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The MoEDAL Experiment: A Progress Report

The MoEDAL Experiment: A Progress Report. LHCb. MOEDAL. James Pinfold (for the MoEDAL Collaboration). The MoEDAL Collaboration.

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The MoEDAL Experiment: A Progress Report

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  1. The MoEDAL Experiment: A Progress Report LHCb MOEDAL James Pinfold (for the MoEDAL Collaboration) James L. Pinfold LHCC Report February 2005

  2. The MoEDAL Collaboration CSR, University of Alberta, Edmonton, Alberta T6G OV1, CANADA: B. Caron, J. de Jong, J. L. Pinfold, J. Soukup, W. J. McDonald, Y. Yao. Main responsibility: Mechanical design/construction, calibration of plastic and Monte Carlo, IoP, University of Bologna, Via Irnerio 46, Bologna, Italy: G. Giacomelli, H. Dekhissi, A. Margiotta, L. Patrizii, P. Serra, M. Spurio Main Responsibility: Preparation, etching & measurement of plastic and (soon) Monte Carlo CERN, Geneve 23, Switzerland: M. Placidi Main responsibility: Issues to do with the beam Dept. of Physics, University of Cincinnati, Ohio, USA: K. Kinoshita Main Responsibility: Preparation, etching & measurement of plastic Lab. de Physique Nucleaire, Universite de Montreal, Succ. "A", Montreal, Quebec H3C 3J7, Canada: A. Houdayer, C. Leroy Main responsibility: radiation damage effects, calibration of plastic Dept. of Physics, Northeastern University, 112 Dana, Boston, US: J. Swain Main responsibility: Monopole energy loss considerations James L. Pinfold LHCC Report February 2005

  3. Introduction • Radiation tolerance of the MoEDAL • Studying the material budget in the LHCb VELO region • A GEANT4 simulation of the monopole in the framework of the LHCb simulation program (GAUSS) • A preliminary idea of the sensitivity of the MoEDAL monopole search • Moving towards the final design of MoEDAL detector • Estimating backgrounds from spallation products • Monitoring MoEDAL performance • Moving towards the Technical Proposal • Some Post TP Considerations James L. Pinfold LHCC Report February 2005

  4. A Very Brief Review of Monopole Properties • Quantized magnetic charge: ge=nħc/2 • The magnetic charge is: g = ngD = nħc/2e = n68.5e (n=1,2,3…) • Magnetic coupling constant: g2/hc= 34.25n2 • Energy gain in a magnetic field: dE/dx=gB=0.2n2 (GeV/cm)B(Tesla) • Ionization (for b>10-3): • Ionization goes up by 4, 9, 16…depending on whether n=2, 3, 4… • Mass…not predicted by Dirac • Various theories give Monopole solutions with a range of masses – assume mass is a free parameter James L. Pinfold LHCC Report February 2005

  5. Brief Review of MOEDAL Detection Technique Look for aligned etch pits In multiple sheets • The passage of a highly ionizing particle through the track-etch detector is marked by an invisible damage zone along the trajectory. • The damage zone is revealed as a cone shaped etch-pit when the plastic detector is etched in a controlled manner using a hot sodium hydroxide solution. • The depth of the etch pit is an increasing function of the particle Z/b • This is a well studied, simple, easy to calibrate and cost effective technique James L. Pinfold LHCC Report February 2005

  6. Other Possible Physics Aims hep-ph/9707376 • Dyons – particles with electric & magnetic charge • Massive (quasi) stable exotic particles (Colour sextet quarks, SUSY MSE particles, etc.) • Massive (quasi) stable multiply charged particles (eg H++ from L-R symmetric models) • Q-ball type objects (aggregates of squarks , sleptons, Higgs fields) • ETC. James L. Pinfold LHCC Report February 2005

  7. Radiation Environment Around VELODose James L. Pinfold LHCC Report February 2005

  8. Hadron Fluxes ~1010 hadrons /cm2 each year ~1011 neutrons/cm2 each year Neutron flux, x=0 Charged hadron flux x=0 James L. Pinfold LHCC Report February 2005

  9. Radiation Resistance of CR39/Lexan • Results obtained from an expt. at the D0 intersection regions at FNAL • Phys. Rev. Lett. 59, p2523, 1987. • Chemistry of rad. sensitivity of CR-39 polymers has been studied • J. Electrochem. Soc., p811, 1982. • Track etch detectors can have the following radiation tolerance • CR39 2MRads - Rodyne(lexan) 200 Mrad - UG-5 glass 1000 Mrads. • Radiation level at LHCb – 1.4 m from the IP is low enough to deploy CR39 for several years without problems. We expect to change plastic 12 times per year. James L. Pinfold LHCC Report February 2005

  10. Material in the VELO Region (1) + COVER 1.2 m The LHCb IP – the VELO region James L. Pinfold LHCC Report February 2005

