1. MEG Review Meeting June 2006 1 Peter-Raymond Kettle Beam Line Line Status StatusBeam Line Line Status Status

2. MEG Review Meeting June 2006 2 Peter-Raymond Kettle 1.Degrader Commissioning Run Commissioning Run Results Results 1.Degrader Commissioning Run Commissioning Run Results Results Topics to be Addressed 2. COBRA He-atmosphere He-atmosphere 3. COBRA/BTS Fringe Field Beam alignment influence influence 3. COBRA/BTS Fringe Field Beam alignment influence influence 5.  - Beam Test BTS 4. COBRA End-Cap & Insertion + Drive System Status 4. COBRA End-Cap & Insertion + Drive System Status 1. 2. 4.4.4.4. 5. 3. 6.. Target System

3. MEG Review Meeting June 2006 3 Peter-Raymond Kettle Degrader Run Status Total 5 weeks planned: Many Problems encountered & several Surprises Total 5 weeks planned: Many Problems encountered & several Surprises However: some interesting facts learned !!! However: some interesting facts learned !!! Goal: Goal: first time measurement of Beam in COBRA with Degrader first time measurement of Beam in COBRA with Degrader System deployed at the centre of BTS System deployed at the centre of BTS understand misalignment problem seen Dec. 2005 understand misalignment problem seen Dec. 2005Complications:  First time 6cm Target E employed during MEG Commissioning time  Lost more than 2 weeks of real beam time 11 days due to accelerator 11 days due to accelerator 2 days due to controller problems 3-D scanner 2 days due to controller problems 3-D scanner 1 day control computer problems BTS 1 day control computer problems BTS 1 day Separator vacuum interlock problems 1 day Separator vacuum interlock problems  Measurements stopped 4 last days lost due to interference COBRA stray field with other Users beam lines µSR  M3 (LTF, GPS)  E3 µCap-Expt. field with other Users beam lines µSR  M3 (LTF, GPS)  E3 µCap-Expt.  Run Programme SHORTENED Could Not Finish everything !!! Total 5 weeks planned: Many Problems encountered & several Surprises Total 5 weeks planned: Many Problems encountered & several Surprises However: some interesting facts learned !!! However: some interesting facts learned !!! Goal: Goal: first time measurement of Beam in COBRA with Degrader first time measurement of Beam in COBRA with Degrader System deployed at the centre of BTS System deployed at the centre of BTS understand misalignment problem seen Dec. 2005 understand misalignment problem seen Dec. 2005Complications:  First time 6cm Target E employed during MEG Commissioning time  Lost more than 2 weeks of real beam time 11 days due to accelerator 11 days due to accelerator 2 days due to controller problems 3-D scanner 2 days due to controller problems 3-D scanner 1 day control computer problems BTS 1 day control computer problems BTS 1 day Separator vacuum interlock problems 1 day Separator vacuum interlock problems  Measurements stopped 4 last days lost due to interference COBRA stray field with other Users beam lines µSR  M3 (LTF, GPS)  E3 µCap-Expt. field with other Users beam lines µSR  M3 (LTF, GPS)  E3 µCap-Expt.  Run Programme SHORTENED Could Not Finish everything !!!

