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Minos Detector Experience in brief

Minos Detector Experience in brief. The Minos Context Detector Essentials & Elements Assembly, installation, maintenance Event reconstruction, resolutions, profiles Finer grained calorimeter. Geoff Pearce, RAL NF detector technology discussions I.C. May 7, 2005. Minos - context.

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Minos Detector Experience in brief

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  1. Minos Detector Experiencein brief • The Minos Context • Detector Essentials & Elements • Assembly, installation, maintenance • Event reconstruction, resolutions, profiles • Finer grained calorimeter Geoff Pearce, RAL NF detector technology discussions I.C. May 7, 2005

  2. Minos - context • High intensity νμ beam from Fermilab to Soudan (Mn) • Two detectors, Near (1kT) and Far (5.4kT) • Primary measurement : Compare ν energy spectrum in the Far Detector to the un-oscillated expectation from the Beam and Near Detector • Observe oscillation minimum • Confirm oscillatory behaviour in νμ sector • Measure Δm232 to ~10% • Look for νμ→ νe oscillations, measure θ13? Baseline : 730km 1kton near detector 5.4kton far detector

  3. _ Both νµ and νµ beams Minos – Energy Regime Nominal Beam Configurations 120GeV M.I. protons, graphite target 2.5 1013 / 8.67 µs pulse, 1.9s rep. rate (.25MW) Beam energy can be tuned by adjusting position of 2nd horn relative to target Energy regime ~ 1 – 25 GeV Δm2 expectation dropped considerably since conception/design LE beam best match for Δm2 ~ 2-3 10-3 eV2at the Minos baseline Lower energy than NF, but not too disimilar

  4. Veto Shield The completed Minos Far Detector Coil MINOS Far DetectorEssential features • 5.4 kton magnetised tracking calorimeter, B ~1.5T • 484 steel/scintillator planes built in 2 supermodules • 2.54cm thick steel, 192 4x1cm scint. strips per plane • orthogonal orientation on alternate planes – U,V • optical fibre readout • Veto shield covers top/sides for atmospheric v • Multi-pixel (M16) PMTs read out with VA electronics • 8-fold optical multiplexing • chips individually digitised, sparsified & read out when dynode above a threshold • excellent time resolution – 1.56ns timestamps • Continuous untriggered readout of whole detector • Interspersed light injection (LI) for calibration • Software triggering in DAQ PCs (independent of ND) • highly flexible : plane, energy, LI triggers in use • spill times sent from FNAL to FD trigger farm • GPS time-stamping to synch FD data to ND/Beam

  5. U U U U V V V V steel scintillator orthogonal orientations of strips Detector Elements Scintillator strips in light-tight modules, 8/plane 192 scintillator strips on each plane Steel scintillator sandwich 25.4mm steel, 1cm scintillator Alternate planes have orthogonal strip orientations (U,V) • Fibres carry light to MAPMTs • M16 (FD) M64 (ND) • Optical multiplexing in FD • 8 fibres per pixel 4.1cm x 1cm extruded polystyrene strips TiO2 reflective coating Groove for 1.2mm WLS fiber to collect light M16

  6. Module Assembly & Testing Design lends itself well to parallel construction Matches many University workshop capabilities Multiple factories for scintillator planes used by Minos Division of labour – construction speed Cost ~ $600 / module These can be important considerations Gluing WLS fibers Placing Scintillator strips in light case

  7. Detector assembly and Mounting • FD most challenging • Remote (Soudan, Mn) • narrow mine shaft • taken down in pieces and assembled underground • ND planes assembled above ground • Both detectors installed to schedule Installation / maintenance at remote location highly successful

  8. MINOS Near DetectorEssential features Same basic design as Far Detector Minos Near Detector as installation neared completion • 1 kton (total mass) magnetised tracking calorimeter • Partially instrumented • 282 steel planes, 153 scintillator planes • reduced sampling in rear planes (121-281) “spectrometer section” used for muon tracking • High instantaneousν rate, ~ 20ev/spill in LE beam • No multiplexing except in spectrometer region (4x) • Fast “QIE” electronics • continuous digitisation on all channels during spill • (19ns time-slicing). Mode enabled by spill signal. • dynode triggered digitisation out of spill (cosmics) • GPS time-stamping / Software triggering in DAQ • all in spill hits written out by DAQ • standard cosmics triggers out of spill

  9. m n ‘u’ - view m ghost hits due to multiplexing n m ‘v’ - view m strip # plane # Event Reconstruction Strip readout provides two 2D views (U,V) – combine to get 3D hits Resolution ~ strip width (angular resoln. on moon shadow <0.5deg) Multiplexing at FD complicates reconstruction, but soluble. MC event – zoomed in

  10. (Real) Far Detector Beam Event νµ

  11. Near Detector Eventsspecial needs One spill in Medium Energy Beam Intensity = 2.5 1013 pps Multiple events in detector Events resolved using timing ND readout has 19ns bucket resolution Near Detector must be able to cope with high rate

  12. UZ B VZ time PEs Magnetic Field • 1.5T magnetic field in steel generated by coil • Momentum measurement • Charge separation Δpµ/pµ = 10% (curvature) Δpµ/pµ = 6% (range – if available) Good knowledge of field vital Far Detector cosmic muon (courtesy MT) Stopping muon Prange = 3.86 GeV/c Pcurvature = 4.03 GeV/c

  13. Calibration DetectorThe 3rd major Minos detector • Vital to understand energy response to reconstruct Eν • Eν = pµ + Ehad • Minos design ports very well to test beam studies • Can study detector issues vital to physics • Minos built a 1m x 1m x 3.7m “mini-Minos and ran in CERN test beams to • study response to π, µ, e, p • test MC simulation • look at near / far detector differences • energy scale calibration

  14. CalDet : sample events at 2 GeV TOF/Cerenkov system at CalDet provides pure samples Colour scale = MIPs Energy distribution profile used to identify pid in Minos M. Kordosky

  15. MC expectation Minos Calibration DetectorResponse to π, p, e Preliminary Energy Resolution CalDet analysis nearing completion. Publications in preparation

  16. UZ NC Event nm CC Event n • often • diffuse VZ • m track • +hadronic • activity NC Event ne CC Event • can mimic • nm , ne • compact • shower • typical EM • shower • profile MINOS Event Profiles MCARLO νe / NC challenging but do-able at low energies.

  17. Built for NDK, ~ 1Gev 1.6mm thin steel (Minos has 25.4mm steel)

  18. Soudan2 events High resolution Bubble chamber quality 410 MeV electron shower Gaps from γ propogation Steel thickness can be tuned to needs -- and wallet

  19. Summary and Conclusions • Modular, simple, low risk, safe, not expensive • Magnet field can be applied over whole steel volume • Momentum measurement • charge ID • You get iron. • Sampling frequency, steel thickness can be chosen to match physics requirements • Active components would be chosen to optimise cost/performance • Scintillator (eg liquid, like Nova) • Photodetectors (eg MA256, HPD, etc) • Electronics, DAQ would clearly be chosen from technology of the day • Near detector can be same technology • Minos style detector is an option worth consideration

  20. Soudan events High energy event fast exiting muon two interacting pions

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