MECO R&D Progress

1. MECO R&D Progress Michael Hebert UC Irvine January 20, 2003 NSF RSVP Review

2. Notes • This is a summary of where MECO R&D efforts presently stand • The R&D plan going forward and MECO resource needs are left to my next talk • Tasks directly connected with the magnets will be discussed by Brad Michael Hebert, UC Irvine MECO R&D Progress

3. Overview Tracker Studies • Chamber prototypes at Houston & Osaka • Detector simulation at NYU and UCI • Straw testing at UCI Muon Beamline Development • Vacuum window conceptual design at BNL • Optimization studies at UCI • Muon stop monitor tests planned by William & Mary Calorimeter Prototyping at NYU Cosmic Ray Veto System (Not Shown) Prototyping at William & Mary Michael Hebert, UC Irvine MECO R&D Progress

4. Tracking Chamber Options • Two options under consideration (details follow) • “Longitudinal” (or simply “L”) Tracker that is the baseline design and meets the physics requirements, but is challenging to construct • “Transverse” (or “T”) Tracker appears simpler to build, but our ability to interpret candidate tracks in the presence of background has been unclear • R&D is focused upon the concern areas, e.g. the engineering feasibility of the L Tracker and reconstruction in the T Tracker • The “Tracking Chamber Advisory Committee” will • evaluate our understanding of both variants • determine what is needed to make an informed choice between them • recommend a choice to the Executive Committee Michael Hebert, UC Irvine MECO R&D Progress

5. Longitudinal Tracker Geometry: Octagon with Eight Vanes Active Elements: Straws: 2.9 m length  5mm diameter, 25 mm thickness – 2800 total Three layers per plane, outer two resistive, inner conducting Pads: 30 cm  5mm wide cathode strips affixed to outer straws 23200 total pads Position Resolution: 0.2 mm (r,f)  1.5 mm (z) Readout Channels: 26k each of ADC & TDC Michael Hebert, UC Irvine MECO R&D Progress

6. Transverse Tracker Geometry: 18 Modules of three planes each, 30° rotation per module Active Elements: Straws: 70 – 130 cm length  5mm diameter, 15 mm thickness – 12960 total One layer per plane, all straws are conducting Position Resolution: 0.2 mm (x,y) Readout Channels: 13k each of ADC & TDC Michael Hebert, UC Irvine MECO R&D Progress

7. Tracking Chamber Studies & Support • Studies • L Tracker prototype at Houston and Osaka using different straw types • Front-end electronics work at Houston that is largely applicable to either the L or T variants • Simulations of performance in the presence of backgrounds at UCI (L Tracker) and NYU (T Tracker) • Straw leak testing at UCI • Project Support • Houston for equipment and post-doc salary Michael Hebert, UC Irvine MECO R&D Progress

8. Longitudinal Prototypes at Houston • SP-1 has one layer of resistive straws and a removable pad layer. It was used to compare signals to equivalent circuit simulations to determine optimal straw resistivity • SP-2 was built in the three layer L Tracker configuration and installed with the fine pitch flexible cable for connecting the ASD-4 and other front-end electronics. It is planned to use this prototype for beam and cosmic ray tests. SP-1 SP-2 Houston: A.Lan, E.Hungerford Michael Hebert, UC Irvine MECO R&D Progress

9. Data From Prototype Chambers • Studies of charge distribution on pads, gas properties, and several amplifier options • Selected ASD-4 as the leading amplifier candidate and determined the optimal straw resistivity to be 0.5 – 1 MW/sq Anode Pad 1 Pad 2 Pad 3 Houston: A.Lan, E.Hungerford Michael Hebert, UC Irvine MECO R&D Progress

10. First Full-length Vane Prototype • We are constructing a full-length (half-width) L Tracker vane to study mechanical aspects of the design • Straws must be epoxied together for mutual support, but epoxy contraction on setting caused problems initially • We have obtained a more suitable epoxy that meets the need • First batch of resistive straws had substantial leaks Samples glued with a new technique have been obtained and early tests indicate the problem is solved, but detailed tests remain to be done at UCI 3m Plane Lay-up Fixture Houston: A.Lan, E.Hungerford Michael Hebert, UC Irvine MECO R&D Progress