  11. Material in the VELO Region (2) • Distribution of material in the LHCb vertex region (in radiation lengths) as described by the LHCb simulation program GAUSS. James L. Pinfold LHCC Report February 2005

  12. A GEANT-4 Simulation of the Monopole • GEANT4 simulation for the monopole prepared to work within the LHCb GAUSS simulation package (many thanks to Gloria Corti of LHCb for her assistance here) • Results cross-checked against a GEANT3 monopole simulation (CDF: Bauer et al, Submitted to Elsevier Science) and stand alone code. • This package allows us to: • Track a monopole or dyon • Simulate ionization energy loss • Simulate multiple scattering • If produced inside a particle detectors a monopole or dyon would be revealed by its unique characteristics: • Monopoles would accelerate along magnetic field line • Monopole would have extremely high ionization compared to charged particles. James L. Pinfold LHCC Report February 2005

  13. Tracking • Electric-magnetic duality of ME gives a generalized Lorentz force for particles carrying arbitrary electric charge e and magnetic charge g: • This describes the motion of a dyon, setting electric charge to zero gives a differential equation describing the motion of a monopole in a magnetic field. • Qualitatively the monopole in a magnetic field behaves like an electron in an electric field. James L. Pinfold LHCC Report February 2005

  14. An Example of Monopole Pair Production in MOEDAL/LHCb MOEDAL The other monopole hits the pole face of the LHCb dipole magnet One monopole Hits MOEDAL James L. Pinfold LHCC Report February 2005

  15. Energy loss • The net effect is to replace ze by ngb in the Bethe Bloch formula: • Similarly the mutiple scattering of a monopole has the factor of ze replaced by ngb Monopole energy loss increases with velocity A highly relativistic monopole ionizes up to 4700 times more than that of a proton James L. Pinfold LHCC Report February 2005

  16. Monopole Pair Production • On average the acceptance of monopole pairs (in which at least one of the monopole is detected) is ~80% over most of the detectable monopole mass range (assume pairs produced isotropically in the centre-of-mass system) • Acceptance of monopole detector plastic covering both pole faces of the LHCb dipole magnet is approximately a factor of 10 smaller that that of MOEDAL over most of the detectable mass range Acceptance for a single monopole Isotropically produced. James L. Pinfold LHCC Report February 2005

  17. Limits After a Year at 2 x 1032 cm-2 s-1 Preliminary MOEDAL (95% CL) James L. Pinfold LHCC Report February 2005

  18. Estimating Backgrounds with GEANT4 • Backgrounds due to spallation products in the detector and environs – etch pits from hadronic backgrounds. • We are using GEANT4 to provide extra detailed information on the size of the potential background. • It is expected that backgrounds will be extremely small due to the uniquess of a monopole signal (>3 precisely aligned pairs of etch pits, consistent with a monopole charge, pointing to the IP within ~1 cm) • Use Geant4 Hadronic Physics lists: http://cmsdoc.cern.ch/~hpw/GHAD/HomePage/In particular: • High energy calorimetry (for spallation products produced by high energy particles from interactions) • Low energy dosimetry (to look at neutron produced damage) • The high energy calorimetry code uses:“The second physics list, QGSP -- theory driven modeling for the reactions of energetic pions, kaons, and nucleons. It employs quark gluon string model for the 'punch-through' interactions of the projectile with a nucleus, the string excitation cross-sections being calculated in quasi-eikonal approximation. A pre-equilibrium decay model with an extensive evaporation phase to model the behavior of the nucleus 'after the punch'. It uses current best pion cross-section.” • Initial estimates indicate that the background from this source is negligible – we are currently working on final numbers for this background level. James L. Pinfold LHCC Report February 2005

  19. The Conceptual Design of MOEDAL • In June of 2001 the LHCb collaboration completed the LHCb “VELO” (VErtex Locator) TDR that incorporated the latest LHCb vertex region design. • We have been tracking developments in the VELO region since that time. • The LHCb vertex region design is now reasonably mature Thus we have begun the design of the final MOEDAL detector. • This design presented here is conceptual only and must be refined in consultation with the LHCb collaboration and CERN TIS group. • Thus we expect this design to evolve. • Obviously the LHCb collaboration must be completely happy with the final product which must also satisfy CERN safety criteria,. James L. Pinfold LHCC Report February 2005

  20. The Conceptual Design of MOEDAL(1) Support from roof only in initial design Radius of sphere 1.4m Detector is a housed in geodisic segments. To allow fast access (within an hour) to VELO. The detector opens lake a “ladybird’s wings”. James L. Pinfold LHCC Report February 2005

