1. Peter-Raymond Kettle MEG Review February 2007 1 BeamBeam LineLine StatusStatus

2. Peter-Raymond KettleMEG Review February 20072 Situation @ last Review Beam Study at Centre of COBRA with – Beam Study at Centre of COBRA with – 4cm Tg.E + Degrader System Needed !!! 4cm Tg.E + Degrader System Needed !!! full beam line @ centre COBRA tested only with 6cm Tg.E so far full beam line @ centre COBRA tested only with 6cm Tg.E so far full beam line @ centre COBRA 4cm Tg.E without Degrader full beam line @ centre COBRA 4cm Tg.E without Degrader Beam Study at Centre of COBRA with – Beam Study at Centre of COBRA with – 4cm Tg.E + Degrader System Needed !!! 4cm Tg.E + Degrader System Needed !!! full beam line @ centre COBRA tested only with 6cm Tg.E so far full beam line @ centre COBRA tested only with 6cm Tg.E so far full beam line @ centre COBRA 4cm Tg.E without Degrader full beam line @ centre COBRA 4cm Tg.E without Degrader TopTop Outstanding Problems to be solved: 1. Beam Misalignment due to Solenoidal Bfield Asymmetry caused by magnet material under hall floor by magnet material under hall floor 2. Muons prematurely ranging-out due to air/gas contamination + inadequate mixing in/of COBRA He-atmosphere inadequate mixing in/of COBRA He-atmosphere 3. APD-Array System needed for future phase space measurements Outstanding Problems to be solved: 1. Beam Misalignment due to Solenoidal Bfield Asymmetry caused by magnet material under hall floor by magnet material under hall floor 2. Muons prematurely ranging-out due to air/gas contamination + inadequate mixing in/of COBRA He-atmosphere inadequate mixing in/of COBRA He-atmosphere 3. APD-Array System needed for future phase space measurements Remaining Components: US End-CapUS End-Cap DS End-CapDS End-Cap Insertion SystemInsertion System + Drive System + Drive System Remaining Components: US End-CapUS End-Cap DS End-CapDS End-Cap Insertion SystemInsertion System + Drive System + Drive System

3. Peter-Raymond KettleMEG Review February 20073 Full MEG Beam Line 11 Main Components All now Implemented DSEnd-Cap + Insertion System DSEnd-Cap US End-Cap BTSBTS DegraderDegrader Triplet I + II + Seperator Steering Magnet CollimatorCollimator Compensation Coils 4x Compensation

4. Peter-Raymond KettleMEG Review February 20074 Problem Solving: 1) Beam Misalignment Compensation Coils 4x Compensation Horizontal (SM41H) + Vertical (SM41V) Steering Magnets made, placed on DS-side BTS – Between focii (water-cooled) Power Supplies installed on gallery Horizontal (SM41H) + Vertical (SM41V) Steering Magnets made, placed on DS-side BTS – Between focii (water-cooled) Power Supplies installed on gallery SMH41SMH41 SMV41SMV41 Power Supplies: 2x 250A(limited 200A) 55V unipolar Ramp-rate 0.5A/s (BTS/COBRA) Bdl = 24 G  m at 200A Power Supplies: 2x 250A(limited 200A) 55V unipolar Ramp-rate 0.5A/s (BTS/COBRA) Bdl = 24 G  m at 200A *** No simple solution for Compensation *** *** No simple solution for Compensation *** Since phase space rotation in BTS & COBRA Horizontal field:  Vertical & Horizontal displacement Vertical field:  Horizontal & Vertical displacement Hence for given correction at given z Hence for given correction at given z  Solve simultaneous equations  Solve simultaneous equations *** No simple solution for Compensation *** *** No simple solution for Compensation *** Since phase space rotation in BTS & COBRA Horizontal field:  Vertical & Horizontal displacement Vertical field:  Horizontal & Vertical displacement Hence for given correction at given z Hence for given correction at given z  Solve simultaneous equations  Solve simultaneous equations

5. Peter-Raymond KettleMEG Review February 20075 Problem Solving: 2) Gas Quality + Mixing Last Run: Air Contamination responsible for Muons Ranging-out gradient 3-9% air along z 7-11% (air + C 2 H 6 ) with DCs 7-11% (air + C 2 H 6 ) with DCs New Run: Improved COBRA He-System With End-Caps 3 Volumes treated separately 3 Volumes treated separately (i)Central Volume (i)Central Volume (ii+iii) US+DS End-Cap (ii+iii) US+DS End-Cap distributed equalized-flow distributed equalized-flow inlets inlets equalized flow outlets equalized flow outlets Pressure Regulation Pressure Regulation He-Monitoring He-Monitoring Last Run: Air Contamination responsible for Muons Ranging-out gradient 3-9% air along z 7-11% (air + C 2 H 6 ) with DCs 7-11% (air + C 2 H 6 ) with DCs New Run: Improved COBRA He-System With End-Caps 3 Volumes treated separately 3 Volumes treated separately (i)Central Volume (i)Central Volume (ii+iii) US+DS End-Cap (ii+iii) US+DS End-Cap distributed equalized-flow distributed equalized-flow inlets inlets equalized flow outlets equalized flow outlets Pressure Regulation Pressure Regulation He-Monitoring He-Monitoring

