Perspectives on an Electron Tracker for e Conversion The MECO Experience

1. Perspectives on an Electron Tracker for e Conversion The MECO Experience Ed Hungerford University of Houston Ed Hungerford - University of Houston

2. General Considerations • Resolution Minimal Detector Material – Thin, Low Z Vacuum Environment Sufficient position measurements • Rates > 500 kHz single rates >>1000 Channels Need both timing (~1-2ns) and analog information • Dynamic Range Protons 30-40 times Eloss for MIP electrons Maintain High MIP efficiency Pileup can be a problems in the tracker and calorimeter • Low Power, Low foot print electronics Signal Transmission to the DAQ Noise and Cross Talk • Redundancy (Redundancy, Redundancy) ambiguous hits, dead channels, noise, accidentals, ghost tracks Ed Hungerford - University of Houston It’s not what you know that limits the result

3. Two tracker geometry options “Longitudinal” geometry with ~3000 3m long straws oriented nearly coaxial with the DS and ~23000 capacitively coupled cathode strips for axial coordinate measurement “Transverse” geometry with ~13000 1m straws, oriented transverse to the axis of the DS, readout at both ends Two readout options Digitizing inside the DS cryostat Sending analog signals through the vacuum walls to digitize remotely ProposedMECO Electron Tracker Longitudinal Tracker Transverse Tracker Ed Hungerford - University of Houston

4. Eight planes projecting radially outward from each vertex of the octagon (blue in the figure)30cm2~300cm An octagonal array of eight detector planes (red in the right figure) 30cm~300cm Each plane is constructed with 3 layers of straw detectors Blue straws have conductive cathodes and orange straws have highly resistive cathodes . Inductively coupled readout strips on both sides ~5 mm wide The whole detector would have ~3000 anode wires and >19000 cathode strips. Both the amplitude and timing information are readout from each channel. The detector operates in a vacuum environment. Construction of Straw Detector Longitudinal Straw Tracker Structure Cross Section of L-Tracking Detector Ed Hungerford - University of Houston

5. 54 planes - 60° rotation with respect to neighbors 13,000 channels of TDC and ADC readout of the Anode wires All straws conducting - 70 -130 cm length  5mm diameter - 15 (25)mm thickness One (x,y) layer per frame – Hit Position Resolution ~150 um 3 spare planes Transverse Straw TrackerStructure Straw Array Back (60 straws) Support Frame Open Space Straw Array Front (60 straws) Space for Electronics Manifold Ed Hungerford - University of Houston

6. Manifold Ed Hungerford - University of Houston • 05-30-09 • Ed Hungerford for the COMET collaboration • 6

7. Straw Tubes(Conducting) (M-S Angle)2 Contribution Kapton => 16.5 (27.5) x 10-5 Gas (C4H10)=> 2.3 x 10-5 Cu layer => 4.4 x 10-5 Anode W => 450 x 10-5 Construction Straws composed of 2 over-wound layers of 12 μm thick, 5000 Angstrom Cu coated Kapton 5 mm - diameter 68 to 112 cm long 25 μm Au coated W – 5% Re Sense wire 17 um may be possible Material warps by sputtering so must be annealed Ed Hungerford - University of Houston

8. Straw Tubes (Resistive) Simulated Induction Amplitude vs time Resistivity of Cathode walls 0.5 M - 1.0 M per sq Resolution of <1mm Conductive strip needed to bleed charge from beam flash Resistive straw composed of ~19m XC Kapton and [overwound by ~10 m H Kapton (how to ground?) or 2nd layer of XC] Must have 3 internal supports for 3m wire Alternative seamless straw - PEEK (1m) Ed Hungerford - University of Houston

9. Straw DeflectionMeasurements Deflection measured By height from a precision table Slide Clamps Ends Horizontally Pressure The Straws Twist, Elongate, and Expand under pressure Micrometer to measure expansion Tensioned by Weights Plane Lay-up Fixture Ed Hungerford - University of Houston

10. Longitudinal Tracker (Resistive Vane) Ed Hungerford - University of Houston

11. Leak Rates andRadiation Exposure Conductive Straws Ed Hungerford - University of Houston

12. Straw Expansion under stress Straw Creep (ΔL/L) -80 g (7 days) ~ 1.6 x 10-4 Ed Hungerford - University of Houston

13. Parameters for W wires Ed Hungerford - University of Houston

14. Wire Tension Wires Tensioned at 80 g No intermediate support Add 3% Re to stabilize Ed Hungerford - University of Houston

15. HV vs collected charge57 % Ar/ 43% C2H6 HV ~2 kV For operation Background 0.5 fc gain 5 x 104 Ed Hungerford - University of Houston

16. Drift SimulationTransverse Tracker Gas – 80 %CF4/20% C6H10 Velocity - 8.5 cm/μs Drift Time - 45 ns Trajectory Trajectory Wire Wire Ed Hungerford - University of Houston • 16 • 05-30-09

