1. Limited Streamer Tubes for the IFR Barrel Experimental Program Advisory Committee SLAC, June 12 2003 Stewart Smith INFN: Ferrara, Frascati, Genova, Padova, Roma US: Ohio State, Oregon Princeton, SLAC, UCSD

2. June 12, 2003EPAC Meeting2 Oct 2000: IFR flagged as major problem by Technical Review (Gilch)  Major R&D toward remediation – close but no cigar  Decision to upgrade endcap with RPC’s, launch R&D for barrel upgrade. Dec 2002: IFR Barrel Replacement Review Committee (Ratcliff, Hearty chairs) analyzed role of muon and K L ID in the current B A B AR physics program and in the program we foresee for the future. Committee’s report examines:  Solid angle coverage of IFR systems  Overview of relevant physics processes  Closer look at selected processes  Characteristics of the current IFR barrel  Simulation of new absorber configurations Recommendation of LST as new detector Motivation

3. June 12, 2003EPAC Meeting3 New layer New RPC belt 10cm steel 5 layers of 2.5 cm brass Upgrade of IFR Forward Endcap  5 brass layers  New RPC’s to improve efficiency  Installed summer 2002 Barrel  6 Brass layers  RPC  LST  2 sectors in 2004  4 more in 2005  cm = 0.52  cm = 0.23  cm = 0.25

4. June 12, 2003EPAC Meeting4 Physics Program for the IFR Muons are critical for many analyses over the long-term BaBar physics program:  Semileptonic decays  Leptonic decays  Electroweak penguins  Processes involving J/  or  (2S), including rare decays  Lepton tagging (CP, CPT studies, mixing, certain rare decays)  Reconstruction of B  D*l on one side of the event  R at low energies via Initial State Radiation Unthinkable for a comprehensive B-Factory detector not to have good muon identification.  Taken for granted in such experiments!  We need all the statistics we can get (rare decays, backgnd reduction, restricted areas of phase space, etc.).   / e comparisons to reduce systematic errors in precision measurements.

5. June 12, 2003EPAC Meeting5 Measurements using the IFR (I) Rating system: IFR gives *(some benefit), **( significant benefit), ***( large benefit), ****(essential information) Modes highlighted in red will be discussed in more detail.

6. June 12, 2003EPAC Meeting6 Measurements using the IFR (II) Most of these measurements are underway. Many will continue long into the future. (The comment ‘stat’ indicates that the measurement is statistics limited) R via initial state radiation g-2, etc ****

7. June 12, 2003EPAC Meeting7 Flavor-Changing Neutral Current Decays Possible new physics contributions B  Kℓ + ℓ -, B  K*ℓ + ℓ -, and B  X s ℓ + ℓ - Three diagrams in the Standard Model: penguins (  and the W + W - box:

8. June 12, 2003EPAC Meeting8 ICHEP 2002: 82 fb -1 B  K is rarest observed B decay ( ~8 x 10 -7 ) B  K ℓ + ℓ - is rarest observed B decay ( ~8 x 10 -7 ) Two leptons  very sensitive to e and  performance. Two leptons  very sensitive to e and  performance. Current sensitivity dominated by e + e - channels in B A B AR due to low  effic. (but not in Belle). Current sensitivity dominated by e + e - channels in B A B AR due to low  effic. (but not in Belle). Current significance: 4.4  (K); 2.8  (K*) Current significance: 4.4  (K); 2.8  (K*) B  Kℓ + ℓ -, B  K*ℓ + ℓ -, B  X s ℓ + ℓ -

9. June 12, 2003EPAC Meeting9 Muon Efficiency vs Time K(*)ee modes: e stable K(*)  modes:  lower and falling with time. Will lose 2/3 of the     events without IFR barrel.Will lose 2/3 of the     events without IFR barrel.