6. Peter-Raymond KettleMEG Review February 20076 Problem Solving: 3) APD-Array System Geiger-mode APD APD-Array 10 mm pitch APD-Array Fast Photoniques Preamp Preamp Fast Photoniques Preamp Preamp Geiger-mode APD Single mounted Test yy xx x- y-distributions Beam Test: Photonique Geiger-mode APD + BCF20 Scintillator (2x2)mm 2 + BCF20 Scintillator (2x2)mm 2 large gain/rate dependence large gain/rate dependence  modify R 1 R 2 on Preamp  modify R 1 R 2 on Preamp optimized preamp. Bias voltage vs. gain optimized preamp. Bias voltage vs. gain radiation damage studied radiation damage studied Beam Test: Photonique Geiger-mode APD + BCF20 Scintillator (2x2)mm 2 + BCF20 Scintillator (2x2)mm 2 large gain/rate dependence large gain/rate dependence  modify R 1 R 2 on Preamp  modify R 1 R 2 on Preamp optimized preamp. Bias voltage vs. gain optimized preamp. Bias voltage vs. gain radiation damage studied radiation damage studied 1748pixels1748pixels BackfaceBackface Discovered high radiation damage sensitivity to e + &  s -pixels don’t recover > dark current fluence > dark current fluence LIFE EXPECTANCY ~ 8 hrs in full beam  CANNOT USE for ARRAY !!!!  CANNOT USE for ARRAY !!!! Discovered high radiation damage sensitivity to e + &  s -pixels don’t recover > dark current fluence > dark current fluence LIFE EXPECTANCY ~ 8 hrs in full beam  CANNOT USE for ARRAY !!!!  CANNOT USE for ARRAY !!!! Intensive investigation started at PSI with Photoniques varies makes geiger-mode APD Investigated  ALL show similar effects!!!! Intensive investigation started at PSI with Photoniques varies makes geiger-mode APD Investigated  ALL show similar effects!!!!

7. Peter-Raymond KettleMEG Review February 20077 Component Status: US End-Cap COBRA US End-Cap Manufactured & assembled & INSTALLED COBRA US End-Cap Manufactured & assembled & INSTALLED US End-Cap Gas Distribution System INSTALLED US End-Cap Gas Distribution System INSTALLED COBRA US End-Cap Manufactured & assembled & INSTALLED COBRA US End-Cap Manufactured & assembled & INSTALLED US End-Cap Gas Distribution System INSTALLED US End-Cap Gas Distribution System INSTALLED VacuumChamberconnectionVacuumChamberconnection N 2 Bag + TC TC N 2 Bag + TC TC Outside View Inside View Installation with N 2 -Bag Not Optimal Not Optimal have learned how to have learned how to improve on several improve on several points !!! points !!! Installation Finished 12/10/2006 InsideCOBRA N 2 -Bag EC sand- wich foil Arrived 13/7/2006

8. Peter-Raymond KettleMEG Review February 20078 DS End-Cap & Insertion System Problem with frictional drive of Insertion System (IS) – Designed Kurath Eng. - Built Bieri Eng. Too weak for frictional Force We managed the impossible with Bieri Eng. !!! Design + Construction of New Drive System + adaptation to IS + delivery  *** 3 WEEKS ***  *** 3 WEEKS *** Problem with frictional drive of Insertion System (IS) – Designed Kurath Eng. - Built Bieri Eng. Too weak for frictional Force We managed the impossible with Bieri Eng. !!! Design + Construction of New Drive System + adaptation to IS + delivery  *** 3 WEEKS ***  *** 3 WEEKS *** Installed 14/12/2006 Delivered 24/10/2006 NBR Bellows System Stroke ~ 1.6m Stroke ~ 1.6m NBR Bellows System Stroke ~ 1.6m Stroke ~ 1.6m New Belt-driven Insertion System under test at Bieri Engineering Winterthur New Belt-driven Insertion System under test at Bieri Engineering Winterthur Belt driven system

