CMS Level 1 Calorimeter Trigger Performance on Technical Proposal Physics
We examine the eeciency and rates of the CMS Calorimeter Level 1 Trigger as presented in the CMS Technical Proposal for selecting the events needed for use in the CMS physics program described in the Proposal. Speciic signals investigated include top decays to electrons, Standard Model Higgs decays to electrons and photons, signals from SUSY Higgs, and Gluino production. A variety of masses and SUSY parameters are investigated. The eeciencies are studied at the luminosity 10 33 cm ?2 s ?1 or 10 34 cm ?2 s ?1 depending on the expected rate of events as assumed in the CMS Technical proposal. A single set of Level 1 Calorimeter energy thresholds for electrons, jets and missing energy is selected to provide a 15 kHz rate at each of the two luminosity settings considered. It is shown that this set of cuts provides suuciently high eeciency and satisses CMS physics goals as stated in the Technical Proposal. We also explore the rate of B Physics signals that pass this high p t trigger.
Cms Level 1 Calorimeter Trigger Performance Studies
The level 1 calorimeter trigger system for the CMS detector at the LHC collider must provide a deadtimeless, pipelined trigger that implements simple algorithms which satisfy the physics eeciency and data rate requirements. In this note we examine the performance of a conceptual design and that of an alternate algorithm for the electron trigger. The algorithms account for energy sharing between neighboring towers and perform hadronic, and optionally, electromagnetic isolation. Through extensive simulation of the level 1 calorimeter trigger, we have determined the background rates and eeciencies of triggers for electrons, photons and jets.
rPET detectors design and data processing
Small animal PET systems based on rotating planar detectors posses some interesting advantages for high sensitivity, high resolution imaging. We have designed the rPET detectors based on MLS crystals assembled on a 30times30 matrix optically coupled to a flat-panel PS-PMT. Weighted position readout circuits pre-process the 64 signals from the 8times8 anodes matrix, which are digitized using a charge-integrating converter. The amplification electronics, including the trigger output for coincidence detection, and the high voltage supply are integrated in a three PCBs stack that forms the base attached to the back of the PMT. The whole assembly is enclosed in a light tight, lead (Pb) shielded aluminum box. The detectors are mounted on a rotating gantry with more than 180 degrees rotation span. The digitized events are screened and histogramed, and a modified center of gravity algorithm removes from the position calculation those signals with poor signal to noise ratio. Apparent mean crystal size on the 511 keV field-flood images is 0.6 mm, mean peak-to-valley ratio is better than 8, and intrinsic resolution is 1.5 mm at the central row, with the energy window wide open. Sensitivity (CPS) for a pair of these detectors set in coincidence at 160 mm distance is 1%