10. June 12, 2003EPAC Meeting10 Challenges: 1. Small branching fractions for b  uℓ 2. Large b  cℓ backgrounds. 3. Theoretical uncertainties from strong interaction effects. Experimental approaches with high potential to reduce theoretical errors  Exclusive B   ℓ at high q 2, using “neutrino reconstruction à la CLEO;” theory from lattice QCD.  Inclusive B  X u ℓ, using fully reconstructed B sample as tags; theory from heavy quark expansion. Both methods need large event samples.  /e comparison important as precision increases.  /e comparison important as precision increases. |V ub | from Rare Semileptonic Decay

11. June 12, 2003EPAC Meeting11 B  X u l B  X u l  (B  X u l  (  B  X c l  Can use more of lepton momentum range than in inclusive endpoint method. This reduces model dependence.  Inclusive B  X u l with Fully Reconstructed tags

12. June 12, 2003EPAC Meeting12 The IFR as Muon Detector 19 active layers, very finely segmented. 19 active layers, very finely segmented. There are only 5.1 int. There are only 5.1 int. RPCs in Layer 19 are dying, are inaccessible, and cannot be replaced. We will lose 10 cm of Fe, leaving only 4.5 int RPCs in Layer 19 are dying, are inaccessible, and cannot be replaced. We will lose 10 cm of Fe, leaving only 4.5 int This is marginal for a muon system. This is marginal for a muon system. p>1 GeV/c Spectrum of ranges in barrel for muons from B  X u l  (in int )

13. June 12, 2003EPAC Meeting13 Proposed Absorber Improvement Want to add as much absorber as possible, but we are highly constrained by earthquake considerations. Proposed configuration places more emphasis on muon ID, while still preserving most of the K L efficiency.  replace 6 active layers (5, 7, 9, 11, 13, 15) with 2.2 cm brass plates, compensating for the loss of layer 19 and bringing the total absorber thickness to about 5.3 int. This will be adequate for essentially all measurements.

14. June 12, 2003EPAC Meeting14 IFR Barrel Performance: Pion fake rate vs  (  ) Simple muon selector -- uses only int info. (neural net algorithms improve rejection by factor ~2) Design June 2002 LSTs Only LSTs + Brass Muon Efficiency (Monte Carlo) p  > 2 Gev/C

15. June 12, 2003EPAC Meeting15 The LST Team M. Andreotti, D. Bettoni, R. Calabrese†, V. Carassiti, G. Cibinetto, A. Cotta Ramusino, E. Luppi, M. Negrini, L. Piemontese Ferrara University and INFN R. Baldini, A. Calcaterra, U. Denni, P. Patteri, A Zallo Laboratori Nazionali di Frascati dell’INFN R. Capra, M. Lo Vetere, S. Minatoli, S. Passaggio, C. Patrignani, E. Robutti Genova University and INFN T. Allmendinger, K.K. Gan, K.Honscheid, H. Kagan, R. Kass, J.Morris, C. Rush, S.Smith, Q. Wong, M.Zoeller Ohio State University R. Frey, N. Sinev, D. Strom, J. Strube University of Oregon C. Fanin, M. Morandin, M. Posocco, M. Rotondo, R. Stroili, C. Voci Padova University and INFN J. Biesiada, G. Cavoto*, N. Danielson, R. Fernholz, Y. Lau, C. Lu, J. Olsen, W. Sands, A.J.S. Smith† Princeton University S. Morganti, G Piredda, C. Voena Roma “La Sapienza”University and INFN D.B. MacFarlane, H.P. Paar University of California at San Diego R. Boyce, P. Kim, J. Krebs, R. Messner, M. Olson, Z. Szalata, T. Webber, W. Wisniewski, C. Young Stanford Linear Accelerator Center Engineers † Contact persons * Also INFN Rome

16. June 12, 2003EPAC Meeting16 LST design Option 1: single-layer large cell (15x17 mm) Option 2: double-layer small cell (9x8mm) Readout of x and y coordinates in both options from outside strips Graphite- Coated PVC

17. June 12, 2003EPAC Meeting17 Large cell is the Baseline Mechanically more robust, Looser tolerances Lower failure rate  ~0.1%/year failure rate in Macro over more than a decade.  Comparable net efficiency loss to that of double/layer ~ 1.5 mm thinner Only ~1/3 as many cells  Simpler HV, Gas systems Significantly cheaper But, R&D slower off the mark than for small cells.  Required new dies, molds, to make full prototypes. Awaiting confirmation of performance to make final decision  Simulations, which agree with measurements on 9x9’s (E fields, resolutions, tolerances) are very encouraging.  Just today, prototypes at Frascati and Pol.Hi.Tech have been put under voltage – so far so good, but…. Should know within a week! Breaking News!