4. MEG Review Meeting June 2006 4 Peter-Raymond Kettle 1 st Surprise: Missing Rate from 6 cm Target! P µ AHW AHU AHV R 4cm =(0.55±0.05)R 6cm (1.8) R 4cm =(0.55±0.05)R 6cm (1.8) Measured  L. Simons et al (Pions!!!) Measured  L. Simons et al (Pions!!!) from geometry alone would expect ~ 0.67 (1.5) R 4cm =(0.55±0.05)R 6cm (1.8) R 4cm =(0.55±0.05)R 6cm (1.8) Measured  L. Simons et al (Pions!!!) Measured  L. Simons et al (Pions!!!) from geometry alone would expect ~ 0.67 (1.5) Very PROVISIONAL !!! Measured R 6cm ~ 1.24 R 4cm With slits open However: - at 1.8mA 6cm Target ~ 1.1 ·10 9 e + /s at 4cm Target ~ 7.7 ·10 8 e + /s at factor 1.38 factor 1.38 ** Naïve Model could explain missing µ + rate **: Surface µ +  Target Surface e+  Target Volume Very PROVISIONAL !!! Measured R 6cm ~ 1.24 R 4cm With slits open However: - at 1.8mA 6cm Target ~ 1.1 ·10 9 e + /s at 4cm Target ~ 7.7 ·10 8 e + /s at factor 1.38 factor 1.38 ** Naïve Model could explain missing µ + rate **: Surface µ +  Target Surface e+  Target Volume Low energy  -production X-sections  rel. stop density factors back face/side face/front face = 3.3/2.5/1.7 Low energy  -production X-sections  rel. stop density factors back face/side face/front face = 3.3/2.5/1.7 ProjectedIntensity dist. dist. (surface) (surface) Target E 4/6 cm If interpretation Correct  6 cm Target BAD for MEG Don’t gain µ + have ~ 1.4 more background e + If interpretation Correct  6 cm Target BAD for MEG Don’t gain µ + have ~ 1.4 more background e + EXPECTED EXPECTED

5. MEG Review Meeting June 2006 5 Peter-Raymond Kettle 2 nd Surprise: Beam Misalignment Cause! Bfield measurements with triple-axis Tesla meter & BTS showed: Bfield measurements with triple-axis Tesla meter & BTS showed: BTS Bfield asymmetry at symmetric distances from axis of max. 10G (below axis) BTS Bfield asymmetry at symmetric distances from axis of max. 10G (below axis) Equivalent to extra Dipole field Equivalent to extra Dipole field symmetry points above/below axis for equal Bfield ~ 30 cm displaced (therefore symmetry points above/below axis for equal Bfield ~ 30 cm displaced (therefore not error in measurement) not error in measurement) Area Floor exhibits Remanence & Hysterisis (remembers if BTS +ve/-ve polarity) Area Floor exhibits Remanence & Hysterisis (remembers if BTS +ve/-ve polarity) fields very reproducible, max. value on Area Floor fields very reproducible, max. value on Area Floor  Shows iron under the floor !!! which causes field lines to be diverted & alters the symmetry of the solenoidal field at a point which is important for focusing symmetry of the solenoidal field at a point which is important for focusing Further field measurements after DC-test – with COBRA & BTS ON !!! Further field measurements after DC-test – with COBRA & BTS ON !!! Enquired about Hall floor- plans should exist lay-out for 40t/m 2 40 cm thick layer of steel reinforced concrete 40 cm thick layer of steel reinforced concrete steel layer ~ 30 cm thick starts about 10 cm down steel layer ~ 30 cm thick starts about 10 cm down high-quality steel but NOT STAINLESS !!! high-quality steel but NOT STAINLESS !!! Enquired about Hall floor- plans should exist lay-out for 40t/m 2 40 cm thick layer of steel reinforced concrete 40 cm thick layer of steel reinforced concrete steel layer ~ 30 cm thick starts about 10 cm down steel layer ~ 30 cm thick starts about 10 cm down high-quality steel but NOT STAINLESS !!! high-quality steel but NOT STAINLESS !!!

6. MEG Review Meeting June 2006 6 Peter-Raymond Kettle 3 rd Surprise: Muons Prematurely Range-out! 100% 50% R~ 1460 mm He T MAT Expected: 100% transmission to centre COBRA, 100% transmission to centre COBRA, 50% to ~ end COBRA 50% to ~ end COBRA After degrader ~21 MeV/c entry to COBRA Measured: Mean Range at COBRA z= -900 mm R ~1460 mm He Equiv. R ~1460 mm He Equiv.  235 µm CH 2  235 µm CH 2 Extra Material Thickness T MAT ~ 900 mm He Equiv. or 145 µm CH 2 OR  9 % Air Contamination OR  9 % Air Contamination Know that air back diffusion Know that air back diffusion via leaks problematic as well as via leaks problematic as well as suspect “laminar flow” Mixing! suspect “laminar flow” Mixing! test measurement after DC-Test test measurement after DC-Test Measure Range Curve Measure Range Curve post BTS to test Momentum post BTS to test Momentum hypothesis hypothesis 18MeV/c  18 MeV/c in He in He

