Structure Diagram for MPC: Multiphoton Correction ================================================= An Introduction to the Structure Diagrams is available. NB These links will be broken until the HTML Version of the Code is installed. Introduction ------------ The Multi Photon Correction (or Multiphoton PCA is a SNOMAN processor used to measure the timing walk due to the multiphoton effect. The transit time spread of SNO's PMTs is about 1.5ns, and is measured by the regular PCA. If two photons strike a PMT simultaneously it is likely that one of them will arrive at the first dynode earlier than the other. The pulse from the first photoelectron will typically fire the discriminator, so tubes hit by multiple photons appear to have been hit earlier than tubes hit by a single photon. The MPC processor measures this timing shift as a function of charge, and the CAL processor uses this information to calibrate PMT times for high energy events. Titles Banks Used ----------------- TMPC Multiphoton PCA: Control MPCA Multiphoton PCA walk correction PCAS PCA Summary Initialisation Routines ----------------------- MPC_INI Execution Routines ------------------ MPC_EXE Termination Routines -------------------- MPC_TRM