18. June 12, 2003EPAC Meeting18 Progress Since Decision 22 standard (9x9) tubes produced by vendor (Pol.Hi.Tech):  Early verification of vendor’s capability.  Good plateaux at factory with binary (flammable) gas mixture (larger than 500V)  Shipped to Ferrara, Princeton and Columbus, tests with ternary (safe) gas mixture underway. Preproduction prototypes underway (Ferrara, Frascati, Padova)  10 single layer (17x15) prototypes ordered: first tubes ready by Jun. 5  20 double layer (9x8) tubes ordered: first tube ready by Jun. 12 (delay due to dies production) Final strip prototypes:  and Z arrived in Ferrara.  Test of the readout chain underway (Ferrara)  Final strip setup  Final preamp-discriminator prototypes of Front End Card ready Electronics (Ferrara, Genova, Ohio State)  Detailed electrical schematics for Front End Card underway  Review at July workshop.

19. June 12, 2003EPAC Meeting19 Progress (cont’d) Integration/Installation work underway at SLAC  SLAC and Princeton engineers meet weekly.  Detailed work for the 2 sextants to be installed in 2004 (1 and 4) Workshops  Jan 11-12 in Princeton Conceptual design, organization, division of responsibilities  Mar 17/18 in Rome (and Pol.Hi.Tech). Mainly QC and final design for prototypes pre-production  Apr 24/26 in Columbus (US groups). Mainly assembly and installation issues  May 26/27 in Ferrara. Mainly QC, production issues, module assembly, preparation of documentation for EPAC Engineering Design Week: Jul. 14 – 18 at SLAC.  Final design, installation issues, and electronics review  Integrate SLAC and Outhouse engineering effort

20. June 12, 2003EPAC Meeting20 R&D activities Measurements of plateaux, pulse-heights, etc Aging tests Strip signal studies conductive rib effect on the phi strips; Q distribution on z strips Signal propagation, reflections at strip/cable connection E-field, drift-time characterization of large cell Gas flow studies: FEA simulation; Full length test results. Anode wire study: Surface quality; Effect of wire diameter on plateau width.

21. June 12, 2003EPAC Meeting21 9x9 Plateaux at PHT, binary gas Larger than 500 V (31% Ar; 69% Isobutane)

22. June 12, 2003EPAC Meeting22 Preliminary 9x9 plateaux, ternary (SLD) gas mixture (Ferrara) ~ 400 V wide plateau Gas mixture: CO 2 /C 4 H 10 /Ar(88/9.5/2.5) V threshold = 35mV  dead = 400ns

23. June 12, 2003EPAC Meeting23 Efficiency with cosmic ray trigger (OSU) Efficiency limited to < 100% By geometry ~400 volt plateau Ternary [ZEUS] Gas, 8% Isobutane

24. June 12, 2003EPAC Meeting24 Charge spectrum (in ternary gas) (Princeton) (ZEUS Gas -- 8% Isobutane) 30 mv 4700 V5000 V 5 mv 30 mv Trigger Threshold High Voltage

25. June 12, 2003EPAC Meeting25 Threshold effect on counting rate (Princeton) Charge spectrum suggests lack of clear transition between avalanche mode and streamer mode. Therefore the threshold will play a big role for the plateau. With 5mV instead of 30mV threshold, the plateau is much better even for ternary gas. Binary gas mix Zeus gas mix (8% Isobutane) (69% Isobutane)

26. June 12, 2003EPAC Meeting26 First Test of Large Cell (Frascati) Machined prototype, ~70cm long Cosmic Ray Singles Rate counted for 5 minutes SLD Gas (9.5% C 4 H 10 )  Maiden Voyage After ~1 hour # Counts High Voltage 200 V

27. June 12, 2003EPAC Meeting27 Aging Tests (Princeton)  Accumulated charge = 0.75C/cm (worst dose expected by 2010 = 0.1C/cm)  No big drop of the signal charge and self-sustaining discharge occurred.  The chamber is still running smoothly.