11. Simulated Signals • A Pspice model was developed to understand • Shielding effect of cathode resistivity • Impedance matching of straw • Current return paths in conductive and resistive straws • Readout signal time delay • Model calibrated with prototype data Houston: A.Lan, E.Hungerford Michael Hebert, UC Irvine MECO R&D Progress

12. Tracker Electronics Conceptual Design • 26k signal channels, 500kHz/ch, 1ns resolution, 8 bit ADC range for 6 bit readout • Two ASICs on the front end, 64ch/FEB, 23 FEB/plane, 16 planes, 8 sections • Deadtimeless front-end design, 1GHz/chip recording rate, latency buffer 6.5ms • 16 ASD-4 Preamp, 8 octal (ADC + TDC) digitizer chip, with an FPGA data processor on front-end board for zero suppression and data packaging under trigger control • A section processor to repackage the data from FEB by parallel FIFO to serial output Houston: A.Lan, E.Hungerford Michael Hebert, UC Irvine MECO R&D Progress

13. RAM event buffer MUX and Output FIFO Local Bus 8  ADC Latency buffer Clock Trigger Time-stamp 8 TDC Logic control Elefant Digitizer Chip Redesign with LBNL • Original design for BaBar in 0.8 m is obsolete, have to use TSMC 0.35 / 0.25 m to rescale and upgrade this chip • Additional Benefits: simpler design and lower noise, power consumption, and system cost • Designer accomplished a training project-DLL design in 0.35 m technology at BNL last summer • Cooperation with original design group at LBL is under negotiation • Production cost estimate is $8-15 per channel Houston: A.Lan, E.Hungerford Michael Hebert, UC Irvine MECO R&D Progress

14. Seamless Straw Development • Chamber Prototype • Three layers of straws • Conductive wound center layer • Resistive Seamless outer layers • 10 straws per layer • 2 cathode pads on outsides • Seamless Straws • Thickness : 25 mm • Diameter : 5 mm • Material : Polyamide + Carbon • Resistance : 6 MW/sq • Advantages • No Adhesive • Thinner • Better uniformity of Thickness and Resistance • Less out-gassing and leakage in vacuum Osaka: Y.Kuno, M.Aoki, A.Sato Michael Hebert, UC Irvine MECO R&D Progress

15. KEK Test Beam Performance • Cathode Pad Resolution • Seamless Straw (4MW/sq) Resolution s = 0.4 mm at 60° • Spiral Straw (0.5MW/sq) Resolution s =1.1 mm at 60° • Design goal (s = 1.5 mm) is achieved • Seamless Straw Anode Performance • Drift Distance Resolution s = 70 mm at 60° • Efficiency > 95% except near walls • Design goal (s = 0.2 mm) is achieved Cathode Pad Resolution Spiral straw s(mm) Seamless straw Angle (deg.) Straw Resolution vs. Angle Osaka: Y.Kuno, M.Aoki, A.Sato Michael Hebert, UC Irvine MECO R&D Progress

16. Straw Leak Testing in Vacuum • Suitability of various straw samples for vacuum operation is being tested at UCI • Seamless straws and conducting wound straws tested OK • First round of resistive wound straws failed (off-chart below). New straws with a revised adhesive will be tested this month UCI: J.Popp, B.Christensen, C.Chen Michael Hebert, UC Irvine MECO R&D Progress

17. Longitudinal Tracker Simulations • 5  106 reconstructed conversion events using the “average material” tracker and detailed CDR field map • The intrinsic resolution is 180 keV • The acceptance is 19% for NBack / Nsignal = 0.05 • We have begun simulating detector timing signals and using this information to form clusters of correlated hits in each plane • Tracks are formed from combinations of clusters consistent with conversion e trajectory UCI: T.J.Liu, J.Popp Michael Hebert, UC Irvine MECO R&D Progress

18. Transverse Tracker Simulations • A Kalman filter method is used to identify track associated hits in the presence of background • Reconstructed conversion e- momentum Resolution = 0.12 MeV/c • 500k DIO events were generated (10 expected rate) • Three events found in search range > 103.6 MeV • Background = 0.3 event • Muon conversion signal with the same cuts is6.5 events for Br = 10-16 • Bkgd/Signal Ratio = 0.05 NYU: R.Djilkibaev, R.Konoplich Michael Hebert, UC Irvine MECO R&D Progress

