1. May 9, 2002 TRIUMF Canada1 A new   e  experiment at PSI For the MUEGAMMA collaboration Stefan Ritt (Paul Scherrer Institute, Switzerland) Motivation Experimental Technique New Electronics Current status

2. May 9, 2002 TRIUMF Canada2 Physics Motivation Minimal SM: Conservation of Baryons (proton decay) and Lepton Flavour (  +  e +  Super Symmetry (SUSY) theories generically predict LFV Processes like  +  e +  are not “contaminated” by SM processes and therefore very clean Discovered oscillations are expected to enhance LFV rate The search for  +  e +  is therefore a promising field to find physics beyond the SM Minimal SM: Conservation of Baryons (proton decay) and Lepton Flavour (  +  e +  Super Symmetry (SUSY) theories generically predict LFV Processes like  +  e +  are not “contaminated” by SM processes and therefore very clean Discovered oscillations are expected to enhance LFV rate The search for  +  e +  is therefore a promising field to find physics beyond the SM

3. May 9, 2002 TRIUMF Canada3 Prediction from SUSY SU(5) This experiment 2) 1) 1)J. Hisano et al., hep-ph/9711348 2)MEGA collaboration, hep-ex/9905013 Based on observation of atmospheric neutrino anomaly BR(  +  e +  )  10 -14 BR(  ±   ±  )  10 -9 Conversion(   e)  10 -16 Based on observation of atmospheric neutrino anomaly BR(  +  e +  )  10 -14 BR(  ±   ±  )  10 -9 Conversion(   e)  10 -16

4. May 9, 2002 TRIUMF Canada4 Connection with oscillations 1) J. Hisano and D. Nomura, Phys. Rev. D59 (1999) 116005 This experiment favored!

5. May 9, 2002 TRIUMF Canada5 Previous  +  e +  Experiments PlaceYear Upper limit Author SIN (PSI), Switzerland 1977< 1.0  10 -9 A. Van der Schaaf et al. TRIUMF, Canada1977< 3.6  10 -9 P. Depommier et al. LANL, USA1979 < 1.7  10 -10 W.W. Kinnison et al. LANL, USA1986< 4.9  10 -11 R.D. Bolton et al. LANL, USA1999< 1.2  10 -11 MEGA Collab., M.L. Brooks et al. PSI~2005~ 10 -14 This Experiment Search for Lepton-Flavour Violation: Search for Lepton-Flavour Violation:

6. May 9, 2002 TRIUMF Canada6 MEG Collaboration InstituteCountryMain Resp.HeadScientistsStudents ICEPP, Univ. of TokyoJapanLXe CalorimeterT. Mori122 Waseda UniversityJapanCryogenicsT. Doke52 INFN, PisaItaly e + counter, trigger, M.C. C. Bemporad43 IPNS, KEK, TsukubaJapan Supercoducting Solenoid A. Maki5- PSISwitzerland Drift Chamber, Beamline, DAQ S. Ritt4- BINP, NovosibirskRussia LXe Tests and Purification B. Khazin4- Nagoya UniversityJapanCryogenicsK. Masuda1- 35 7

7. May 9, 2002 TRIUMF Canada7 Time Table 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 PlanningR & DAssemblyData Taking now “large prototype”

8. May 9, 2002 TRIUMF Canada8 Experimental Method

9. May 9, 2002 TRIUMF Canada9 Detector Overview Stopped  beam of 10 8 s -1, 100% duty factor Liquid Xe calorimeter for  detection Solenoidal magnetic spectrometer with gradient field Radial drift chambers for e + momentum determination Timing counter for e + Stopped  beam of 10 8 s -1, 100% duty factor Liquid Xe calorimeter for  detection Solenoidal magnetic spectrometer with gradient field Radial drift chambers for e + momentum determination Timing counter for e + E e = 52.8 MeV Kinematics  e  = 180° E g = 52.8 MeV e  

10. May 9, 2002 TRIUMF Canada10 Signal and Background  +  e +  signal very clear –E  = E e+ = 52.8 MeV –   e+ = 180° –e + and  in time Background –Radiative  + decays –Accidental overlap Detector Requirements –Excellent energy resolution –Excellent timing resolution –Good angular resolution ee e  e   ee  e    e  e 

11. May 9, 2002 TRIUMF Canada11   e  Signature  e  E e,E  = 52.8MeV  e  E e,E  < 52.8MeV X = E e /52.8MeV Y = E  /52.8MeV