28. June 12, 2003EPAC Meeting28 Quality Control Absolutely crucial to get this right! Q/C procedures at Pol.Hi.Tech. (PHT)  Have been discussed, defined in various meetings with the company and have been accepted.  Test equipment to be supplied partly by INFN, and accepted by the company.  Tube acceptance criteria to be defined together with PHT.  Procedures and equipment in place by end of August Q/C and long term test procedures at US sites basically designed.

29. June 12, 2003EPAC Meeting29 Module Assembly Plan Ohio State and Princeton preparing facilities for module assembly. Both universities fabricating parts for assembly fixtures. Shipping and testing boxes are being designed. Planning for testing and quality control is in progress. Installation procedures coordinated by SLAC and Princeton engineers.

30. June 12, 2003EPAC Meeting30 Composition of Module Arrays (large cell) (Widths in mm) Circles indicate number of modules per sextant  strips

31. June 12, 2003EPAC Meeting31 Installation and Replacement of Modules Installation: corner and center plates removed. Replacement: center plate(s) removed, corner plates remain

32. June 12, 2003EPAC Meeting32 HV Power Supply (OSU, Padova) OSU HV System design in final phase  Further refined prototype. Ripple now < 25 mV, and will be significantly less with tube and HV capacitor connected. (CAEN specs list ripple as < 50 mV.)  First tests of control logic, current and voltage read-out  Full prototype  96 channels, 2u, 19’’ (twice the CAEN density) Current monitor for each channel, 48 ch. share common HV setting (12 in CAEN system) Diode protection circuit integrated. CAEN HV Supplies from LVD experiment may be available  OSU engineers believe the (ZEUS) diode protection circuit can be fit into the modules. Need to find solution for external HV distribution (SHV?)  Should be able to evaluate suitability and availability soon.

33. June 12, 2003EPAC Meeting33

34. June 12, 2003EPAC Meeting34 Ferrara

35. June 12, 2003EPAC Meeting35

36. June 12, 2003EPAC Meeting36 SIMULATION Goals  Implement a full GEANT4 based simulation No workaround Just try to understand the whole machinery and adapt to our need  Reuse as much code as we can  Work in the most recent functional release (12.5.2) Need to learn some new CDB technology  Understand the Detector Model mostly done Status  Working LST simulation Ready by the end of June  We continue to need help from the IFR experts  Already have had a lot of useful interactions...

37. June 12, 2003EPAC Meeting37 From Prototypes to Project June 12 -- EPAC Review June 15 -- Cost/Schedule/WBS prepared June 22 -- INFN Gruppo Uno Evaluation June 27 -- BaBar IFC Meeting June 30 -- Large/Small Cell Decision Aug 1 -- Place Orders for Tubes Oct 1 -- Tube Production begins Feb 1 ’04 -- 1/3 tubes shipped to Princeton/OSU May 1 -- Modules for 2 sextants to SLAC July 1 -- Installation of 2 sextants July 2005 -- Remaining 4 sextants (ready earlier)

38. June 12, 2003EPAC Meeting38 Summary 1. Physics with  ’s is essential to BABAR’s long-term program. 2. Barrel IFR provides about 50% of our muon acceptance.  In addition to the added statistical power, muons are also valuable because they have very different systematics from electrons (Different detectors, much less radiation than from electrons, etc.)  Important modes with 2 leptons, such as B  Kll, B  K*ll, and B  X s ll, would be severely affected without the barrel replacement. 3. Muon ID suffers from inadequate material in current IFR.  Already marginal, exacerbated by impending demise of layer 19.  Muon ID can be significantly improved by replacing some of the active detector layers with brass. 4. LST project is well underway, strong INFN/US team in place. With strong competition from Belle and soon from CDF, BABAR needs the IFR barrel replacement.

