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Vyacheslav Klyukhin, SINP MSU

Vyacheslav Klyukhin, SINP MSU. New CMS Magnetic Field Map. Outlook. The CMS detector The CMS magnet TOSCA model The CMS magnet model validation Conclusions. Compact Muon Solenoid - CMS. The CMS Magnetic System.

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Vyacheslav Klyukhin, SINP MSU

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  1. Vyacheslav Klyukhin, SINP MSU New CMS Magnetic Field Map V. Klyukhin, SINP MSU / CERN

  2. Outlook • The CMS detector • The CMS magnet TOSCA model • The CMS magnet model validation • Conclusions V. Klyukhin, SINP MSU / CERN

  3. Compact Muon Solenoid- CMS V. Klyukhin, SINP MSU / CERN

  4. The CMS Magnetic System • The Compact Muon Solenoid (CMS) is a general purpose detector at the CERN Large Hadron Collider (LHC) • The CMS magnetic system consists of 4T NbTisuperconducting coil with 6 m diameter by 12.5 m long free bore and a 10000-ton yoke made of construction steel (up to 0.17% C, up to 1.22%Mn, some Si, Cr, and Cu) • The yoke includes 5 dodecagonal 3-layred barrel wheels, 4 end-cap disks at each end, 2 nose disks and comprises the ferromagnetic parts of forward hadronic calorimeter and the LHC magnets shield V. Klyukhin, SINP MSU / CERN

  5. TheCMS Transverse Sectionin the Middle Plane 12 azimuth sectors, S 2 chimneys for electrical and cryogenic leads Steel connecting brackets Tail catcher rotated by 5º w. r. t. the barrel blocks Muon chambers HCAL, ECAL, tracker Barrel feet V. Klyukhin, SINP MSU / CERN

  6. The CMS One Quarter Longitudinal Section Muon chambers Upgraded 4th disk The contribution of the yoke central part into the central magnetic flux density is 7.97%. The contribution of the forward parts and the steel floor of the underground experimental cavern is 0.03%. HF HCAL ECAL Tracker V. Klyukhin, SINP MSU / CERN

  7. The CMS Magnet Model • The continuous direct measurements of the magnetic flux density B have been performed in the inner tracker region • The continuous direct measurements of B outside the CMS coil are extremely difficult to perform • The description of B distribution in full detector volume is done with a 3-D model of the CMS magnetic system calculated with the Cobham / Vector Fields program TOSCA • The model validation is done with the 3-DHall sensor and flux loopmeasurements V. Klyukhin, SINP MSU / CERN

  8. The CMS Magnet Model with Upgraded 4th Disks V. Klyukhin, SINP MSU / CERN

  9. The CMS Magnet Model Used for Validation Chimney at W+1 5 barrel wheels, W Superconducting solenoid of 4 T 4 end-cap discs, D Outer diameter is14 m; full length of the barrel and end-cap yoke is21.61 m; the coil inner bore is6 m, the coil length is12.5 m, the operational central magnetic flux density is3.81 T. Tail catcher, TC Carts Nose disk, N Keels V. Klyukhin, SINP MSU / CERN

  10. The B-H Curves Used in the Model Barrel steel, forward parts End-cap steel V. Klyukhin, SINP MSU / CERN

  11. Magnetic Flux Distribution in the CMS Longitudinal Section Calculated with the Magnet Model V. Klyukhin, SINP MSU / CERN

  12. Magnetic Field Map Azimuth Sector Volumes V. Klyukhin, SINP MSU / CERN

  13. Magnetic Flux Distribution in the Middle Plane Calculated with the CMS Magnet Model Selected and changed to R<50 m, |Z|<60 m in the recent model V. Klyukhin, SINP MSU / CERN

  14. Magnetic Field Map of 2014 • Map is prepared in a cylinder of 18 m diameter and • 40 m long • 9600 volumes are used in the full azimuth range • The volumes boundaries correspond to field • discontinues, which are due to changes in magnetic • permeability of the materials • The volumes are grouped in 24 azimuth sectors and • searching is made for 400 volumes in the needed • sector • Cashing mechanism reduces the CPU time of searching • B in a given point is found by linear interpolation • between the values on a regular grid • The necessary tables of B are prepared with the • OPERA-3d Post-Processor tool using scripts V. Klyukhin, SINP MSU / CERN

  15. Calculated (2014) Magnetic Flux Density Bx-component in the vertical plane at B0=3.81 T V. Klyukhin, SINP MSU / CERN

  16. Calculated (2014) Magnetic Flux Density By-component in the horizontal plane at B0=3.81 T V. Klyukhin, SINP MSU / CERN

  17. The CMS Inner Field Measuring NMR-probe In 2006 during the MTCC the magnetic field was measured with a fieldmapper designed and produced at Fermilab inside a cylinder of 1.724 m radius and 7 mlength at 5 central field values: 2, 3, 3.5, 3.8, and 4 T. The radial distance between3-D Hall sensorsis0.408 m, the most inner Hall sensorsare at0.092 moff the coil axis. 3-D Hall sensors V. Klyukhin, SINP MSU / CERN