12. May 9, 2002 TRIUMF Canada12 Sensitivity and Background Rate NN 1  10 8 T2.2  10 7 s (~50 weeks)  /4  0.09 ee 0.95  0.7  sel 0.8 FWHM EeEe 0.7% EE 1.4%  e  12 mrad tete 150 ps BR(  e  ) = (N  T  /4   e    sel ) -1 = 0.94  10 -14 Prompt Background B pr  10 -17 Accidental BackgroundB acc   E e  t e  (  E  ) 2 (  e  ) 2  5  10 -15 Aimed resolutions:

13. May 9, 2002 TRIUMF Canada13 Comparison with previous experiments Exp./Lab  E e /E e %FWHM  E  /E  %FWHM  t e  (ns)  e  (mrad) Inst. Stop rate (s -1 ) Duty cycle (%) SIN (PSI) 8.79.31.4-(4..6) x 10 5 100 TRIUMF108.76.7-2 x 10 5 100 LANL8.881.9372.4 x 10 5 6.4 Crystal Box 881.3874 x 10 5 (6..9) MEGA1.24.51.6172.5 x 10 8 (6..7) PSI0.71.40.151210 8 100

14. May 9, 2002 TRIUMF Canada14 Paul Scherrer Institute Experimental Hall

15. May 9, 2002 TRIUMF Canada15 Experimental Hall

16. May 9, 2002 TRIUMF Canada16  E5 Beam Line 10 8  /s on 5  5 mm 2 Neutron background measured in 1998 Two Beam tests in 2002 10 8  /s on 5  5 mm 2 Neutron background measured in 1998 Two Beam tests in 2002

17. May 9, 2002 TRIUMF Canada17 Detector

18. May 9, 2002 TRIUMF Canada18 LXe Calorimeter ~800l liquid Xe (3t) ~800 PMTs immersed in LXe Only scintillation light detected Fast response (45 ns decay time) High light output (70% of NaI(Tl)) 1) High uniformity compared with segmented calorimeters High channel occupancy will be accommodated by special trigger scheme ~800l liquid Xe (3t) ~800 PMTs immersed in LXe Only scintillation light detected Fast response (45 ns decay time) High light output (70% of NaI(Tl)) 1) High uniformity compared with segmented calorimeters High channel occupancy will be accommodated by special trigger scheme 1) T. Doke and K. Masuda, NIM A 420 (1999) 62

19. May 9, 2002 TRIUMF Canada19  Response Signal is distributed over many PMTs in most cases Weighted mean of PMTs on the front face   x ~ 4mm FWHM Broadness of distribution   z ~ 16mm FWHM Timing resolution   t ~ 100ps FWHM Energy resolution ~ 1.4% FWHM depends on light attenuation in LXe Signal is distributed over many PMTs in most cases Weighted mean of PMTs on the front face   x ~ 4mm FWHM Broadness of distribution   z ~ 16mm FWHM Timing resolution   t ~ 100ps FWHM Energy resolution ~ 1.4% FWHM depends on light attenuation in LXe x z

20. May 9, 2002 TRIUMF Canada20 Calorimeter Prototypes 32 PMTs, 2.3 l LXe Tested with radioactive sources 51 Cr, 137 Cs, 54 Mn, 88 Y Extrapolated resolutions at 52.8 MeV in agreement with quoted numbers “Small”“Large” Measure resolutions with 40 MeV photon beam at ETL, Tsukuba, Japan

21. May 9, 2002 TRIUMF Canada21 Large Prototype Currently largest LXe detector in the world (224 PMTs, 150l), Contains all critical parts of final detector

22. May 9, 2002 TRIUMF Canada22 Status of Large Prototype Two beam tests, many  -source and cosmic runs in Tsukuba, Japan Light attenuation much too high (~10x) Cause: ~3ppm of Water in Lxe Cleaning with “hot” Xe-gas before filling currently under investigation Preliminary results in June ‘02 Two beam tests, many  -source and cosmic runs in Tsukuba, Japan Light attenuation much too high (~10x) Cause: ~3ppm of Water in Lxe Cleaning with “hot” Xe-gas before filling currently under investigation Preliminary results in June ‘02

23. May 9, 2002 TRIUMF Canada23 Positron Spectrometer Homogeneous Field e + from  +  e +  Gradient Field (COnstant-Bending-RAdius) Ultra-Thin (~3g/cm2) superconducting solenoid with 1.2 T field Ultra-Thin (~3g/cm2) superconducting solenoid with 1.2 T field