39. June 12, 2003EPAC Meeting39 Backup Slides

40. June 12, 2003EPAC Meeting40 Solid Angle Coverage … “Pure Barrel” represents ~1/2 of our muon acceptance. Backward Endcap is ignored – won’t be replaced. Region Lab frame polar angle (radians) Fractional  CM coverage (with  acceptance) Coverage relative to total Pure barrel 1<  lab < 2 0.413 (0.380)0.52 Barrel/fwd endcap overlap 0.7<  lab < 1 0.185 (0.170)0.23 Pure fwd endcap 0.3<  lab <0.7 0.194 (0.178)0.25 Sum 0.3<  lab <2 0.792 (0.729)1.0

41. June 12, 2003EPAC Meeting41 Circles indicate number of modules per sextant Composition of Module Arrays (small cell) (Widths in mm)  strips

42. June 12, 2003EPAC Meeting42 General Infrastructure for Q/C QC data and other relevant information collected by hand or, whenever possible, automatically with several DAQ stations. Common systems at PHT, Princeton, OSU, and SLAC. Labview will be used to write the DAQ software and design the interface. The DAQ stations will be operated by physicists on shift and/or PHT personnel. All DAQ stations will be on a wireless LAN. The DAQ station output will be simple text files. Local production database will be available on site. Data files will be transferred every day to an outside server to be imported in the official offsite LST database.

43. June 12, 2003EPAC Meeting43 Scope of Q/C Activities at PHT Barcode labelling Inspection of profiles  Mechanical  Graphite coating  Resistivity Measurement Inspection of jackets, endcaps, circuit cards Gas tightness (leak test) Wire check Wire-cathode distance measurement HV conditioning and plateau measurement Long range tests

44. June 12, 2003EPAC Meeting44 OSU HV Prototype (5 ch) 6kV Dc/Dc HV Op-Amp 15 V In 0-5 kV Out Current Monitor Protection Floating 5V Supply Current Monitor Outputs

45. June 12, 2003EPAC Meeting45 Prototype HV Connector (OSU) Integrated HV connection+capacitor Machined plastic prototype. Need to design connection between tube ground and strip ground planes. Production to be done in industry HV connector Endcap end

46. June 12, 2003EPAC Meeting46 Digitally, LST’s present themselves to DAQ like RPC’s Meetings held with Data Flow folks

47. June 12, 2003EPAC Meeting47

48. June 12, 2003EPAC Meeting48

49. June 12, 2003EPAC Meeting49 Preamp Tests at OSU Built pre-amps and receivers following Angelo’s design They work as expected. Some details (termination) being discussed between the engineers (Chuck, Angelo) Detailed studies using  Pulse generator  9x9 prototype tube (#17)  40 ft twisted-flat cable (Amphenol) Tested several configurations  Tube -> Receiver -> Oscilloscope  Tube -> Pre-amp -> Receiver -> Oscilloscope  Tube -> 40 ft cable -> Receiver -> Oscilloscope  Tube -> Pre-amp -> 40 ft cable -> Receiver -> Oscilloscope Preliminary conclusion: if noise levels at BaBar are comparable the preamp on the tube might not be necessary. Scope pictures

50. June 12, 2003EPAC Meeting50 Pre-amplifier tests HV Gnd 1nF 9x9 mmTube A receiver amp V out V ch V in+ V in V in- 40 feet of twisted pair AMP 425-3016-034 preamp scope triggered on tube signal

51. June 12, 2003EPAC Meeting51 Cable tests, N0 Pre- amplifier (OSU) HV Gnd 1nF 9x9 mm Tube A receiver amp V out V ch V in+ V in V in- 40 feet of twisted pair AMP 425-3016-034 scope triggered on tube signal Pulses make it down 40’ of cable in good shape!

52. June 12, 2003EPAC Meeting52 Ferrara

53. June 12, 2003EPAC Meeting53 BaBar IFR upgrade: LST readout status report 3.PROGRESS ON READOUT ELECTRONICS 3.aRecalling the outline of the LST-FE readout crate in the baseline version 610