19. Tracking Chamber Advisory Committee • Charge to the Committee (paraphrased) • Evaluate simulations and prototyping efforts, determine what else is needed to make an “apples-to-apples” comparison • Set a firm date by which additional studies (if any) must be completed • Determine which design has the maximum likelihood to meet the physics requirements without presenting insurmountable engineering difficulties • Committee Membership • Collaborators: Paul Souder (Chair), Jim Miller, Ed Hungerford, Yoshi Kuno • Seug Oh, Professor at Duke University • Experienced in hardware aspects of straws from SSC, ATLAS (current) • Recommended by Al Goshaw (CDF spokesperson) • Herb Greenlee, Staff Physicist at Fermilab • Leader of tracker software for D0, experienced in pattern recognition and other software issues • Recommended by Gene Fisk from D0 • Mike Hebert, Bill Molzon (ex officio) Michael Hebert, UC Irvine MECO R&D Progress

20. Calorimeter • The detector consists of four vanes of 500 high-density crystals each • Two possible choices for crystal material • BGO – Produces a great deal of light, but response is slow enough to necessitate altering the time structure of the proton beam. Expensive. • PbWO4 – Less expensive and much faster response, but requires cooling to produce adequate light output • Spanning these two options drives the 100+% contingency in cost Operation in a 1 T magnetic field requires avalanche photodiode (APD) readout R&D is currently focused upon testing small samples of crystals and APDs to determine their suitability Project funds are supporting materials and equipment at NYU for these studies Michael Hebert, UC Irvine MECO R&D Progress

21. Crystal and APD Testing • 3  3  14 cm PbWO4 crystal • Large area (13mm x 13mm) APD from RMD inc. • Hamamatsu (5mm x 5mm) APD used by CMS • Crystal / APD combinations are tested using cosmic rays inside a freezer to increase crystal light yield and APD quantum efficiency and limit APD dark current Crystal / APD Test Arrangement NYU: R.Djilkibaev, R.Konoplich, J.Sculli, A.Toropin, C.Musso Michael Hebert, UC Irvine MECO R&D Progress

22. APD Temperature Dependence • Test results for the RMD Large Area APD • Both gain, gain stability, and dark current performance improve significantly with cooling NYU: R.Djilkibaev, R.Konoplich, J.Sculli, A.Toropin, C.Musso Michael Hebert, UC Irvine MECO R&D Progress

23. Crystal Temperature Dependence • Test results for a PbWO4 crystal • Gain change in the APD is compensated by adjusting the voltage • Improved light yield is evident NYU: R.Djilkibaev, R.Konoplich, J.Sculli, A.Toropin, C.Musso Michael Hebert, UC Irvine MECO R&D Progress

24. Cosmic Ray Tests Comparing two APDs mounted to the same crystal to examine sums and differences of collected charge Cosmic muon Most Probable Value energy loss in the crystal is 35 MeV Difference Measurementyields Sum should have the same width but for the Landau tail in the cosmic ray energy deposition APD1 - APD2 APD1 + APD2 NYU: R.Djilkibaev, R.Konoplich, J.Sculli, A.Toropin, C.Musso Michael Hebert, UC Irvine MECO R&D Progress

25. LED Tests Similar tests using 430 nm LEDs scaled to produce the same pulse height in the APDs Sum and difference have same width Resolution close to that measured with muons Implied total resolution at 105 MeV is 3.3% APD1 - APD2 APD1 + APD2 NYU: R.Djilkibaev, R.Konoplich, J.Sculli, A.Toropin, C.Musso Michael Hebert, UC Irvine MECO R&D Progress

26. Resolution vs. Shaping Time • The impact of shaping time in the front-end electronics on the resolution is illustrated below NYU: R.Djilkibaev, R.Konoplich, J.Sculli, A.Toropin, C.Musso Michael Hebert, UC Irvine MECO R&D Progress

