Integration of Forward Detectors, ZDC, and CASTOR into CMS Experiments Kevin Reynolds Michael Murray, Mentor 2006 Michigan REU at CERN

Primary Goals for This Project 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

Acronyms CERN-European (Council) Organization for Nuclear Research CMS-compact muon solenoid ATLAS-a toroidal LHC apparatus ALICE-a large ion collider experiment LHCb-LHC-beauty LEP-large electron positron collider PSB-proton synchrotron booster PS-proton synchrotron SPS-super proton synchrotron TOTEM-total cross section, elastic scattering and diffraction dissociation ZDC- zero degree calorimeter CASTOR-CERN Advanced Storage Manager QIE-charge integrator and encoder ECAL- electromagnetic calorimeter HCAL- hadronic calorimeter PMT-photomultiplier tube DCS- detector control system MTCC- magnet test cosmic challenge UXC- experimental underground crossing RHIC-relativistic heavy ion collider (BNL) RPC- resistive plate chamber YB- yolk barrel USLB- optical serial link board HB- hadronic barrel I & C-integration and calibration ME-muon endcap HE-hadron endcap TOF-time of flight ADC-analog digital converter DAQ-data acquisition HI-heavy ion HIROOT-generator level simulation package for heavy ions QCD-quantum chromodynamics VCAL/HF-very forward calorimeter GUT-grand unified theory USC- underground service cavern TAN-neutral particle absorber

Where We Fit into the Bigger Picture… CMS ALICE ATLAS LHCb PS SPS LHC Pb P PSB Synchrotron Injector Tunnels Experimental Station

Interesting Facts About CERN Dan Brown uses the following statement to describe CERN in his book Angels and Demons which is also staged at CERN. “Atoms look like planets compared to what we deal with. Our interest’s lie with an atom’s nucleus- a mere ten-thousandth the size of the whole. The men and women of CERN are here to find answers to the same questions man has been asking since the beginning of time. Where did we come from? What are we made of?” The circumference of the LHC is ~27 km, and the facility sits on the border between France and Switzerland. Nearly 3000 particle physicists are employed full time at CERN, nearly half of the world’s particle physicists community. (Wikipedia)(Wikipedia) Two linear accelerators, Linac 2 (P-for protons) and Linac 3 (Pb for heavy ions), inject the particles into the smallest of three booster rings, the Proton Synchrotron Booster (PSB). This feeds directly into the Proton Synchrotron (PS) which ramps the particles to energies around 28 GeV. From there, the particles enter into the more powerful Super Proton Synchrotron (SPS) where energies of ~450 GeV are reached. In 2007, the SPS will feed protons and heavy ions into the Large Hadron Collider (LHC) expected to achieve ~14 TeV in proton-proton collisions. The total estimated cost for the building of CERN is US $8 billion. (Wikipedia)(Wikipedia)

Cross Section of CMS

Compact Muon Solenoid

The inner core of the detector contains the silicon microstrip tracker made to detect high momentum muons, isolated electrons, and hadrons. This part of the detector has been optimized in an attempt to locate the Higg’s boson. The next layer is the electromagnetic calorimeter (ECAL) which detects the presence of particles which interact via the electromagnetic force and take a relatively short time to decay. Examples are the electron and photon. The layer surrounding the ECAL is the hadronic calorimeter (HCAL) which detects particles which interact via the strong force and take longer to decay. Examples are neutrons, pions, neutrinos, quarks, and gluons. A superconducting solenoid magnet surrounds these detectors and forms concentric layers with muon detectors known as scintillators and interleaved magnetic iron yolk plates. (CMS Homepage)(CMS Homepage) Interesting Facts About CMS

Integration of the Zero Degree Calorimeter The main components for the detector should be received at CERN by mid July 2006 Beam tests begin the first week of August ZDC2 INTERACTION POINT ZDC1

Testing Muon Scintillators A scintillator is a commonly used detector for high-energy ionizing electromagnetic or charged particle radiation. They can either be organic or inorganic. The ones we used were organic and made out of plastic. When electrons, or other charged particles are incident on the surface, photons are produced through this interaction, and they are captured by the plastic sheets. The sheets serve as waveguides which lead to the PMT (photomultiplier tube). A photomultiplier tube is a device characterized by a high voltage being applied across a vacuum chamber such that electrons ejected from a photoelectric metal via incident photons collide with dynode material. Secondary showers of electrons referred to as avalanches, leave the region to represent the initial number of photons incident. The cascade serves an an amplified signal which can be readout in a digital format through an ADC (analog digital converter).

In a coaxial cable, the positive lead wire is coated with a layer of plastic to insulate, and the negative/ground cable is the outmost layer. In the Fourier series structure consisting of a constant term and sine and cosine terms, the constant term corresponds to a DC signal whereas the trignometric terms correspond to AC. Impedances of cables and the electronic device must be matched so that reflections of signal are minimized. Optic reflections in mediums of differring indexes of refraction are very similar in nature. A discriminator for an electronic device sets a minimum voltage quantity (noise) that must be reached in order to trigger a response, such as the start of a counter. When a voltmeter/multimeter is short-circuited, a readout of zero volts can be used as an initial calibration check. Electronics Notes

Preparation for Beam Tests The upper part of the beamline sensitive to Cherenkov raditation was disassembled and the lens checked for contaminants. The photomultipler tube was then reassembled, vacuumed down, and refilled with freon gas. The pressure for the tube held over night, a good indication that the chamber was hermetically sealed. ( ) Beamline Wire Chambers Scintillators Cherenkov detector 6

Electronic Layout Before the parts for the ZDC are received in July for installation, system checks are being made with the wire chambers and scintillators at the test area. 8

Cherenkov radiation is emitted when high-energy particles travel faster than light in certain mediums other than vaccum. Atoms in the medium become excited and give off their energy with short fluorescent decay. The radiation is emitted in a narrow cone, similar to a sonic boom in air. In our experiments, a mirror collects the radiation which usually is emitted in blue to near ultraviolet ( nm). The shift of wavelength is known as the Stokes-shift. The Cherenkov light is emitted under a constant angle given by cos θ = v t / v = c/ (vn) = 1/ (βn). Cherenkov Radiation Sonic Boom 7