7. MEG Review Meeting June 2006 7 Peter-Raymond Kettle Beam Test Conclusions more than 2 weeks of real beam time lost mainly due to the accelerator more than 2 weeks of real beam time lost mainly due to the accelerator 6 cm target proved problematic since beam wasn’t as expected & 6 cm target proved problematic since beam wasn’t as expected & took time to investigate took time to investigate possible explanation for lack of increase in µ + rate from 6 cm Target possible explanation for lack of increase in µ + rate from 6 cm Target if true 6 cm Target No good for MEG signal/noise(e + ) bad if true 6 cm Target No good for MEG signal/noise(e + ) bad magnetic field anomaly found (Iron in floor) causes BTS field asymmetry & beam magnetic field anomaly found (Iron in floor) causes BTS field asymmetry & beam misalignment (further investigation needed) misalignment (further investigation needed) good He circulation crucial for MEG – possible cause of our muons ranging-out good He circulation crucial for MEG – possible cause of our muons ranging-out range curve post degrader & BTS should answer this range curve post degrader & BTS should answer this Need extra Beam Time (4 weeks) with 4 cm Target + Degrader Only possible after end July (4cm Target) –start 4cm Target unstable + low Only possible after end July (4cm Target) –start 4cm Target unstable + low Current MEGAPIE Current MEGAPIE Only possible after COBRA stray field influence on other beams solved Only possible after COBRA stray field influence on other beams solved To Not Delay MEG - has to be when End-Caps mounted – however problem To Not Delay MEG - has to be when End-Caps mounted – however problem no magnet measuring machine possible therefore NEW APD array Detector no magnet measuring machine possible therefore NEW APD array Detector NEEDED – (presented Tokyo Meeting) NEEDED – (presented Tokyo Meeting) Need extra Beam Time (4 weeks) with 4 cm Target + Degrader Only possible after end July (4cm Target) –start 4cm Target unstable + low Only possible after end July (4cm Target) –start 4cm Target unstable + low Current MEGAPIE Current MEGAPIE Only possible after COBRA stray field influence on other beams solved Only possible after COBRA stray field influence on other beams solved To Not Delay MEG - has to be when End-Caps mounted – however problem To Not Delay MEG - has to be when End-Caps mounted – however problem no magnet measuring machine possible therefore NEW APD array Detector no magnet measuring machine possible therefore NEW APD array Detector NEEDED – (presented Tokyo Meeting) NEEDED – (presented Tokyo Meeting)

8. MEG Review Meeting June 2006 8 Peter-Raymond Kettle Question of Muons Muons “Ranging-out” “Ranging-out” Question of Muons Muons “Ranging-out” “Ranging-out”

9. MEG Review Meeting June 2006 9 Peter-Raymond Kettle COBRA He-Atmosphere Measure Profiles @ Centre COBRA  X = 11.8 mm  Y = 12.0 X 0 4mm offset Y 0 on axis Rate ~ 8 ·10 7 µ + /s at 1.8mA, 6cm Target ~ 64% of muons ~ 64% of muons reach centre !!! reach centre !!! Measure Profiles @ Centre COBRA  X = 11.8 mm  Y = 12.0 X 0 4mm offset Y 0 on axis Rate ~ 8 ·10 7 µ + /s at 1.8mA, 6cm Target ~ 64% of muons ~ 64% of muons reach centre !!! reach centre !!! WHY?WHY? 1. Too much material in beam? Degrader too thick?Degrader too thick? New beam window >190 micronsNew beam window >190 microns Mylar Mylar Air contamination in He !!!Air contamination in He !!! 2.Momentum too low? 6cm Target (transverse offset) ???6cm Target (transverse offset) ??? AHW41 Bending magnetAHW41 Bending magnet measured momentum spectrum measured momentum spectrum 1. Too much material in beam? Degrader too thick?Degrader too thick? New beam window >190 micronsNew beam window >190 microns Mylar Mylar Air contamination in He !!!Air contamination in He !!! 2.Momentum too low? 6cm Target (transverse offset) ???6cm Target (transverse offset) ??? AHW41 Bending magnetAHW41 Bending magnet measured momentum spectrum measured momentum spectrum CheckedChecked CheckedChecked Muons Range-out prematurely