27. Cosmic Ray Veto Counter Prototyping • Using an adaptation of the MINOS scintillator design with wavelength shifting fibers embedded in surface grooves • We have tested several donated short pieces of MINOS scintillator with several options for WLS fiber and multi-anode PMTs • Extruded scintillator with three glued WLS fibers appears to meet the MECO requirements Neutron rate simulations suggest that we need 2 cm thickness, which exceeds the extrusion thickness recommendations, thus we are planning to stack two layers Extrusion run of full-length samples in MECO configuration this summer Project funds for materials and equipment W&M: A.Norman, J.Kane Michael Hebert, UC Irvine MECO R&D Progress

28. Vacuum Window R&D at BNL • The thin window that stops and separates the production and detection region vacua is an important interface • Significant engineering effort was needed to accommodate removing it in the CDR • Potential vendors will need a detailed interface specification based upon a conceptual design In December BNL C-AD began work on that conceptual design 1st milestone completed: window material is Kapton This is a $10k contract after 13 months of negotiations, but it’s proof of principle that we can get NSF money into the Lab via UCI BNL: D.Hseuh, D.Phillips, W.Morse, P.Yamin UCI: T.J.Liu Michael Hebert, UC Irvine MECO R&D Progress

29. Muon Beamline Optimization Numerous adiabatic adjustments have been made to the design of the muon beamline in order to minimize unwanted particles contributing to detector rates while maintaining acceptance: • Add a small beam stop downstream of the prod. target • Use a 1 mm stainless vacuum closure plate in the PS • Add twelve 60 mm thick copper foils inside the last collimator • Altering dimensions of collimators and absorbers • Simplifying the muon beam stop • As a result, predicted Tracker and Calorimeter rates appear manageable UCI: V.Tumakov, W.Molzon, A.Arjad Michael Hebert, UC Irvine MECO R&D Progress

30. Detector Supports & Installation • The detector support structure and installation procedures and the complicated region at the downstream end of the Detector Solenoid have been studied at NYU and BNL • This works defines several of the interfaces with the solenoids There has been no project funding support for this task as yet NYU: P.Nemethy BNL: W.Leonhardt Michael Hebert, UC Irvine MECO R&D Progress

31. Production Target Options • Radiation-cooled • Minimal material in proximity to the target to absorb pions and reduce MECO sensitivity • Significant engineering difficulties to overcome • High density materials provide compact pion sources but suffer from substantial thermal stresses • Low density materials have manageable stresses, but require extended, complex shapes which also reabsorb pions • Water-cooled • Modest engineering difficulties associated with handling coolant • Concerns about impact upon MECO sensitivity due to water jacket material absorbing pions • Not a critical path system, allowing time to pursue the most promising option first and fall back to radiation-cooled option if insurmountable difficulties are encountered Michael Hebert, UC Irvine MECO R&D Progress

32. Production Target Physics Simulations Simulations of design parameters with GEANT indicate that a water-cooled production target can meet the physics requirements Target Titanium Water GEANT Simulations of Muon Yield Small water channel & thin containment tube costs 5% muon yield Inlet / outlet pipes should be minimized – Further study required Radiation-cooled   All with 3 mm OD inlet/outlet pipes  Large inlet/outlet UCI: A. Arjad, W.Molzon, M.Hebert, V.Tumakov, J.Popp Michael Hebert, UC Irvine MECO R&D Progress

33. Production Target Hydrodynamic Simulations Concurrent simulations of water cooling hydrodynamics (Master’s thesis in Mechanical Engineering) demonstrate feasibility of the cooling scheme Target Center Target Surface 397 K Titanium Tube Inner Surface Water Water Inlet Target Surface 293 K UCI: J.Carmona, R.Rangel, J.LaRue, J.Popp, W.Molzon Michael Hebert, UC Irvine MECO R&D Progress

34. Target Prototype Tests Water cooling effectiveness is being demonstrated via prototypes • Pressure Drop vs. Flow rate tests completed • Induction heating at 10kW in the next month Comparison of Prototype Data with HD Simulations Two right-turns Tapered ends Actual pressure drop is lower than simulations predict UCI: J.Popp, B.Christensen, C.Chen, W.Molzon Michael Hebert, UC Irvine MECO R&D Progress