Neutrino Oscillations

Table 1

Radiopurity of the Borexino detector during phase 1 of the experiment.

Name	Source	Typical	Required	Achieved
14C	Intrinsic PC	~10^−12 g/g	~10^−18 g/g	~2 ×10^−12 g/g
238U	Dust	10^−5--10^−6 g/g	<10^−16 g/g	(5.0±0.9)×10^−18 g/g
232Th	—	—	—	(3.0±1.0)×10^−18 g/g
7Be	Cosmogenic	~3 ×10^−2 Bq/ton	<10^−6 Bq/ton	Not observed
40K	Dust, PPO	~2 ×10^−6 g/g (dust)	<10^−18 g/g	Not observed
210Po	Surface		<7 cpd/ton	May 07 : 70 cpd/ton
	Contamination	—	—	May 09 : 5 cpd/ton
222Rn	Emanation, rock	10 Bq/L (air, water)	<10 cpd/100 tons	<1 cpd/100 tons
	—	100–1000 Bq/kg (rock)	—	—
39Ar	Air, cosmogenic	17 mBq/m^3 (air)	<1 cpd/100 tons	≪^85Kr
85Kr	Air, nuclear weapons	~1 Bq/m^3 (air)	<1 cpd/100 tons	30±5 cpd/100 tons