10. MEG Review Meeting June 2006 10 Peter-Raymond Kettle Beam Materials & Momentum Degrader: – 33 measurements per foil made Degrader: – 33 measurements per foil made New Mylar Window: - 16 measurements of New Mylar Window: - 16 measurements of sample of same foil made sample of same foil made Beam Momentum: - Integral & Differential Range Curve Beam Momentum: - Integral & Differential Range Curve measured post BTS using 50µm & 100 µm measured post BTS using 50µm & 100 µm Mylar foils Mylar foils Mylar foils + Holder Mylar foils + Holder APD+ Holder

11. MEG Review Meeting June 2006 11 Peter-Raymond Kettle Momentum Measurement Lowthreshold Highthreshold + 45.5 mm Air + 20 µm Al foil Counts µ+e Counts µ+e no threshold dependence no threshold dependence Michel MS ~ same for all Michel MS ~ same for all measurements measurements Counts µ+e Counts µ+e no threshold dependence no threshold dependence Michel MS ~ same for all Michel MS ~ same for all measurements measurements Counts µ only (Landau!) Counts µ only (Landau!) possible threshold dependence possible threshold dependence Counts µ only (Landau!) Counts µ only (Landau!) possible threshold dependence possible threshold dependence  T µ  = (2230 ± 60)keV  P µ  = (21.8 ± 0.3)MeV/c 3.8% higher than expected, Possible with 6cm Tg ! Gives lateral shift – p change  T µ  = (2230 ± 60)keV  P µ  = (21.8 ± 0.3)MeV/c 3.8% higher than expected, Possible with 6cm Tg ! Gives lateral shift – p change Mylar  R LL  = 355 µm  R UL  = 389 µm Mylar  R LL  = 355 µm  R UL  = 389 µm BEAM MOMENTUM OK !!!

12. MEG Review Meeting June 2006 12 Peter-Raymond Kettle COBRA He-atmosphere TU-1530 He-Monitor (Japan) Range 0-100% He Range 0-100% He accuracy ±1 % accuracy ±1 % Probe part magnetic Probe part magnetic TU-1530 He-Monitor (Japan) Range 0-100% He Range 0-100% He accuracy ±1 % accuracy ±1 % Probe part magnetic Probe part magnetic 2 Measurements used as cross-check Sonic Gas Monitor SGM (home-made) Calibrated Range 92-100% He Calibrated Range 92-100% He precision ±0.3 % precision ±0.3 % microphone + speaker magnetic microphone + speaker magnetic Sonic Gas Monitor SGM (home-made) Calibrated Range 92-100% He Calibrated Range 92-100% He precision ±0.3 % precision ±0.3 % microphone + speaker magnetic microphone + speaker magnetic

13. MEG Review Meeting June 2006 13 Peter-Raymond Kettle He Monitor Cross Calibration HeHe AirAir Gas Rack (mixer) True He-mixture TU-153  3.5% SGM  0.2% Measured Conc n TU-153 Monitor needs correction within 92-100% Range of  3.5% within 92-100% Range of  3.5% TU-153 Monitor needs correction within 92-100% Range of  3.5% within 92-100% Range of  3.5%

14. MEG Review Meeting June 2006 14 Peter-Raymond Kettle COBRA He-Measurements TU-153 sample He via inserted tube Sampling points: A: SGM B: z = + 2085 mm C: z = + 705 mm D: z = + 45 mm E: z = - 355 mm SGM TU-153 AA BB CC DDEE Pos Comm Run DC Run B 97% 93% C 96% 92% D 90% 89% E 91% 89% Pos Comm Run DC Run B 97% 93% C 96% 92% D 90% 89% E 91% 89% He-gradient, worst US !!! He-gradient, worst US !!! explains ranging-out of Muons explains ranging-out of Muons He gas distribution too simple He gas distribution too simple Care with final gas system !!! Care with final gas system !!! He-gradient, worst US !!! He-gradient, worst US !!! explains ranging-out of Muons explains ranging-out of Muons He gas distribution too simple He gas distribution too simple Care with final gas system !!! Care with final gas system !!! P r o v i s i o n a l 7% to 11% Air 3% to 9% Air

