Future Long-Baseline Neutrino Facilities and Detectors

Table 6

Detector parameters of the baseline design.

Detector type		Ring-imaging water Cherenkov detector
	Address	Tochibora mine
		Kamioka town, Gifu, Japan
	Lat.	36^∘21′08.928′′N
	Long.	137^∘18′49.688′′E
Candidate site	Alt.	508 m
	Overburden	648 m rock (1,750 m water equivalent)
	Cosmic ray muon flux	1.0~2.3 × 10^−6 sec^−1 cm^−2
	Off-axis angle for the J-PARC 𝜈	2.5^∘ (same as Super-Kamiokande)
	Distance from the J-PARC	295 km (same as Super-Kamiokande)
	Total volume	0.99 megaton
Detector geometry	Inner volume (fiducial volume)	0.74 (0.56) megaton
	Outer volume	0.2 megaton
	Inner detector	99,000 20 inch 𝜙 PMTs
Photomultiplier tubes		20% photocoverage
	Outer detector	25,000 8 inch 𝜙 PMTs
Water quality	Light attenuation length	>100 m at 400 nm
	Rn concentration	<1 mBq/m^3