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

1.卡斯卡反应堆中微子振荡实验中含Gd浓度为0.1%的液体闪烁体的老化实验由BC521(一种含Gd浓度为0.5%的商用液体闪烁体)、PC(假异丙苯)和TD(十四烷)组成。它们保存在20℃、30℃和40℃的恒温箱中，用于加速老化试验，并每月用康普顿散射法测量它们的γ射线闪烁。三种液体分别为：BC521：PC TD=(1)20V%：20V%：60V%(2)30V%：10V%：60V%(3)20V%：10V%：70V%(V%表示体积百分比)。)450天后，三种液体均未发现变质现象。因此，它们都是卡斯卡反应堆中微子振荡实验中Gd浓度为0.1%时很好的候选液体闪烁体。用于Joyo快堆中微子探测实验的液体闪烁体衰减长度的测量自2006年10月以来，在距Joyo快堆堆芯25m处进行了一项中微子探测实验。液体闪烁体的组成为：20V%的PC，76.5V%的对羟基苯酚，3.6g/L的聚苯醚，0.053g/L的双氧水和10V的BC521。利用宇宙线介子测量了液体闪烁体的衰减长度。它的长度为930(+3400，-410)厘米，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