15. MEG Review Meeting June 2006 15 Peter-Raymond Kettle Beam Misalignment & BTS + COBRA Influence BTS + COBRA Influence Beam Misalignment & BTS + COBRA Influence BTS + COBRA Influence

16. MEG Review Meeting June 2006 16 Peter-Raymond Kettle Beam Misalignment/Fringe Field Problem Initial field measurements during this run with BTS ONLY showed:  iron under the floor !!! which causes field lines to be diverted & alters the symmetry of the solenoidal field at a point which is important for focusing symmetry of the solenoidal field at a point which is important for focusing Measurements extended to Final BTS settings + COBRA Series of measurements done at US & DS faces of BTS with US & DS faces of BTS with BTS alone & BTS +COBRA: Asymmetry (beam pipe dia.) BTS alone: US ~ 6 G, C ~ 7G, DS ~ 5G BTS + COBRA: US ~ 6G, C ~ 0.6G, DS ~ 29G Series of measurements done at US & DS faces of BTS with US & DS faces of BTS with BTS alone & BTS +COBRA: Asymmetry (beam pipe dia.) BTS alone: US ~ 6 G, C ~ 7G, DS ~ 5G BTS + COBRA: US ~ 6G, C ~ 0.6G, DS ~ 29G

17. MEG Review Meeting June 2006 17 Peter-Raymond Kettle Radial BTS Symmetry (No COBRA) US DS Top Berg Aare Bot Top Berg Aare Bot BTS Measured radial Symmetry distributions US/DS at ~ beam pipe Diameter I= -200A v. Simple “c-of-g” v. Simple “c-of-g” interpretation interpretation Magnetic axis centre Magnetic axis centre US: r=2.1 mm,  =292.5° Field Asymmetry ~ 11G Field Asymmetry ~ 11G DS: r= 6.0 mm,  =247.5° Field Asymmetry ~ 33 G Field Asymmetry ~ 33 G BTS Measured radial Symmetry distributions US/DS at ~ beam pipe Diameter I= -200A v. Simple “c-of-g” v. Simple “c-of-g” interpretation interpretation Magnetic axis centre Magnetic axis centre US: r=2.1 mm,  =292.5° Field Asymmetry ~ 11G Field Asymmetry ~ 11G DS: r= 6.0 mm,  =247.5° Field Asymmetry ~ 33 G Field Asymmetry ~ 33 G

18. MEG Review Meeting June 2006 18 Peter-Raymond Kettle Radial COBRA Asymmetry BTS+COBRA TopTop Bot t COBRA Measured radial symmetry distribution US at ~ beam pipe diameter I BTS = -203A, I COBRA =360/320A I BTS = -203A, I COBRA =360/320A v. Simple “c-of-g” interpretation v. Simple “c-of-g” interpretation Magnetic axis centre Magnetic axis centre US: r=1.7 mm,  =240° US: r=1.7 mm,  =240° asymmetry ~ 55G asymmetry ~ 55G Problem to be studied by PSI Magnet Group !!! COBRA Measured radial symmetry distribution US at ~ beam pipe diameter I BTS = -203A, I COBRA =360/320A I BTS = -203A, I COBRA =360/320A v. Simple “c-of-g” interpretation v. Simple “c-of-g” interpretation Magnetic axis centre Magnetic axis centre US: r=1.7 mm,  =240° US: r=1.7 mm,  =240° asymmetry ~ 55G asymmetry ~ 55G Problem to be studied by PSI Magnet Group !!! COBRAcentre COBRAcentre Influence on µ-Beam COBRA Beam Centroid Excursion COBRA Beam Centroid Excursion

19. MEG Review Meeting June 2006 19 Peter-Raymond Kettle COBRA End-Cap + Insertion & Drive System Insertion & Drive System COBRA End-Cap + Insertion & Drive System Insertion & Drive System

20. MEG Review Meeting June 2006 20 Peter-Raymond Kettle COBRA US End-Cap System USUSDSDS US End-Cap schedule Bieri Engineering manufacture costs ~ 55 kCHf Bieri Engineering manufacture costs ~ 55 kCHf delivery to PSI – THIS WEEK (2 weeks late) delivery to PSI – THIS WEEK (2 weeks late)

