Neutron probes

Description

Two neutron probes were used to measure profiles of snow density from which accumulation and densification rates can be determined.

The procedure involved either auguring a 5 cm diameter access hole to a depth of approximately 12 metres or, using the 13 cm boreholes that were produced by the ice coring (see 'Deep Cores').

Once in position in the hole, the probes were slowly raised up to the surface by a cable and winch system. Signals from the probe travel up the cable to a logger and were recorded on a computer. The profiling speed was approximately 3m per hour. Neutron probe measurements were taken at each location along the traverse. Each probe contains an Americium 241 Beryllium sealed source of 1.85GBq.

References

1. iSTAR - Return to the icy wilderness

2. iSTAR - drilling into history

Field photo

iSTAR team auguring a hole in the ice in preparation for neutron probe measurement of ice density. Alex Taylor, BAS