Previous   |    Next

doi:10.2204/iodp.proc.303306.114.2006

Instrumentation

The instrumentation in Hole U1315A consists of two pressure cases and a thermistor string. The top pressure case houses salinity and temperature sensors exposed to bottom water and designed to monitor variations in bottom water. The sampling rate is set at a 30 min interval based on battery constraints and should have battery power for the 5 y expected life of the experiment. The bottom pressure case houses the data logger connected to 150 m of armored cable with 24 thermistors. The spacing between thermistors increases downhole to take advantage of natural diffusion length scales. Thermistors are calibrated to better than 1 mK. Power to this data logger is supplied with both internal batteries and external batteries. Data are collected every hour, again based on expected battery life and the 5 y life of the experiment.

Data are recorded internally with 24-bit resolution to solid-state memory. Thermistors have a resolution of <5 × 10^–5°C. Thermistors are calibrated using National Institute of Standards and Technology traceable reference standards. Typical thermistor uncertainties are <0.2 mK.

Top of page   |    Previous   |    Next