detection experiment in Joyo fast reactorA neutrino detection experiment has been carrying out at 25m point from the core of Joyo fast reactor since October 2006. Components of the liquid scintillator are 20v% of PC, 76.5v% of paraol, 3.6g/l of PPO, 0.053g/l of bis-MSB and 10v% of BC521. An attenuation length of the liquid scintillator was measured using cosmic ray muons. It is 930 (+3400, -410 ) cm which is long enough to achieve the neutrino detection experiment in Joyo fast reactor