1 / 11

COBRA Magnet Status

COBRA Magnet Status. W.Ootani MEG Experiment Review Meeting, Jul. 2004. COBRA Excitation at π E5. Apr.13 COBRA installation Apr.13-15 Cryostat evacuation Apr.16-19 Cooling Apr.21-26 Excitation Excitation test (Superconducting Magnet(SC) and Compensation Coils(NC))

beamon
Download Presentation

COBRA Magnet Status

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. COBRA Magnet Status • W.Ootani • MEG Experiment Review Meeting, Jul. 2004

  2. COBRA Excitation at πE5 • Apr.13 COBRA installation • Apr.13-15 Cryostat evacuation • Apr.16-19 Cooling • Apr.21-26 Excitation • Excitation test (Superconducting Magnet(SC) and Compensation Coils(NC)) • Fringing field measurements and test of active shielding in πM3 • PMT test for Timing counter inside COBRA • PMT test for LXe calorimeter near COBRA • Apr.29 Beam is back

  3. COBRA Installation in πE5 • COBRA placed at almost right place on beam line without platform.

  4. Excitation at πE5 • Only 4days for cooling thanks to LN2 pre-cooling. • Both SC and NC successfully tested at full operating current. (The first time to fully test NC.) • COBRA provided perfectly stabilized field (ΔB/B<0.05%) for PMT tests.

  5. Fringing Field Measurements Fringing field measured at πE5 [Gauss] 4.2 6.8 9.1 6.7 18.5 83.8 50.5 9.0 33.5 433.7 440.3 31.2 7.5 20.4 73.3 56.3 69.7 19.8 7.8 11.6 11.3

  6. Fringing Field Measurements Fringing field measured outside area [Gauss] 0.5 1.6 1.6 1.6 8.4 6.1 4.0 πE5 2.1 3.3 4.8

  7. Fringing Field Measurements Requirement Measured μE1< 20mG Neighboring area 0.5G πE3 μLan < 1G μCap < 1G 2-4G ECRIT< ?G 1-2G πE5 πM32 GPS < 20mG 1.8G πM33 LTF < 20mG 0.3G πM3 beam line Kicker < ?G Septum < ?G 3.3G 4.8G

  8. Fringing Field Measurements • Fringing field was measured as predicted (unfortunately). • The problems are being fixed for most places. • Fringing field was successfully compensated in μSR facilities at πM3 using compensating coils. Control system has to be implemented. • Fringing field at πE3 seems possible to be reduced < 1G by passive shielding. • Detector at ECRIT did not work when COBRA was ON. • Effect on kicker and septum in πM3 beam line has to be checked.

  9. Possible Solution in πE3 • Installation of active shielding in the detector (μLAN, μCAP) is difficult because of limited space and cost(?). • Passive shielding • Shielding box built with 5mm-thick soft iron plates (5m-D, 4m-W, 3m-H) • No front wall for minimizing influence on beam optics • Roof might not be necessary. (For good accessibility) Without roof With roof Beam Beam

  10. Summary • COBRA magnet was installed in πE5 and totally tested. • PMT tests were carried out by using COBRA field. • ΔB/B<0.05% • Stray field around LXe detector region is successfully canceled. • Fringing field was measured in the neighboring beam line and problems are being fixed. • It was found that active shielding is able to compensate COBRA field very well. • Calibration of field mapping machine will be made this year. • System alignment • Calibration of Hall sensors • Investigate possibility to use NMR • Field map reconstruction • Final field measurement is supposed to be carried out during shutdown period in 2006 after beam line commissioning is finished.

  11. Schedule Feb. 2004 Jul. 2004

More Related