1. Flare mini review- part 2 April 19, 2005 Petros Rapidis1 We wish to continue and bring to completion the current effort of producing a credible design document in a timely manner. We are thankful for the engineering effort devoted to this to date and want to convince you that it should continue at an increased pace.

2. Flare mini review- part 2 April 19, 2005 Petros Rapidis2 Costs as of LOI and as of now Site and site infrastructure costs are not yet included

3. Flare mini review- part 2 April 19, 2005 Petros Rapidis3 Request for manpower for preparation of a design report has been submitted Included are : Tank analysis, including truss design, roof, chimneys, and thermal and mechanical aspects of cooldown, industrial safety code requirements. Argon supply, delivery, and purification, condensers and cryogenic systems. HV and HV field cage system. Wire chamber construction and signal feedthroughs Electronics design and packaging Data acquisition system Site development E S & H issues Project technical leadership

4. Flare mini review- part 2 April 19, 2005 Petros Rapidis4 Tasks and manpower needed for preparation of Flare design report Based on document prepared by A. Para in early February 2005 Manpower and materials required for an R&D effort were not included.

5. Flare mini review- part 2 April 19, 2005 Petros Rapidis5 We have given reports on specific topics and we are focusing on generating a design report with a chosen set of parameters. We are also conducting studies in parallel aimed at optimizing the final design choices.

6. Flare mini review- part 2 April 19, 2005 Petros Rapidis6 Demonstrate the superior physics performance of this detector Establish the efficiency for electron-neutrino e events as a function of the rejection factor for neutral current events containing a  °. i.e. further MC studies, with a more realistic detector simulation, which will include electronic noise and ionization loss to explore the ultimate limitations of this detector. In addition the development of reconstruction algorithms, and the development of automatic (non-scanning) analysis remain to be developed.

7. Flare mini review- part 2 April 19, 2005 Petros Rapidis7 Optimization of detector parameters: Stereo angle of induction planes (now set at 30 degrees) Wire plane layout (do we need a 7 th plane for ground?) Field cage layout – how many ribs Variation (tolerances) in wire placement and in cathode plane location (flatness) How do we handle the uninstrumented regions of the wire planes (i.e. density of wires in the unused triangles). Study of signal shapes, including effects of wire and stray capacitances These are simulation studies using tools such as Garfield, Maxwell, … Support from CD and AD will be required for this

8. Flare mini review- part 2 April 19, 2005 Petros Rapidis8 Technical Studies Goal is to validate claims of ultimate purity to be achieved in a industrially constructed vessel. Study of materials to be used, or encountered: Study of outgassing and contamination of liquid argon. Nickel steel, G-10, PEEK, lake water residue, weld detritus (raw materials) Connectors, pulleys, cables (1200 m 2 !!), instrumentation components Human detritus (hair, skin flakes, fingerprints ) It goes without saying that everything that goes into the detector will have to be demonstrated to be non-contaminating Given the fact that long residence times of humans are envisioned, mostly during the wire-stringing period, one cannot eliminate the possibility of such contaminants. It is also not clear how clean an industrial tank will be at the end of the construction process (which may include a hydrostatic test). We need to establish at which level construction residues and human contaminants present a problem.

9. Flare mini review- part 2 April 19, 2005 Petros Rapidis9 Study and prototyping of penetrations into the tank : Signal feedthroughs – chimney design HV feedthroughs Instrumentation feedthroughs Temperature, liquid level, pressure, flow (?), electron lifetime (purity monitors) Sampling feedthroughs – to extract gas/liquid for analysis and monitoring. We envision using argon purging around all seals to the extent possible; we will use welded seals to the extent possible.

10. Flare mini review- part 2 April 19, 2005 Petros Rapidis10 Study and evaluate purification techniques : i.e. adsorbers and such Oxysorb, Engelhard (Trigon) catalysts, NuPure, Air Liquide system There are two approaches here that one may investigate – A turn-key system, such as the one from Air Liquide (or others) requires the capability of testing such a system. A home built system using FNAL procured components involves some R&D We will also need to investigate systems with the capacity of removing large quantities of oxygen to be used in the earlier stages of purification. We are considering using an existing on-site tank (e.g. MP9 tank) to study these issues, in a more ‘realistic’ environment, which will include the possible effects of water cleaning and the introduction of possible contaminants that may be encountered in an industrial setting. (Note that the only large imaging LAr system to date (ICARUS) employed clean room procedures and evacuated their vessel.)

11. Flare mini review- part 2 April 19, 2005 Petros Rapidis11 Tools of the trade – the purity monitor … Moral of this picture: The purity monitor is a good indicator of performance.