24. May 9, 2002 TRIUMF Canada24 Drift Chamber 16 radial chambers with 20 wires each Staggered cells measure both position and time He – C 2 H 6 gas to reduce multiple scattering Vernier pattern to determine z coordinate 16 radial chambers with 20 wires each Staggered cells measure both position and time He – C 2 H 6 gas to reduce multiple scattering Vernier pattern to determine z coordinate

25. May 9, 2002 TRIUMF Canada25 Prototype Test at PSI 0, 0.6, 0.8, 1T field 3 tilting angles Chamber ok, electronics needs improvement 0, 0.6, 0.8, 1T field 3 tilting angles Chamber ok, electronics needs improvement

26. May 9, 2002 TRIUMF Canada26 Positron timing counter Aimed resolution ~100ps FWHM Tests with cosmic  confirmed 100ps FWHM Aimed resolution ~100ps FWHM Tests with cosmic  confirmed 100ps FWHM http://meg.psi.ch/ subprojects/tcount/ http://meg.psi.ch/ subprojects/tcount/

27. May 9, 2002 TRIUMF Canada27 Trigger Electronics

28. May 9, 2002 TRIUMF Canada28 Trigger Requirements  Beam rate10 8 s -1  Fast LXe energy sum > 45MeV2  10 3 s -1   interaction point  e + hit point in timing counter  time correlation  – e + 200 s -1  angular corrlation  – e + 20 s -1  Beam rate10 8 s -1  Fast LXe energy sum > 45MeV2  10 3 s -1   interaction point  e + hit point in timing counter  time correlation  – e + 200 s -1  angular corrlation  – e + 20 s -1 E e = 52.8 MeV Kinematics  e  = 180° E g = 52.8 MeV e   M.C. Total ~800 PMTs Common noise contributes significantly to analog sum AC coupling  Baseline drift How to evaluate  of shower center? Total ~800 PMTs Common noise contributes significantly to analog sum AC coupling  Baseline drift How to evaluate  of shower center?

29. May 9, 2002 TRIUMF Canada29 Digital Trigger Type1 8 channels clck, clear VME Interface (Cypress) 3.3V 2.5V FADC LVDS FPGA SRAM FADC LVDS FPGA SRAM LVDS 48 bits output 100MHz 10bit VME Interface (Cypress) 3.3V 2.5V FADC LVDS FPGA SRAM FADC LVDS FPGA SRAM LVDS 48 bits output 100MHz 10bit VME Interface (Cypress) 3.3V 2.5V FADC LVDS FPGA SRAM FADC LVDS FPGA SRAM LVDS 48 bits output 100MHz 10bit VME Interface (Cypress) 3.3V 2.5V FADC LVDS FPGA SRAM FADC LVDS FPGA SRAM LVDS 48 bits output 100MHz 10bit All PMTs in trigger Board hierarchy with LVDS interconnect Use FPGA with double capacity All PMTs in trigger Board hierarchy with LVDS interconnect Use FPGA with double capacity VME Interface (Cypress) 3.3V 2.5V LVDS FPGA SRAM LVDS FPGA SRAM LVDS Type2 LVDS

30. May 9, 2002 TRIUMF Canada30 Baseline Subtraction Latch Baseline Subtraction Latch 10 bit 100 MHz Clock    - + <thr  + - Baseline Register Uses ~120 out of 5000 logic cells  8 channels/FPGA use 20% of chip Uses ~120 out of 5000 logic cells  8 channels/FPGA use 20% of chip Baseline subtracted signal LUT 10x10 Calibrated and linearized signal

31. May 9, 2002 TRIUMF Canada31 QT Algorithm original waveform smoothed and differentiated (Difference Of Samples) Threshold in DOS Region for pedestal evaluation integration area t Inspired by H1 Fast Track Trigger (A. Schöning) Hit region defined when Difference of Samples is above threshold Integration of original signal in hit region Pedestal evaluated in region before hit Time interpolated using maximum value and two neighbor values in LUT  1ns resolution for 10ns sampling time Inspired by H1 Fast Track Trigger (A. Schöning) Hit region defined when Difference of Samples is above threshold Integration of original signal in hit region Pedestal evaluated in region before hit Time interpolated using maximum value and two neighbor values in LUT  1ns resolution for 10ns sampling time 10ns

32. May 9, 2002 TRIUMF Canada32 Trigger latency BS    Max...... T[ns] 0 50 100 110 120..200 220 230 >45MeV   e+ AND 10 stages = 1024 chn... ADC...... Inter-board communication: 120ns Total: 350ns (simulated) ~600 chn. / 10 bit At 100 MHz  75 GB/s processing power In 2 VME crates ~600 chn. / 10 bit At 100 MHz  75 GB/s processing power In 2 VME crates

