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

1. 以Gd浓度为0.5%的商用液体闪烁体BC521、PC（伪芳烃）和TD（十四烷）为原料，配制了三种不同浓度的液体闪烁体。分别在20℃、30℃和40℃的培养箱中进行加速老化试验，每月用Co60 γ射线康普顿散射法测量其闪烁度。三种液体如下，BC521: PC TD = (1) 20v%: 20v%: 60v% (2) 30v%: 10v%: 60v% (3) 20v%: 10v%: 70v%（v%表示体积%）450d后三种液体均未见变质现象。因此，它们都是Gd浓度为0.1%的KASKA反应堆中微子振荡实验的良好候选液体闪烁体。自2006年10月以来，在距卓悠快堆堆芯25m处进行了一项中微子探测实验。液体闪烁体的组成为PC 20v%， paraol 76.5v%, PPO 3.6g/l, bis-MSB 0.053g/l, BC521 10v%。利用宇宙射线μ子测量了液体闪烁体的衰减长度。它的长度为930 (+3400,-410)cm，足以在卓悠快堆中实现中微子探测实验

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