The D0 Run II Luminosity Monitor

Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any speciic commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reeect those of the United States Government or any agency thereof. Distribution Approved for public release; further dissemination unlimited. Government and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government Purposes. The DD Run II Luminosity Monitor consists of plastic scintillation detectors with ne-mesh photomultiplier readout that cover the range 2.7 < jj < 4.4 in pseudorapidity. The detector is designed to provide a precise measurement of the rate for non-diiractive inelastic collisions that is used to calculate the Tevatron luminosity at DD. Excellent time-of-ight resolution allows a clean separation between beam-beam interactions and the principal background from beam halo. In addition, timing is used to measure the position of the primary interaction vertex and to detect multiple interactions. Accurate correction for multiple proton-antiproton interactions in a single beam crossing is essential for an accurate luminosity determination. Associated electronics provide a single-interaction trigger term for the DD Level 1 trigger, and readout of the photomultiplier timing and pulse-height measurements.