33. May 9, 2002 TRIUMF Canada33 Prototype board ADC Signal- Generator DAC FPGA

34. May 9, 2002 TRIUMF Canada34 DAQ Electronics

35. May 9, 2002 TRIUMF Canada35 DAQ Requirements n E[MeV] 50 51 52 ee t PMT sum e    e    e  51.5 MeV 0.511 MeV  ’s hitting different parts of LXe can be separated if > 2 PMTs apart (15 cm) Timely separated  ’s need waveform digitizing > 300 MHz If waveform digitizing gives timing <100ps, no TDCs are needed  ’s hitting different parts of LXe can be separated if > 2 PMTs apart (15 cm) Timely separated  ’s need waveform digitizing > 300 MHz If waveform digitizing gives timing <100ps, no TDCs are needed ~100ns  e 

36. May 9, 2002 TRIUMF Canada36  Domino Sampling Chip C. Brönnimann et al., NIM A420 (1999) 264 Existing: 0.5 – 1.2 GHz sampling speed 128 sampling cells Readout at 5 MHz, 12 bit ~ 60 $/channel Needed: 2.5 GHz sampling speed Circular domino wave 1024 sampling cells 40 MHz readout < 100ps accuracy Existing: 0.5 – 1.2 GHz sampling speed 128 sampling cells Readout at 5 MHz, 12 bit ~ 60 $/channel Needed: 2.5 GHz sampling speed Circular domino wave 1024 sampling cells 40 MHz readout < 100ps accuracy

37. May 9, 2002 TRIUMF Canada37 Domino Ring Sampler (DRS) input Free running domino wave, stopped with trigger Sampling speed 2 GHz (500ps/bin), trigger gate sampling gives 50ps timing resolution 1024 bins  150ns waveform + 350ns delay Free running domino wave, stopped with trigger Sampling speed 2 GHz (500ps/bin), trigger gate sampling gives 50ps timing resolution 1024 bins  150ns waveform + 350ns delay

38. May 9, 2002 TRIUMF Canada38 DRS Prototype 4mm 1mm.......... 0.25  m Process (“CERN is using”) 768 cells Wafer back July ‘02

39. May 9, 2002 TRIUMF Canada39 Domino Simulation “Analog Extracted” 16 cells All paracitics included Domino speed: 1.5-2.2 GHz 16 cells All paracitics included Domino speed: 1.5-2.2 GHz

40. May 9, 2002 TRIUMF Canada40 DAQ Board 9 channels  1024 bins / 40 MHz = 230  s  acceptable dead time Zero suppression in FPGA QT Algorithm in FPGA (store waveform if multi-hit) Costs per channel: ~25$ (board) + 6$ (chip) 9 channels  1024 bins / 40 MHz = 230  s  acceptable dead time Zero suppression in FPGA QT Algorithm in FPGA (store waveform if multi-hit) Costs per channel: ~25$ (board) + 6$ (chip) VME Interface (Cypress) 3.3V 2.5V 8 channel DRS Trigger Input Board inter-connect FPGA SRAM FADC 8 channel DRS 8 channel DRS FADC 8 channel DRS Trigger BUS (2 nd level tr.) 8 inputs trigger gate FADC 3 state switches FPGA SRAM shift register 40 MHz 12 bit domino wave

41. May 9, 2002 TRIUMF Canada41 DAQ Topology PMT FADC FPGA trigger gate 2GHz 40MHz DC Trigger Board trigger gate 100MHz DSC Trigger Board CPU LXe e + counter wires strips Waveform or QT readout DAQ board Waveform or QT readout 2 nd level trigger 2 nd level trigger

42. May 9, 2002 TRIUMF Canada42 “Redefinition” of DAQ ConventionalNew AC couplingBaseline subtraction Const. Fract. Discriminator DOS – Zero crossing ADCNumerical Integration TDC Bin interpolation (LUT) Waveform Fitting Scaler (250 MHz)Scaler (50 MHz) OscilloscopeWaveform sampling 400 US$ / channel50 US$ / channel TDC Disc. ADC Scaler Scope FADC FPGA SRAM DRS ~GHz 100 MHz

