7. Where is the tunnel portal located?

The present location of INO portal is within the Tamil Nadu Electricity Board (TNEB) land straddled on one side by a coffee estate and the road on the other side and is at least 500 meters from the nearest forest boundary. The portal is also located next to an existing road, within the Singara housing colony, leading to PUSHEP tunnel. This is a very big advantage as no new road laying is involved. An important advantage of the site at Singara is the shortest tunnel length, 2100 meters, to reach a rock overburden of 1300 meters above the laboratory since the mountains rise steeply at this point.

The surface facilities are minimal and include bare necessities like ventilation and power systems. The laboratory will be serviced along the tunnel for all its requirements. The air-blowers situated at the entrance provide fresh air through the tunnel with its outflow being at the portal itself. The present design does not include shafts or vents at any point along the tunnel. The only opening to the surface is the portal itself.

Because the detector is a static detector, like a telescope, there is no noise from moving parts. The noise from the ventilation fans may be minimised further by locating them underground, if necessary, just inside the portal so that their operation remains quiet.