21. MEG Review Meeting June 2006 21 Peter-Raymond Kettle Insertion System Connects to accelerator Beam pipe Gliding support rings NBR RETRACTED into End-Cap Replacewithwindow Gas-tight to He-side CH 2 /EVAL window Gas-tight to He-side CH 2 /EVAL window normally connected to motor-driven accelerator normally connected to motor-driven accelerator beam tube beam tube frictional hand-drive via electric drill/crank-handle frictional hand-drive via electric drill/crank-handle Detailed FEM study Electric-drill or hand drive View from Inside COBRA

22. MEG Review Meeting June 2006 22 Peter-Raymond Kettle COBRA DS End-Cap + Insertion & Drive Systems Complication encountered with DS End-Cap + Insertion & Drive System: Offer received from Bieri Engineering ~ 200kCHf !!! successful negotiations with PSI Management for extra money MEG project raised to priority 1 again – hence PSI workshops can take-over assembly & testing of complete system … Bieri price now ~ 140 kCHf Delivery schedule: End-August DS End-Cap (as planned but v. tight) Delivery schedule: End-August DS End-Cap (as planned but v. tight) Mid-September Insertion & Drive System Mid-September Insertion & Drive System

23. MEG Review Meeting June 2006 23 Peter-Raymond Kettle BTS  -Beam Test  -Beam TestBTS

24. MEG Review Meeting June 2006 24 Peter-Raymond Kettle BTS Pion Beam Test 1 st MEG  -beam Studies in 2004: part of momentum spectrum study part of momentum spectrum study 25-33 MeV/c 25-33 MeV/c dedicated runs at 56 MeV/c & 103 MeV/c dedicated runs at 56 MeV/c & 103 MeV/c CEX run in  E5 at 112 MeV/c Oct. 2004 CEX run in  E5 at 112 MeV/c Oct. 2004 ALL BEFORE BTS ARRIVED!!! ALL BEFORE BTS ARRIVED!!! Problem: BTS cannot be excited to transmit Momenta >> 70 MeV/c since maximum I BTS ~ 270 A maximum I BTS ~ 270 A exceeds allowed force on COBRA coils exceeds allowed force on COBRA coils Results Results  - Integral Spot Rates in MHz  - Integral Spot Rates in MHz for 1,8mA Proton Current & 4cm Target E Measured UPSTREAM of BTS position Normalized to Momentum Slit Settings: Normalized to Momentum Slit Settings: FS41L/R 250/280 FS43L/R 240/220 FS41L/R 250/280 FS43L/R 240/220 Results Results  - Integral Spot Rates in MHz  - Integral Spot Rates in MHz for 1,8mA Proton Current & 4cm Target E Measured UPSTREAM of BTS position Normalized to Momentum Slit Settings: Normalized to Momentum Slit Settings: FS41L/R 250/280 FS43L/R 240/220 FS41L/R 250/280 FS43L/R 240/220 56 MeV/c R  = 7.6 ·10 6  - /s slits open R  = 7.2 ·10 5  - /s slits70/70 R  = 7.2 ·10 5  - /s slits70/70 56 MeV/c R  = 7.6 ·10 6  - /s slits open R  = 7.2 ·10 5  - /s slits70/70 R  = 7.2 ·10 5  - /s slits70/70 Solution: - should be able to transmit 56 Mev/c particles (2*28 MeV/c) with Good optics Solution: - should be able to transmit 56 Mev/c particles (2*28 MeV/c) with Good optics Single Node SNM SNM Double Node DNM DNM 56 MeV/c 28 MeV/c Measured US BTS