12. Flare mini review- part 2 April 19, 2005 Petros Rapidis12 Tools of the trade – the purity monitor … Zap with light Cathode (-)Grid (ground) Q a /Q c =exp(-t/  ) V drift = L / t Gas – not liquid ! PAB data ! We need to make this work. We will need many of these ! Anode (+) 19 cm

13. Flare mini review- part 2 April 19, 2005 Petros Rapidis13 Another tool of the trade would be a (small?) chamber Advantages You see real signals – gain experience, boost morale and establish credibility ! Allows one to study electronics and zero-suppression readout schemes. Disadvantages Requires resources – more about this later

14. Flare mini review- part 2 April 19, 2005 Petros Rapidis14 Request to PPD for support (March 2005) for PAB activities The PAB setup will be used to gain some experience with the operation of purity monitors, to evaluate oxygen and other impurity absorbers, and to evaluate the properties of materials to be used. The request was for funds and manpower to : Complete and instrument the (first) PAB setup. Continue work with the purity monitor, and build two more such devices. Based on the response to this review we may have to revisit this modest request

15. Flare mini review- part 2 April 19, 2005 Petros Rapidis15 Setup at PAB – mostly recycled equipment. being built even as we speak !

16. Flare mini review- part 2 April 19, 2005 Petros Rapidis16 Setup at PAB – mostly recycled equipment. This system will be heavily used. We will need to, at least, duplicate it !

17. Flare mini review- part 2 April 19, 2005 Petros Rapidis17 Explore techniques to be used for wire chamber stringing and construction Construct small-scale models to try out stringing and tensioning schemes The present scheme involves pulleys and weights Can we string many wires together ? 250 000 x small number ($) = a big number of $ ! A segue into chamber construction logistics – a major concern that we are beginning to address Explore techniques for cathode plane and HV feedthrough construction Construct small-scale cathode plane models to try out some ideas. Issues – flatness, stiffness, support structures, construction scheme. Build models and test them at full voltage in liquid Argon environment. (note that HV feedthroughs will require full scale prototypes)

18. Flare mini review- part 2 April 19, 2005 Petros Rapidis18 Understand issues intrinsic to very long wire chambers (~30 meters) Electrostatic stability, Uniformity of wire spacing,Tensioning schemes Construct a full-scale model to try out all aspects of the wire stringing scheme – a tall area would be nice ! Noise issues due to large capacitances (can be simulated) and due to environment (pickup and microphonics – not as easy to simulate)

19. Flare mini review- part 2 April 19, 2005 Petros Rapidis19 Building prototypes An issue that has been the subject of spirited internal discussions. We are soliciting your advice on this ! a.Small prototypes : 0.1 to 2 cubic meters ( say up to 3 tons Ar) Advantages You see real signals – gain experience, boost morale and establish credibility ! Allows one to study electronics and zero-suppression readout schemes. Disadvantages Requires resources.

20. Flare mini review- part 2 April 19, 2005 Petros Rapidis20 b.Large prototypes : 100 to 1000 tons, and maybe a tall one (30m high)? Pro: Such devices allow one to test many of the issues involved in building the large detector. One can try to commit all the ‘sins’ here and find problems and solutions. In addition one can operate a substantially sized subset of the final purification system. Such devices, can be used as a near distance detector, but will not be optimized for such a purpose. Query: Is it the case that the issues of building a large detector are tractable engineering issues and their implementation in the final detector is standard engineering extrapolation, and, ipso facto, one does not need prototypes? There may be individual technical issues, but can they all be studied with specific individual prototyping? Con: (1) People, as well as money, will need to be devoted to such an effort and this will compete with, detract from, and delay the main tasks of designing, obtaining approval, and building the large detector. (2) There is a significant cost of such prototypes, due to fixed ‘end’ costs. We expect costs of ~ 2M$ to ~ 5 M$ or more depending on the size of the prototype.

21. Flare mini review- part 2 April 19, 2005 Petros Rapidis21 Develop a plan/design towards a 50 kTon detector, with the present design parameters. The final choice of detector size remains an open question; it will require input from many quarters (us, you, lab management, funding agencies, …). The 50 kTon design can be naturally scaled to a smaller size. Continue experimental studies to understand the technical issues of a LAr detector. Develop and refine the analysis and simulation programs. Our current plan is:

22. Flare mini review- part 2 April 19, 2005 Petros Rapidis22 Massive electronic imaging detectors provide a new modality needed for experimentation in high energy physics. We believe that a large LAr TPC is indeed such a detector. As such its introduction is somewhat akin to the introduction of large devices in the past, such as the bubble chamber, the large wire chamber systems, the silicon strip detectors. These devices, which in their time revolutionized the field, were brought to fruition by the significant involvement of the major laboratories. Such an institutional commitment is part of what we are requesting. Similarly, LAr imaging will revolutionize many aspects of our field. We have focused on the off-axis neutrino use of this device. But there are other uses: smaller experiments (see next talk by Bonnie Fleming), studies of proton decay, supernova neutrino detection, neutrinoless double beta decay, that can greatly benefit from this technology.