  18. 3-D Hall sensors developedatNIKHEF (Netherlands) • selection by single Chip-Select signal • module identification by 64-bit ID-chip • readout/control by SPI (Serial Peripheral Interface) • used in ATLAS and CMS V. Klyukhin, SINP MSU / CERN

  19. The Hall sensors Calibration at GHMFL(Grenoble, France) The Hall sensorcalibration is done at4.5, 3.5, and2.5 Tfield on May 30 − June 3, 2005 inside the130 mm bore resistive magnet M5 in GHMFL at Grenoble with relative accuracy of5∙10−4. V. Klyukhin, SINP MSU / CERN

  20. Magnetic Flux Density Measured with Hall sensorsNear the CMS Coil Axis at B0=4.01 T Magnetic flux density measured withHall sensorsat radius0.092malong the coil axis in the range of±3.5 mwith respect to the coil transverse middle plane in full azimuth coverage atB0=4.01 T central filed. Averaging for each Z-coordinate over the full range of azimuth angle gives typical standard deviation of 4·10-5 T. The general precision of the measurements is7·10-4. V. Klyukhin, SINP MSU / CERN

  21. Measured and Calculated (2009) Magnetic Flux Density at the coil axis for B0=4.01 T V. Klyukhin, SINP MSU / CERN

  22. Measured and Calculated (2009) Magnetic Flux Density the coil axis for B0=4.01 T The measurements performed at R=0 m with NMR probe located on the coil axis in the middle of the fieldmapper (filled markers) differ from the calculated values (magenta curve) by 3.6±1.2mT (opened markers). V. Klyukhin, SINP MSU / CERN

  23. Measured and Calculated (2014) Magnetic Flux Density at the coil axis for B0=4.01 T V. Klyukhin, SINP MSU / CERN

  24. Measured and Calculated (2009) Magnetic Flux Density the coil axis for B0=4.01 T The measurements performed at R=0 m with NMR probe located on the coil axis in the middle of the fieldmapper (filled markers) differ from the calculated values (magenta curve) by 2.4±1.3mT (opened markers). V. Klyukhin, SINP MSU / CERN

  25. Measured and Calculated (2009) Magnetic Flux Density at R=0.092 m for B0=4.01 T V. Klyukhin, SINP MSU / CERN

  26. Measured and Calculated (2009) Magnetic Flux Density at R=0.092 m for B0=4.01 T The measurements performed at R=0.092 m with Hall sensor located on the negative fieldmapper arm (thick blue curve) differ from the calculated values (dashed red curve) by 2.1±2.0 mT (light blue square dots). The measurements performed at R=0.092 m with Hall sensor located on the positive fieldmapper arm (thin green curve) differ from the calculated values (dashed red curve) by 1.4±1.6 mT (light green round dots). V. Klyukhin, SINP MSU / CERN

  27. Measured and Calculated (2014) Magnetic Flux Density at R=0.092 m for B0=4.01 T V. Klyukhin, SINP MSU / CERN

  28. Measured and Calculated (2014) Magnetic Flux Density at R=0.092 m for B0=4.01 T The measurements performed at R=0.092 m with Hall sensor located on the negative fieldmapper arm (thick blue curve) differ from the calculated values (dashed red curve) by 0.4±2.3 mT (light blue square dots). The measurements performed at R=0.092 m with Hall sensor located on the positive fieldmapper arm (thin green curve) differ from the calculated values (dashed red curve) by ‒0.3±1.9 mT (light green round dots). V. Klyukhin, SINP MSU / CERN

  29. Measured and Calculated (2009) Magnetic Flux Density at R=1.724 m for B0=4.01 T V. Klyukhin, SINP MSU / CERN

  30. Measured and Calculated (2009) B at R=1.724 m for B0=4.01 T The measurements performed at R=1.724 m with NMR probe located on the negative fieldmapper arm (blue rhombs) differ from the calculated values (red curve) by 4.0±1.0 mT (goldtriangles). The measurements performed at R=1.724 m with Hall sensor located on the negative fieldmapper arm (blue open squares) differ from the calculated values (red curve) by 2.9±2.2 mT (goldslanted crosses). The measurements performed at R=1.724 m with Hall sensor located on the positive fieldmapper arm (blue open circles) differ from the calculated values (red curve) by 3.5±1.4 mT (gold right crosses). V. Klyukhin, SINP MSU / CERN

