Liquid Argon TPC R&D for MicroBooNE and DUSEL

1. LArTPC R&D for MicroBooNE and DUSEL Hucheng Chen Apr. 2nd Omega Group Meeting • Outline • Liquid Argon TPC (LArTPC) for long baseline neutrino physics and nucleon decay searches • LArTPC Challenges • Readout and Cryogenics Front-End Electronics • MicroBooNE R&D • Electronics Readout R&D beyond MicroBooNE (DUSEL)

2. What is Liquid Argon Time Projection Chamber? • Unique detectors, true “electronic” bubble-chambers. • High precision measurements combined in one technology : • Tracking and Imaging (voxel size limited by diffusion) • Precision Calorimetry • Particle Identification (dE/dx meas. on the collection wire plane) H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

3. Why LAr TPC detectors for neutrino and nucleon decay physics? • Proton decay search • Sensitive to other decay channels (e.g. p  nK+) • Extend sensitivity beyond SK limits with >5kton detectors • Neutrino oscillation physics • Significantly more sensitive (~x6) than WC detectors (i.e. smaller volumes for same physics reach) • More powerful background reduction ne H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

4. LAr TPC R&D Challenges Key issue is feasibility of scaling in size • before reaching the fundamental limits in terms of the signal-to-noise, • and technological limits in terms of the readout complexity and cost Indeed many technical challenges (several are entangled …) • Cryogenic Vessels: • Design, material, insulation, non-evacuatable • Underground Detector Integration: • Safety, installation, cryogenics service location, costing… • LAr Purification: • Purification techniques for large, non-evacuatable vessels, materials • Purity of LAr in full scale detectors/Max. drift achievable • Readout: • TPC configuration • Electronics H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

5. R&D Challenges • Scalability to very large volumes (100ktons) is yet to be proved • ICARUS T600 detector at Gran Sasso (Italy) • Need a strong R&D program • Readout Electronics R&D in LAr Several different approaches and designs proposed in the past years LArTPC – FNAL: Modularized drift regions in one large (10-50kton) un-evacuated tank Large Wire planes and long interconnects GLACIER: Single Large Drift volume, readout in Gas-phase on the top. Charge and Light collection LAANDD: Single Cubic Module built by stacking in 2D sub-modules in evacuated vessel H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

6. Advantages of Cold Electronics • It allows more freedom in cryostat modules shape and configuration. • Modularization of the detector is built-in (many replicas with no-interconnect). • Overall better power management: • As an example, if we limit the sense wire length to 10 meters, the electron drift distance to 2.5 meters and the sense wire pitch to 3 mm, the number of sense wires (and readout channels) for a 3-coordinate readout will be ~25/ton in a large module. • Allowing for some latitude in the choice of these parameters, the power dissipation in the cold electronics can be limited to less than 1/4 of the cryostat heat load w. warm electronics • Advances in microelectronics, and in particular in low-noise-low-power electronics for detectors, have led us to propose an approach where the readout electronics with a high degree of multiplexing (by ~100 or more) will be inside the cryostat. This will allow greater freedom in the choice of the electrode granularity (length and pitch of the sense wires) and in the choice of the drift • The number of signal electrodes (sense wires) that can be read out is largely limited by the number of signal feedthroughs (cryostat penetrations) and complexity of the signal cables - if most or all of the active electronic components are at ambient temperature outside the cryostat • Design compelled toward long drift distances, long sense wires and long cablesto bring the signals outside the cryostat. • The length of the cables (or optical fibers) after multiplexing becomes much less critical than with external warm electronics. • The cold electronics at the electrodes with moderate sense wire lengths and no cables between the sense wires and the amplifiers leads to superior signal to noise and detection sensitivity. • The signal-to-noise ratio (i.e., the detector sensitivity) suffers twofold, from the attenuation of the signal charge during a long drift and from the increased electronic noise due to the capacitance of very long sense wires and long cables. • The long drift distance leads also to very high purity requirements for LAr. Stacked detectors for large cryostats H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting 6