54. June 12, 2003EPAC Meeting54

55. June 12, 2003EPAC Meeting55 LST Workshop Ferrara, Monday-Tuesday May 26-27, 2003 Proposed structure – we designate a chair for each session and a discussion leader for each topic. The discussion leader will begin with a brief (5-10 minute) summary of status and issues and lead the ensuing discussion; the chair will keep things moving along and will write down the action items. Ferrara Workshop, Monday May 26 Session I. – Tube/Module design. Chair – Mauro 0845 Identify commonalities, differences, plusses, minuses between large and small cell designs. – discussion led by chair 0900 Mechanical tolerances, robustness of tubes (large cell /small cell) --Vito 0915 Present state of endcap design --Federico 0930 Gas flow issues within tube and modules --Jim O 0945 HV connection design, issues --Angelo 1000 Phi Strip design, connections --Angelo 1015 Discussion 1045 Break Session II – Module construction Chair – Richard K. 1100 Module construction, mechanical -- Bill S 1115 Module construction, electrical -- Angelo 1130 Optimization of accessibility vs complexity 1200 Discussion, agreement on action items 1230 Break Session III – Z-strips and electronics Chair – Livio 1330 Z-strip design -- Angelo 1345 Z-strip mechanical issues, involving UCSD, installation 1400 Front-end Electronics issues -- Angelo --thresholds, in light of prototype results. --FEC’s on detector or in crates? 1430 Readout Crates -- Maurizio 1450 HV System -- Richard K. Can we decide on LVD vs OSU design? 1510 Slow controls (HV, temp, gas, etc) 1530 Break Session IV. Q/C at Pol.hi.tech, elsewhere Chair – Silvio 1600 Overview, list of procedures /tests (also listed on Elba agenda) -- Diego 1615 Apparatus, schedules -- Gigi 1630 The superbox – can it be everything to everyone? -- Bill S 1650 Relationship with Pol.hi.tech 1705 U.S. Participation at Pol.hi.tech -- Jim O. 1715 Q/C at module construction sites -- Jim O, Richard K 1730 Q/C at SLAC -- Charlie, Bob 1745 Break Session V – Preparation of EPAC Proposal Chair – Stew 1815 Status, weak parts, action items -- Livio 1830 WBS, Schedule, Assigning names to tasks -- Richard F by phone 1850 Break into discussion groups 1930 Adjourn to fabulous restaurant

56. June 12, 2003EPAC Meeting56 Ferrara, Tuesday May 27 Session VI – Gas system, Safety Chair – Charlie 0830 Review of requirements, SLD, RPC gas systems, -- Bob Defining elements of system -- Bob 0900 Gas System Schedule 0915 Safety overview, list of items -- Mauro 0930 SLAC safety approval procedures -- Charlie, Bill W? 0945 Duties of LST Safety Officer 1030 Break Session VI. [ Parallel sessions] 1100 A. Writing groups work on proposal B. Detailed issues of module/ tube design, integration, removal C. Develop safety organization 1215 Lunch Session VIII Prototype schedules, issues, results Chair – Roberto (remember we’ve already discussed this in Elba) 1445 Any new results, or conclusions since Elba 1500 Round-table discussion of prototype results from Pol.Hi.Tech, Ferrara, Princeton, OSU -- Are they consistent? -- Do we see adequate performance? -- What further tests? -- Can we widen plateaux? --Different gases? More sensitive electronics? … 1545 Pol.Hi.Tech construction status, schedules Roberto 1600 Small parts status, schedules, issues Mario 1615 Electronics for prototype module test 1630 Break Session IX. Conclusions 1700 Planning for SLAC LST workshop, week of July 14-18 1745 Brief Reports from Parallel Sessions, Proposal 1830 Review of Action Items by Session Chairs 1900 Adjourn

57. June 12, 2003EPAC Meeting57 E-field on the wire surface Small cell, 4700VBig cell, 5500V E(@center) = 198853V/cm E(off center) = 202603  E/E = 1.89% E(@center) = 205135V/cm E(off center) = 206931  E/E = 0.876%

58. June 12, 2003EPAC Meeting58 Anode wire diameter tolerance We can control the anode wire diameter within 1% of 100  m. Estimate the effect of this variation to the effective anode wire voltage: For big cell @ 5500V:  V = -44.6V For small cell @ 4700V:  V = -37.2V The difference between big cell and small cell is very small. E-field on the anode wire surface: Rc is the equivalent cathode radius, for big cell it is ~1cm, for small cell it is ~0.6cm. x is the anode wire radius.

59. June 12, 2003EPAC Meeting59 Dead time effect on counting rate The limited streamer signal can have after-pulse, which is generated by the photoelectrons due to UV photons hitting on the LST wall. From the drift time plot we can see if the dead time longer than 300ns, all first round of UV-photoelectrons would buried in the primary pulse. Drift time from walls