Integration of Forward Detectors, ZDC, and CASTOR into CMS Experiments Kevin Reynolds Michael Murray, Mentor David d'Enterria, Co-mentor 2006 Michigan REU at CERN July 28, 2006REU Status Report II 1

Review of Project Goals Assist in the integration of forward detectors, ZDC, and CASTOR into CMS experiment Work on layout of electronics for ZDC and modification of existing CMS HF electronics to produce technical triggers for CMS global trigger Assist with beam tests of ZDC and CASTOR and the analysis of the test beam data July 28, 2006REU Status Report II 2

Integration of the Zero Degree Calorimeter ZDC2 INTERACTION POINT ZDC1 z The main components for the EM and HAD sections (tungsten, PMTs, fibers, frame, etc.) were shipped on Tuesday and Wednesday to the Previssin site Installation of parts begins this weekend Readout cables were cut earlier this week and are being delivered by CERN Beam tests on the ZDC will hopefully begin late Monday or early Tuesday of next week July 28, 2006REU Status Report II 3

Readout Unit (RU)  Unpacks data so that events can be triggered and read Data Concentrator Card (DCC)  Packs data from events Hadronic Trigger Region (HTR)  Accepts digital signal  Calculates deposited energy and time of flight  Decides which events to save Electronic Layout for ZDC PMTQIEHTRDCCCPURUZDC Photomultipler Tube (PMT)  Converts photons to electrons via photoelectric effect  Electrons drawn across HV  Cascade of electrons produced from collisions with dynodes Charge Integrator and Encoder (QIE)  Accepts analog signal (parallel)  Converts analog to digital  Sends out digitized signal through optical fibers (serial) z July 28, 2006REU Status Report II 4

Cherenkov Gases for Beam Tests Moving With Respect to Particle Stationary With Respect to Particle v>v t n>1 v>v t n>1 v θ θ v cos θ c = v t / v = c / (vn) = 1/ (βn) July 28, 2006REU Status Report II

As the refraction index of the gas is increases, the emission angle of Cherenkov radiation also increases. Index of Refraction Preparation for Beam Tests  Gases to be used in the Cherenkov detectors upstream at the H2 CMS site are N 2, CO 2, Freon, Helium, and Isobutane. Argon is used in the ZDC wire chambers. cos θ c = v t / v = c / (vn) = 1/ (βn) Stationary With Respect to Particle v>v t n>1 θ v July 28, 2006REU Status Report II 5

Electronics Notes Zero Degree Calorimeter (ZDC)-mainly concerned with measuring deposited energy of neutral particles not swept away by the first bending magnets, these include photons and neutrons ; can be used as a calibration tool for CMS, the more neutrons it receives, the lower centrality of collisions in CMS; must be radiation hard, forward physics, quartz fibers used instead of plastic or glass, large Lorentz factors of excited nuclei, high density (contracted) electric fields; similar design to the ZDC RHIC (Brookhaven) Photomultipler Tube (PMT)- photons collected by optical fibers hit photocathode which produce electrons through photoelectric effect, electrons drawn across a HV ( V) vacuum, hit dynodes which produce a cascade of electrons, are collected and read out as a current (analog signal) through an anode, 8 channels readout out Charge Integrator and Encoder (QIE)- like a ADC but converts analog signal as an exponential function rather than a linear function, better suited for analyzing over the dynamic range of TeV, read in from a clock control module which moderates and sets parameters for the timing of the QIE chips, the converted digital signal is then read out from parallel to serial data stream through fiber optic cables, analog digital converter, ideally we digitalize as early as possible to eliminate noise, optic cables send light to a photodiode Hadronic Trigger Region (HTR)- does the dynamic calculation of deposited energies and times of flight by reading in through many channels, decides which events are worth saving, 10 bits/ns, photons converted back to electons Data Concentrator Card (DCC)- packs the data into a form that can be read in through a computer terminal Readout Unit (RU)- unpacks data so that it can be read out by the computer user July 28, 2006REU Status Report II

Physics Trivia: Larger Than Life… GIVEN… The Eiffel Tower is approximately 324 meters high! ( 324 meters ≈ 354 yards QUESTION If I grew in proportion to the same height as the Eiffel Tower, how much surface area would be covered by the bottom of my shoe? My Height: 76 in Shoe Length: 13 in Shoe Width: 4.5 in ANSWER My shoe would cover a total area of 1,281 sq. yds. ~¼ total area of a football field! July 28, 2006REU Status Report II 6

Calculations 1 m ≈ 1.09 yd 354 yards ≈ 1062 ft ≈ 12,744 in Shoe Length: L / 12,744 in  13 in / 76 in Shoe Width: W / 12,744 in  4.5 in / 76 in L = 2180 in = 182 ft = 61 yd W = 755 in =63 ft= 21 yd SA for Shoe = 1281 sq. yd. SA for Field= 5400 sq. yd. July 28, 2006REU Status Report II

Acknowledgements Ford NSF University of Michigan –Dr. Homer Neal –Dr. Jean Krisch –Jeremy Herr Michael Murray, Mentor David d'Enterria, Co-mentor Staff at CERN Previssin site July 28, 2006REU Status Report II7