25. MEG Review Meeting June 2006 25 Peter-Raymond Kettle BTS  -Beam Test cont. BTS test done last week: Problem encountered – Hamamatsu APD used for µ + (no scint. but utilize “Nuclear Counter Effect”) used for µ + (no scint. but utilize “Nuclear Counter Effect”) has no pulse-ht. resolution for  - CANNOT DISTINGUISH e - &  - has no pulse-ht. resolution for  - CANNOT DISTINGUISH e - &  - measured at 56 MeV/C & 107 MeV/c with APD & Pill Counter (scintillator) measured at 56 MeV/C & 107 MeV/c with APD & Pill Counter (scintillator) see pions & electrons with pill-counter BUT CANNOT USE WITH BTS BFIELD see pions & electrons with pill-counter BUT CANNOT USE WITH BTS BFIELDHOWEVER: COULD TRANSMIT 56 MeV/c PARTICLES as expected BTS Excitation Curve For 56 MeV/c particles Question: What are expected low-energy What are expected low-energy Pion Beam Rates at centre of COBRA? Pion Beam Rates at centre of COBRA?Question: What are expected low-energy What are expected low-energy Pion Beam Rates at centre of COBRA? Pion Beam Rates at centre of COBRA?

26. MEG Review Meeting June 2006 26 Peter-Raymond Kettle BTS  -Beam Test cont. CONCLUSION: APDs with scintillators needed for Expt. APDs with scintillators needed for Expt. Cross-System of 13 APDs must be built Cross-System of 13 APDs must be built before final Commissioning with 4cm Tg before final Commissioning with 4cm Tg max.  - momentum for good optics max.  - momentum for good optics ~ 70 MeV/c !!! ~ 70 MeV/c !!! expected rate (slits open) 1.6 MHz at COBRA centre expected rate (slits open) 1.6 MHz at COBRA centreCONCLUSION: APDs with scintillators needed for Expt. APDs with scintillators needed for Expt. Cross-System of 13 APDs must be built Cross-System of 13 APDs must be built before final Commissioning with 4cm Tg before final Commissioning with 4cm Tg max.  - momentum for good optics max.  - momentum for good optics ~ 70 MeV/c !!! ~ 70 MeV/c !!! expected rate (slits open) 1.6 MHz at COBRA centre expected rate (slits open) 1.6 MHz at COBRA centre Expected low-energy Pion Beam Rates at centre COBRA for 1.8 mA Proton Beam 4 cm Tg. Taking decay-rate into account Expected low-energy Pion Beam Rates at centre COBRA for 1.8 mA Proton Beam 4 cm Tg. Taking decay-rate into account Expected Pion Beam Rates Centre COBRA 70 MeV/c  ~ 1.6MHz at 1.8mA I PROT 70 MeV/c  ~ 1.6MHz at 1.8mA I PROT

27. MEG Review Meeting June 2006 27 Peter-Raymond Kettle Target System UCI UCI Target System UCI UCI

28. MEG Review Meeting June 2006 28 Peter-Raymond Kettle Target System Mechanical Requirements Substantial Progress made with Target System since last Review !!! Supported from DC Support Structure Supported from DC Support Structure externally surveyed & introduced with DCs externally surveyed & introduced with DCs possibility to move target for End-Cap Insertion System introduction (C-W, LH 2,…) possibility to move target for End-Cap Insertion System introduction (C-W, LH 2,…)  “ target parking”  “ target parking” Mechanically stable & reproducible positioning Mechanically stable & reproducible positioning DC Support Structure InsertionBellows DC structure “Target Parking” New method of “Parking” using Translation rather than Rotation Target movement

29. MEG Review Meeting June 2006 29 Peter-Raymond Kettle Target System Characteristics Present Target Characteristics: Ellipse (210 x 70)mm Polyester foil 175 µm Ellipse (210 x 70)mm Polyester foil 175 µm freely suspended by support pins from a freely suspended by support pins from a thin Rohacell support frame at ~22° to axis thin Rohacell support frame at ~22° to axis (differential expansion) (differential expansion) frame attached by Rohacell support stems frame attached by Rohacell support stems mounted on v. thin movable rods mounted on v. thin movable rods Driven by pneumatic drive Driven by pneumatic drive Present Target Characteristics: Ellipse (210 x 70)mm Polyester foil 175 µm Ellipse (210 x 70)mm Polyester foil 175 µm freely suspended by support pins from a freely suspended by support pins from a thin Rohacell support frame at ~22° to axis thin Rohacell support frame at ~22° to axis (differential expansion) (differential expansion) frame attached by Rohacell support stems frame attached by Rohacell support stems mounted on v. thin movable rods mounted on v. thin movable rods Driven by pneumatic drive Driven by pneumatic drive polyesterpolyester Rohacell DC Support Pneumatic Drive Drive Movement Current Status UCI: prototype system prototype system successfully tested successfully tested Final System All parts machined All parts machined Assembly & testing about Assembly & testing about to start to start target foil material & angle target foil material & angle still under study still under study

