The neutron-neutron (n-n) scattering length is a fundamental parameter in nuclear physics; however, measurements are plagued with large uncertainties caused by neutron detector cross talk. Many experimentalists also rely upon computer code to calibrate their neutron detectors. Experiments give one of two different numbers but there is still no adequate explanation for this discrepancy. We have developed a new neutron detector expressly for the purpose of improving the n-n scattering length measurement. It offers two important advantages: 1) minimal cross talk and 2) high counting efficiency. We calibrated the detector from 1 MeV to 6 MeV at 1 MeV increments. We have shown that the computer code, MCNP, does not always give the correct detector efficiency, and that reliance upon this code for calibration could be a large factor for error in previous experiments. Preliminary tests show no cross talk between two like detectors and suggest that these detectors in a n-n scattering length measurement.