9. Peter-Raymond KettleMEG Review February 20079 Target System polyesterpolyester Rohacell DC Support Pneumatic Drive Drive Movement Polyester/Rohacell target Pneumatic (He) drive Target System: 175  m Polyester ellipse 210x70 mm 175  m Polyester ellipse 210x70 mm Rohacell support frame + stems Rohacell support frame + stems strain-relieved target mount strain-relieved target mount He-driven pneumatic insertion He-driven pneumatic insertion electronic position end-markers electronic position end-markers *** System Worked Very Well *** *** System Worked Very Well *** Expected Muon Stop-rate: R s ~ 0.62R 0 R 0 = incoming muon rate Decay + He interaction ~12% R 0 Stop in slanted target ~ 70% R 0 Target System: 175  m Polyester ellipse 210x70 mm 175  m Polyester ellipse 210x70 mm Rohacell support frame + stems Rohacell support frame + stems strain-relieved target mount strain-relieved target mount He-driven pneumatic insertion He-driven pneumatic insertion electronic position end-markers electronic position end-markers *** System Worked Very Well *** *** System Worked Very Well *** Expected Muon Stop-rate: R s ~ 0.62R 0 R 0 = incoming muon rate Decay + He interaction ~12% R 0 Stop in slanted target ~ 70% R 0 DCsDCs Inside COBRA in parking position USTCsUSTCs

10. Peter-Raymond KettleMEG Review February 200710 Commissioning Run Dec. 2006 US COBRA Commissioning finished 28/11/2006 US COBRA Commissioning finished 28/11/2006 delays to closing DS End-Cap DC/N 2 -Bag conflict delays to closing DS End-Cap DC/N 2 -Bag conflict waiting for IS to be delivered waiting for IS to be delivered Full Beam Line (all components), 4cm Tg.E Ready 14/12/2006 *** 9 DAYS of Beam Left *** 14/12/2006 *** 9 DAYS of Beam Left *** Naturally decide to Maximize Commissioning time for DC, TC, Trigger, DAQ testing BUT priority beam Question to be answered first  Beam Misalignment Compensation at COBRA centre Lost time to finish studies Lost time to finish studies  2007  2007 US COBRA Commissioning finished 28/11/2006 US COBRA Commissioning finished 28/11/2006 delays to closing DS End-Cap DC/N 2 -Bag conflict delays to closing DS End-Cap DC/N 2 -Bag conflict waiting for IS to be delivered waiting for IS to be delivered Full Beam Line (all components), 4cm Tg.E Ready 14/12/2006 *** 9 DAYS of Beam Left *** 14/12/2006 *** 9 DAYS of Beam Left *** Naturally decide to Maximize Commissioning time for DC, TC, Trigger, DAQ testing BUT priority beam Question to be answered first  Beam Misalignment Compensation at COBRA centre Lost time to finish studies Lost time to finish studies  2007  2007 collimatorcollimatorcentredcentred above DegraderDegrader APD Problem solved APD Problem solved (temporarily) (temporarily) Large depletion layer Large depletion layer (non-Geiger mode) + v. fast Preamp sag-compensated 2-D sag-compensated 2-D Scanner with >3.5 m reach APD Problem solved APD Problem solved (temporarily) (temporarily) Large depletion layer Large depletion layer (non-Geiger mode) + v. fast Preamp sag-compensated 2-D sag-compensated 2-D Scanner with >3.5 m reach

11. Peter-Raymond KettleMEG Review February 200711 Commissioning Run Provisional Results Collimator Collimator transmission ε = 95% Collimator Collimator transmission ε = 95% Data still under Analysis PROVISIONAL Rate at Entrance COBRA 1.15  10 8  + s -1 at 1.8mA, 4cm Tg Rate at COBRA centre > 6  10 7  + s -1 at 1.8mA, 4cm Tg (under investigation) Beam Spot σ ~ 10.8 mm (as expected) Data still under Analysis PROVISIONAL Rate at Entrance COBRA 1.15  10 8  + s -1 at 1.8mA, 4cm Tg Rate at COBRA centre > 6  10 7  + s -1 at 1.8mA, 4cm Tg (under investigation) Beam Spot σ ~ 10.8 mm (as expected) Separation Quality Separation Quality High Intensity (slits open) 7.4σ Low Intensity 8.1σ Separation Quality Separation Quality High Intensity (slits open) 7.4σ Low Intensity 8.1σ e+e+e+e+ e+e+e+e+ ++++ ++++ Low Intensity SMH41 SMV41 SMH41 SMV41 Correction Correction at at Centre of COBRA ~ 2 mm Horizontally ~ 2 mm Horizontally ~ 7 mm Vertically ~ 7 mm Vertically CORRECTION CORRECTION WORKS !!! WORKS !!! COBRAcentreCOBRAcentre COBRAcentreCOBRAcentre