30. MEG Review Meeting June 2006 30 Peter-Raymond Kettle Prototype Target & Performance Test Setup UCI Pins on which film is hung Screws for clamping frame Rohacell Frame DC Support Tube Tube Thin film (~175 micron) target – material to be determined Thin film (~175 micron) target – material to be determined “soft” polyethylene too difficult to maintain flat “soft” polyethylene too difficult to maintain flat Various polyester, polystyrene, “hard” polyethylene materials possible Various polyester, polystyrene, “hard” polyethylene materials possible Implementation Implementation Target flatness controlled by Rohacell frame – clamping two frames together allows control of flatness Target flatness controlled by Rohacell frame – clamping two frames together allows control of flatness Hanging film between frames Hanging film between frames allows for differential expansion allows for differential expansion without deformation of film without deformation of film Distance between frames controlled Distance between frames controlled by washers at screw locations by washers at screw locations Final frame cut precisely with high Final frame cut precisely with high speed CNC router speed CNC router Nylon screws/nuts used to reduce mass Nylon screws/nuts used to reduce mass

31. MEG Review Meeting June 2006 31 Peter-Raymond Kettle Prototype Target & Performance cont. Flatness measured by reflected laser off target surface and measuring reflected angle as laser spot is scanned across target. Z(x,y) = Z(0,0) + ∫ (dz/dx)dx + ∫(dz/dy)dy Flatness measured by reflected laser off target surface and measuring reflected angle as laser spot is scanned across target. Z(x,y) = Z(0,0) + ∫ (dz/dx)dx + ∫(dz/dy)dy Target measured to be flat to less than +/-100 microns Target measured to be flat to less than +/-100 microns Target Size Study Measured 45° target  88% stops Slanted target gives “leakage” due to MS Relatively insensitive to vertical size down to 5.7cm Relatively insensitive to length down to 19 cm HOWEVER Thickness of 175 microns required Final Parameters + slope sense still under study

32. MEG Review Meeting June 2006 32 Peter-Raymond Kettle Schedule US End-Cap: US End-Cap: Delivery US COBRA End-Cap: end June Delivery US COBRA End-Cap: end June US End-Cap preparations mounting PSI workshops 6WD installation after US TC US End-Cap preparations mounting PSI workshops 6WD installation after US TC US End-Cap installation 5WD Beg. Sept. US End-Cap installation 5WD Beg. Sept. Target System: Production End July Production End July Target assembly + installation 2W Target assembly + installation 2W DS End-Cap + Insertion & Drive System: Delivery DS COBRA End-Cap End Aug. – Mid Sept. Delivery DS COBRA End-Cap End Aug. – Mid Sept. Delivery Insertion + Drive System Mid Sept. Delivery Insertion + Drive System Mid Sept. DS End-Cap preparations mounting PSI workshops 6WD installation after DS TC DS End-Cap preparations mounting PSI workshops 6WD installation after DS TC Insertion & Drive System mounting + testing PSI workshops 6WD Insertion & Drive System mounting + testing PSI workshops 6WD DS End-Cap + Insertion & Drive System installation 10WD End. Sept. DS End-Cap + Insertion & Drive System installation 10WD End. Sept. Beam Commissioning (degrader + 4cm Tg.) Beam Line setup + survey 5WD post US End-Cap Beg. Sept. Beam Line setup + survey 5WD post US End-Cap Beg. Sept. BTS cryo-connections + pump & cool-down 8WD BTS cryo-connections + pump & cool-down 8WD Beam Commissioning Run 4Weeks Beg. Oct. Beam Commissioning Run 4Weeks Beg. Oct. Pion Beam Tune CEX 7D (if not during Comm. Run) before LXe Calib. Mid. Dec. Pion Beam Tune CEX 7D (if not during Comm. Run) before LXe Calib. Mid. Dec.