  21. The Conceptual Design of MOEDAL(2) • Light aluminium frame containing five plastic sheets per triangle element (Lexan-CR39-Lexan-CR39-CR39-lexan). Total thickness ~ 5 mm. • Alignment of monopole track within the module ~10 microns (using dowel pins) • All triangular elements do NOT have to be installed. The design allows for access “panels” to LHCB vertex vacuum region. • Frame holds plastic so that tracks are as normal as possible to the plastic, and racks reconstructed can be pointed to the interaction point two within ~1 cm James L. Pinfold LHCC Report February 2005

  22. Monitoring MOEDAL Performance • We have devised a procedure to check that the experiment is working – particularly in the high radiation environments of the LHC • We propose to irradiate small areas of the CR39 detectors with ions prior to deployment. • For example we would use: • Relativistic Fe ions for CR-39 (Z/b ~30) • Gold ions for Rodyne/lexan (Z/b ~90) • Only if these “fake” monopole tracks in individual sheets give detectable holes with the “ammonia technique” after etching will the detector be deemed to be working. James L. Pinfold LHCC Report February 2005

  23. Towards the Technical Proposal(1) • A priority for the next 6 months of ‘05 - as the VELO region design is now stable - is to work with LHCb-VELO region engineers to modify mounting scheme of MOEDAL to be compatible with LHCb, specifically: • There should be no mechanical contact with the VELO vessel • The MoEDAL detector should be able to be moved within a few hours at most to allow quick access to the VELO region • The MoEDAL detector should be moveable completely within 6 hours to allow work on the VELO region where crane access is required. • Demonstrate the deployment of MOEDAL by building a model of the MoEDAL frame and deploying it around the model of the VELO region • We assume that LHCb collaboration would have to formally approve of the MoEDAL mounting scheme and operating procedure before any approval for MoEDAL can be given • The plans for the installation /staging of MoEDAL in the VELO region will also be discussed closely with LHCb, obviously this schedule must be completely compatible with LHCb plans. James L. Pinfold LHCC Report February 2005

  24. Towards the Technical Proposal (2) • Work with CERN TIS group to finalize design of MOEDAL detector (in progress). Particular areas of investigation are: • Activation: Detectors already sent to CERN for activation studies (Aluminium & plastic are not expected to be problematic) • Safety (access for fire control, flammability, etc.) • We plan to submit the MoEDAL design to CERN TIS for inspection after the MOEDAL design is stable – we expect this to be in the summer of 2005. although flammability studies (of the basic plastic detector element) can start within a month or two. • Finalize picture of the sensitivity of detectors to radiation in the LHCb region using GEANT4 equipped to study spallation products . This work is in progress and it is expected to be finished by the summer of 2005. • Perform detailed MC studies - using existing program, full detector implmentation and latest material distribution - of monopole acceptance using the now available GEANT4/GAUSS monopole simulation. The work is in progress and is expected to be completed by spring 2005. • Include studies of other physics aims such as Q-ball detection and the detection of heavily ionizing conventionally charged Exotics This work has started and will be completed by fall 2005. • Produce first version of the MOEDAL TP by the end of the 2005. James L. Pinfold LHCC Report February 2005

  25. Post TP Considerations (1) • We estimate that the cost of the MOEDAL mechanical assembly and deployment will be less than 80kCHF (re: UofA machining @ 5 CHF/hr) • The area of plastic used is estimated to be 12m2 x 5 layers (3- CR39 & 2-Lexan) costing ~20K CHF. Expect to change plastic  twice per yr. • The MoEDAL groups have established expertise and infrastructure. Eg: • The Alberta group has extensive mechanical design & construction experience (eg: machining of ATLAS HEC, design of HEC construction jigs etc.) • The Bologna Group has extensive experience with analyzing plastic and extensive etching, scanning infrastructure (eg, for MACRO & SLIM) • The Cincinnati group (KK) has extensive experience with analyzing plastic and has some etching and scanning capability (Eg KK group at Harvard analyzed MODAL & OPAL-monopole plastic, etc.) • The Alberta, Bologna & Cincinatti groups have established expertise in perfoming direct searches for monopoles at accelerators LEP (L6), LEP (OPAL), the Tevatron, KEK, etc. • The Montreal Group has extensive experience in the effects of radiation radiation damage (eg Claude Leroy was an ATLAS convenor in this area) • All the above groups have extensive experience with MC simulation/ physics analysis (Eg GEANT3/4 calculations at LEP, ATLAS, CLEO, MACRO, SLIM etc. James L. Pinfold LHCC Report February 2005

  26. Post TP Considerations (2) • Availability of main funding requirement is subject to approval of MoEDAL TP • However, a substantial amount of the infrastructure required to perform the experiment already exists • The detector is simple and completely passive. Construction is envisaged to start in 2006, and take between 8 10 months integrated time. The envelope to be determined by funding availability • The installation time required is (in principle) short (around a month). We expect that the construction schedule will be modified to meet the requirements of LHCb. • The MoEDAL is much simpler than the usual collider detector. However, there are still major challenges to face before we can see physics from it. James L. Pinfold LHCC Report February 2005

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