7. Advantage of Cold Electronics • Best performance (i.e. S/N) achievable reducing the capacitive load seen at the preamplifier input • Place the front-end as close as possible to the wire minimizing the connection lengths • Cold electronics: performance optimized at cryogenic temperature • Factor ~3 at least better than at room temperature • For energy and position measurements optimal shaping in the range 0.5-2ms • Parallel noise sources (disturbances on HV, wire bias, microphonic) 2 Phase R&D: • Discrete JFET @ T=120K for MicroBooNE • ASICs w. PMOS input device @ T=90K for beyond MicroBooNE tp H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

8. MicroBooNE • A 70 ton fiducial volume LAr TPC on the BNB at FNAL • Collaboration formed in 2007 • 10 univ+labs/50 phys+eng. • Under design phase and DOE CD-1 later this year • http://www-microboone.fnal.gov • Low energy phenomena and excess observed by miniBooNE • Precision measurements of “golden” nmCCQE channel: • Possibility of CCQE measurements from intrinsic ne • Background for oscillation searches: NCpo, photonuclear events • 2.5mt drift @ 500V/cm • 3 Readout planes • 2 induction planes (U,V at ±60° from vertical) • 1 collection plane (vertical wires, 2.5m long) • 30 PMT for T0 determination • Evacuable Single vessel containment • No expansion vessel (8% ullage) • Readout based on “cold” preamplifiers • JFET based discrete • 10,000 channels • Warm Feedthroughs • Bi-phase purification system H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

9. MicroBooNE On-axis BNB • 8 GeV protons on Be target • Focussing horn: p+, K+ • Decay channel 50mt • 450mt dirt • 2-3x1020 POT/year • 3-2 years running (6x1020 POT) Proposed MicroBooNE site • Off-axis NUMI • 110 mrad off NUMI target • 4x1020 POT/year H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

10. MicroBooNE Readout Electronics Cold Preamp. Motherboard JFET discrete quad preamplifier TPC Readout Board Intermediate Amplifier Board H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

11. Cryogenic Front-End based on JFET Late 80’s • Technology mature and available as of today • Reliability issues requires a careful choice of component and high-reliability assembly • Ceramic hybrid with co-fired traces and surface mount components properly tested • Several years of experience • Helios-NA34: • 576 preamplifiers • Operations: 4 years, multiple cool-downs • Failure: 1 • NA48: • Preamplifiers in LAr: 13,000 • Operated at very high voltage • Failures: ~50 because of a HV accident in 1998. Negligible failures after that • Always kept at cryogenic temperature 2008-2009 H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

12. Cryogenic Electronics Setup H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

13. JFET Preamplifier Noise In JFETs majority carriers in the channel are electrons CARRIER FREEZOUT: Donor levels are ~40-50mV below band conduction, so a further reduction of temperature causes more and more electrons to fall in their  donor energy levels. In CMOS the conducting channel in Enhancement mode is formed by inversion (energy band bending at the Si/SiO2 interfaces) At high doping concentrations mobility increases and reaches a max., then decreases due to impurity scattering as the temperature of the lattice is reduced compared to the electron temperature Bulk mobility increases as temperature is reduced. Transconductance also. H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

14. Beyond MicroBooNE: DUSEL H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

15. Beyond MicroBooNE: CMOS Cold Electronics R&D • Operating at LAr temperatures (~90K) • Multiplexed architecture • Multiplexing may be performed in two steps, analog and digital, at appropriate locations within the cryostat • MUX>100 • With highly multiplexed readout, cost vs. channel count curve flattens • Low noise, low power • Performance characterization as function of T of existing processes • Develop models for cryogenic operation to be used for subsequent design optimization H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

16. Simulation 130K ATLAS Micromegas Muon Upgrade Cryogenic Characterization Beyond MicroBooNE (cont.) 32-ch. ASIC for Compton Imager (NRL) sparse readout, multiplexing, logic H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting

17. Summary • LArTPC is a promising detector technology for neutrino long baseline experiments and nucleon decay searches • Main issue is the scalability to large volume detectors • Cryogenic electronics, closed to the detector elements is critical to ease scaling issues • MicroBooNE will be the first running neutrino experiment to use a specific implementation of cryogenic front-end • JFET preamplifiers have been characterized in temperature and perform as expected. • Readout and detector integration need to be closely optimized • A strong R&D program to develop a low noise, low power ASIC with high multiplexing factor is required and has just started. H. Chen - LArTPC R&D for MicroBooNE and DUSEL - Omega Group Meeting