  31. Measured and Calculated (2014) Magnetic Flux Density at R=1.724 m for B0=4.01 T V. Klyukhin, SINP MSU / CERN

  32. Measured and Calculated (2014) B at R=1.724 m for B0=4.01 T The measurements performed at R=1.724 m with NMR probe located on the negative fieldmapper arm (blue rhombs) differ from the calculated values (red curve) by 1.4±0.7 mT (goldtriangles). The measurements performed at R=1.724 m with Hall sensor located on the negative fieldmapper arm (blue open squares) differ from the calculated values (red curve) by 1.4±0.7 mT (goldslanted crosses). The measurements performed at R=1.724 m with Hall sensor located on the positive fieldmapper arm (blue open circles) differ from the calculated values (red curve) by 1.4±0.7 mT (gold right crosses). V. Klyukhin, SINP MSU / CERN

  33. The CMS Current Cycles in August 2006 Test 19.14 kA 17.55 kA TheCMSmagnet operational current is 18.164 kA V. Klyukhin, SINP MSU / CERN

  34. Location of Flux Loopsand Immovable Hall sensors V. Klyukhin, SINP MSU / CERN

  35. Flux loops description • 22flux loops are performed from the flat ribbon cable of 45 wires that has been wound 7÷10 times around 12 blocks of W0, W-1, W-2, D-1, and D-2 at the bottom 30ºor 18º azimuth sectors • The areas enclosed by the flux loops vary from 0.31 to 1.59 m² on the barrel wheels and from 0.5to 1.13 m² on the end-cap disks • The voltages read out with seven DAQ modules USB-1208LS of Measurement Computing with 4 differential 12-bit analog inputs • The DAQ modules are attached by the USB cables to two network-enabled AnywhereUSB®/5 hubs connected to PC through 3Com® OfficeConnect® Dual Speed Switch 5 sitting on local Ethernet cable of 90 m. V. Klyukhin, SINP MSU / CERN

  36. Hall Sensors Used for Validation V. Klyukhin, SINP MSU / CERN

  37. Magnetic Flux Density at Y= ‒4.805, ‒5.66, and ‒6.685 m (17.55 kA) V. Klyukhin, SINP MSU / CERN

  38. Magnetic Flux Density at Y= ‒4.805, ‒5.66, and ‒6.685 m (19.14 kA) V. Klyukhin, SINP MSU / CERN

  39. Comparison of Calculation and Measurements • Total uncertainty of the flux loop measurements is 8.55% and includes the errors in the knowledge of the flux loops geometries and the errors of measured flux of (1.5±1.5)% • The calculated values differ from the measures B by (0.59±7.41)% in the barrel wheels and (‒4.05±1.97)% in the end-cap disks at the current of 17.55 kA • The calculated values differ from the measures B by (1.41±7.15)% in the barrel wheels and (‒2.87±2.00)% in the end-cap disks at the current of 19.14 kA • The error bars of the 3-D Hall sensor measurements are ± (0.025±0.015) mT at the current of 17.55 kA and ± (0.012±0.001) mT at the current of 19.14 kA in average • The model perfectly describes the magnetic flux density distribution inside the CMS coil within 0.1% in accordance with the previous model V. Klyukhin, SINP MSU / CERN

  40. Conclusions • The new CMS magnet model is developed to prepare the magnetic field maps for the upgraded CMS detector. The model is validated by the comparison of the calculated magnetic flux density with the measurements done in the CMS magnet selected regions with the flux loops and 3-D Hall sensors. V. Klyukhin, SINP MSU / CERN

  41. BACKUP V. Klyukhin, SINP MSU / CERN

  42. V. Klyukhin, SINP MSU / CERN

  43. Central Magnetic Flux Density Measured with the NMR-Probes vs. CMS Coil Current V. Klyukhin, SINP MSU / CERN

  44. The CMS Inner Volume Measured Field Map The field map is measured on a meshof 48 ΔØ = 7.5 degree (+1)steps x 140 ΔZ = 5 cm (+1)steps 4 xΔR = 408 mm (+1) steps within |Z|<3500 mm, R<1724 mm with 10Hall sensorsand 2NMR probes(at R=0 and R=1724 mm) at2,3,3.5,3.8, and4 Tcentral field. The distance in Z between the Hall sensors located on positive and negative fieldmapper arms is 0.95 m and in the range of Z from -2.55 to 2.55 m the measurements have been performed twice. V. Klyukhin, SINP MSU / CERN

  45. “Fast” Discharges of the CMS Coil 19.14 kA 17.55 kA 15.0 kA The CMS magnet working current in present time is 18.164 kA 12.5 kA V. Klyukhin, SINP MSU / CERN

  46. VoltagesInduced in the W-1 blocksandthe Integrated Magnetic Flux Densities Integrated Magnetic Flux Densities Voltages The voltages induced in the flux loops during “fast” (190 s time constant) discharges of the CMS coil have been integrated off-line with time for at least 1300 s. V. Klyukhin, SINP MSU / CERN

  47. Magnetic Flux Density at Y=‒5.66 m V. Klyukhin, SINP MSU / CERN

  48. Magnetic Flux Density at Z= ‒7.565 m V. Klyukhin, SINP MSU / CERN

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