43. May 9, 2002 TRIUMF Canada43 Cryogenics Design

44. May 9, 2002 TRIUMF Canada44 Slow Control HV PC RS232 12345 Temperature, pressure, … GPIB Valves ??? 15° C heater PLC 12:30 12.3 12:45 17.2 13:20 15.2 14:10 17.3 15:20 16.2 18:30 21.3 19:20 18.2 19:45 19.2 MIDAS DAQ Ethernet Terminal Server

45. May 9, 2002 TRIUMF Canada45 Slow Control Bus HV Temperature, pressure, …Valves heater MIDAS DAQ

46. May 9, 2002 TRIUMF Canada46 Field Bus Solutions CAN, Profibus, LON available Node with ADC >100$ Interoperatibility not guaranteed Protocol overhead Local CPU? User programmable? How to integrate in HV? (CAEN use CAENET) CAN, Profibus, LON available Node with ADC >100$ Interoperatibility not guaranteed Protocol overhead Local CPU? User programmable? How to integrate in HV? (CAEN use CAENET)

47. May 9, 2002 TRIUMF Canada47 Generic node ADuC812 / C8051Fxxx Micro controllers with 8x12 bit ADC, 2x12 bit DAC, digital IO RS485 bus over flat ribbon cable Powered through bus Costs ~30$ Piggy back board ADuC812 / C8051Fxxx Micro controllers with 8x12 bit ADC, 2x12 bit DAC, digital IO RS485 bus over flat ribbon cable Powered through bus Costs ~30$ Piggy back board www.cygnal.com

48. May 9, 2002 TRIUMF Canada48 2 Versions Generic node with signal conditioning Sub-master with power supply and PC connection (Parallel Port, USB planned) Integration on sensors, in crates RS232 node with protocol translator BUS Oriented Crate Oriented 19” crate with custom backplane Generic node as piggy-back Cards for analog IO / digital IO / °C / 220V crate connects to parallel port (USB)

49. May 9, 2002 TRIUMF Canada49 Midas Slow Control Bus 256 nodes, 65536 nodes with one level of repeaters Bus length ~500m opto-isolated Boards for voltage, current, thermo couples, TTL IO, 220V output Readout speed: 0.3s for 1000 channels C library, command-line utility, Midas driver, LabView driver Nodes are “self-documenting” Configuration parameters in EEPROM on node Node CPU can operate autonomously for interlock and regulation (PID) tasks (C programmable) Nodes can be reprogrammed over network http://midas.psi.ch/mscb 256 nodes, 65536 nodes with one level of repeaters Bus length ~500m opto-isolated Boards for voltage, current, thermo couples, TTL IO, 220V output Readout speed: 0.3s for 1000 channels C library, command-line utility, Midas driver, LabView driver Nodes are “self-documenting” Configuration parameters in EEPROM on node Node CPU can operate autonomously for interlock and regulation (PID) tasks (C programmable) Nodes can be reprogrammed over network http://midas.psi.ch/mscb

50. May 9, 2002 TRIUMF Canada50 V in V out 12 times DAC 2400V 0-2400V ADC Cheap and stable (<0.3V) HV system Regulate global external voltage Use series of opto-couplers Compensate non-linearities of opto- couplers by regulation loop ADC and DAC from slow control node Cheap and stable (<0.3V) HV system Regulate global external voltage Use series of opto-couplers Compensate non-linearities of opto- couplers by regulation loop ADC and DAC from slow control node HV System Design

51. May 9, 2002 TRIUMF Canada51 High Voltage System  C node Opto-couplers External HV

52. May 9, 2002 TRIUMF Canada52 HV performance Regulates common HV source 0-2400V, ~1mA DAC 16bit, ADC 14bit Current trip ~10  s Self-calibration with two high accuracy reference voltages Accuracy <0.3V absolute Boards with 12 channels, crates with 192 channels 30$/channel (+ext. HV) Regulates common HV source 0-2400V, ~1mA DAC 16bit, ADC 14bit Current trip ~10  s Self-calibration with two high accuracy reference voltages Accuracy <0.3V absolute Boards with 12 channels, crates with 192 channels 30$/channel (+ext. HV) Prototype

53. May 9, 2002 TRIUMF Canada53 Conclusions Decision about feasibility of LXe calorimeter soon Innovative electronics useful for other experiments –FPGA-based trigger with 100MHz FADC –2 GHz cheap waveform sampling –New slow control system MSCB Physics runs expected in 2005 Decision about feasibility of LXe calorimeter soon Innovative electronics useful for other experiments –FPGA-based trigger with 100MHz FADC –2 GHz cheap waveform sampling –New slow control system MSCB Physics runs expected in 2005 http://meg.psi.ch