17. Simulations Simulated Charge Simulated Anode Preamp Signal 15 ns Filter Ed Hungerford - University of Houston

18. Muon Capture Particle Yieldas a function of Z m; p,2n x 10 m; p,n m; p Ed Hungerford - University of Houston

19. Simulated backgrounds Neutron Proton <10 MeV - Thermal >10 MeV Exp tail 2 gamma, 2 neutrons, 0.1 proton per μ capture Photon Ed Hungerford - University of Houston • 05-30-09 • Ed Hungerford for the COMET collaboration • 19

20. Readout Architecture(Internal Digitization) • On-Detector amplification and digitizing – events passed by optical fiber in serial to DAQ (Parallel transfer also works) • Electronics based on CMOS to conserve space and power (<50 mw/ch) • Mounted on the detector frame • This system has been prototyped and demonstrated in a proton beam • Rad damage is not a problem If analog signals were transmitted through the vacuum wall then it requires a ribbon cable bundle 5 cm thick placed around the inner wall of the DS cryostat and a power consumption of 150-200 mW/channel Ed Hungerford - University of Houston

21. EXAMPLE Readout Electronics WBS 1.3.4.3.7 Mounting for Transverse Detector • The readout electronics works for either tracker • The system is based on CMOS to conserve space and power • Mounted on the detector frame • The system has been prototyped and demonstrated • Rad damage is not a problem Ed Hungerford - University of Houston

22. FEB Cabling for Signals and HV Fused HV Flex-ribbon cable Through manifold to FEB – Signals an HV 15 ns LRC Filter/channel Ed Hungerford - University of Houston

23. Front End Tests Ed Hungerford - University of Houston

24. A front-end board was developed to test the ASD-4 and a driver board is used to adapt the LVDS output to our lab CAMAC TDC. The Digitizing Board was completed. It used Elefant (Babar) but an updated version was needed and designed to the protype level Front-end electronics design & test results Ed Hungerford - University of Houston

25. Specifications of Preamp Ed Hungerford - University of Houston

26. Scheme of FE ASIC • Baseline • Holder • Slow • Shaper • Analog Output • Preamp • Input • Fast • Shaper • Disc. • T-to-A • Timing Output • Threshold • Trimming • Time Walk • Compensation • System • Clock ASIC PreAmp • FE ASIC will have 8 channels. One of the channels is shown above. • Input signal is amplified by a preamplifier; • After that, signal is split into two arms; • One arm is amplified by a slow shaper (100-ns peaking time) for amplitude measurement; • The other arm is amplified by a fast shaper (10-ns peaking time); • The discriminator circuit is to compare the input signal with a trimmed threshold. The result is converted to an analog signal that is proportional to the interval between the system clock and the discriminator output. Ed Hungerford - University of Houston

27. On-Detector PipelinedDigitizer • Digitizer ASIC Design WBS 1.3.4.3.7.2 •  based on the ELEFANT ASIC used in BABAR (8 channels/ASIC) • Work done in collaboration with design engineers at LBL • Rescale ASIC to 0.25 m technology and 3.2 V interfaces • Solves identified problems with the ELEFANT design • Change clock frequency (20-60 Mhz) • Change from waveform sampling to time-slice integration • Increase ADC bits to 10 • ~5 s Latency, self or external triggered • 18 serial, 20 Mb/s optic data lines through the vacuum • Power Consumption 65 mW/channel (Power 1,650 W) Design (LBL Engineer) $518K; Fabrication (2prototypes) 2 x $45k; Preproduction samples $50k; Production and packaging $231k, Testing $42k => $931k + 37% contingency Ed Hungerford - University of Houston

28. Scheme of Analog Buffer ASIC • Buffer 0 • Buffer 1 • Buffer L-1 • Peak Detector Array • Cell • 0, 0 • Cell • 0, 1 • Amplitude • Output • Inputs from • FE ASIC • MUX • Timing • Output • Cell • 0, 15 • 4 • Ch. • Addr. • Pipeline Control and • Sparsification Readout Logic • System • Clock • Trigger • Reset • This ASIC follows the FE ASICs and provides analog buffers to temporally store the signals. The buffer length is latency of trigger signal from the colorimeter. • Peak Detector Array has peak detection circuits for each channel. It generates peak-found signal to latch the amplitude and timing information of that channel to the analog memory. • The Pipiline Control and Sparsification Readout Logic • Controls the write/read sequence of the buffers • Provides zero-compression readout logic Ed Hungerford - University of Houston

29. Beam Test Ed Hungerford - University of Houston

30. Summary of electronic development • The Digitizing Board layout is completed. Backplane designed with FPGA , buffers, and PCI driver completed. System tested for rate and efficiency Digitizing Boards Input 16 channels • A replacement for ELEFANT was designed to the prototype level Mother Board with FPGA Memory and PCI controller Elefant Chips (2 x 8 channels) • A front-end board was developed to test the ASD-4 and a driver board is used to adapt the LVDS output to our lab CAMAC TDC. Ed Hungerford - University of Houston FEB Board

31. Newcomer, et al Front End for ATLAS Straws Ed Hungerford - University of Houston

32. Ed Hungerford - University of Houston

33. Tracker Cost Profile Ed Hungerford - University of Houston • 33