APPENDIX B. GLOSSARY page 44
Rolling Background: This is the background accumulation method used in most of TSA’s instruments. Background accumulation is done in ten separate buffers, each buffer represents 1/10 of the total background time. As each buffer is filled, the background is updated. This results in a background update at background time/10. Initial background accumulation requires the full background time.
Standard Background: Standard background requires the full background time for the initial background and updates.
ULD: The Upper Level Discriminator provides a threshold, usually adjustable, that determines the highest signal level that will be accepted as a nuclear pulse by the system’s electronics. Also see LLD.
Model