Introduction to ISS detector WG

1. Introduction to ISS detector WG Pasquale Migliozzi INFN – Napoli

2. Mandate of the WG(A.Blondel at the ISS-KEK meeting) Evaluate the options for the neutrino detection systems with a view to defining a baseline set of detection systems to be taken forward in a subsequent conceptual-design phase. Provide a research-and-development program required to deliver the baseline design  Funding request for three years of detector R&D 2007-2010 Some difficult choices will have to be made in order to most efficiently utilize the R&D resources that “might” become available

3. Working groups Water Cerenkov Detectors Kenji Kaneyuki, Jean-Eric Campagne Magnetic Sampling Detectors Jeff Nelson, Anselmo Cervera http://dpnc.unige.ch/users/blondel/detectors/magneticdetector/SMD-web.htm Liquid Argon TPC Scott Menary, Andreas Badertscher, Claudio Montanari, Guiseppe Battistoni (FLARE/GLACIER/ICARUS’) Emulsion Detectors http://people.na.infn.it/~pmiglioz/ISS-ECC-G/ISSMainPage.html Pasquale Migliozzi Near Detectors Paul Soler

4. Water Cerenkov

5. 65m CERN 65m 130km Fréjus 4800mwe The MEMPHYS Project Water Cerenkov modules at Fréjus CERN to Fréjus Neutrino Super-beam and Beta-beam Excavation engineering pre-study has been done for 5 shafts

6. Main results of the preliminary study • the best site (rock quality) is found in the middle of the mountain, at a depth of 4800 mwe • of the two considered shapes : “tunnel” and “shaft”, the “shaft (= well) shape” is strongly preferred • Cylindrical shafts are feasible up to : a diameter = 65 m and a full height h = 80 m (≈ 250 000 m3)  215 000 tons of water (4 times SK) taking out 4 m from outside for veto and fiducial cut 146 000 tons fiducial target • 3 modules would give 440 kilotons (like UNO) BASELINE • 4 modules would give 580 kilotons (HK) • with “egg shape” or “intermediate shape” the volume of the shafts could be still increased • The estimated cost is ≈ 80 M€ X Nb of shafts

7. Photodetectors • Baseline: photomultipliers • AIM: get the highest possible coverage to get the lowest possible threshold. Ideally, the same light/MeV as SuperK • The 20”PM is to expensive (12.6€/PE) compared with the 12”PM (7.7€/PE). The latter has also the advantage of a better timing and position resolution • Ongoing R&D on HPD together with PHOTONIS • Ongoing R&D for electronics (ASIC’s) and mechanics • AIM: low cost 200€/channel

8. Year 2005 2010 2015 2020 Safety tunnel Excavation Lab cavity P.S Study Excavation detector PM R&D PMT production Outside lab. Installation Det.preparation P-decay, SN Non-acc.physics Superbeam Construction Superbeam betabeam Construction Beta beam A possible schedule for MEMPHYS at Frejus decision for cavity digging decision for SPL construction decision for EURISOL site

9. Superbeam + beta beam together 2 beams 1 detector SUPERBEAMBETABEAM nm→ ne ne → nm nm → ne ne → nm 4 n flavours + K pure 2yrs 5yrs p+/p- 8yrs 5yrs 2 ways of testing CP, T and CPT : redundancy and check of systematics Recently a study on SB + BB + Atmospheric Neutrinos became available (see next)

10. The T2HK project • Tunnel-shaped cavity • Avoid sharp edges. Spherical shape is the best • Twin cavities • MFD/MTOT worse than single cavity. But… • Two detectors are independent. One detector is alive when the other is calibrated or maintained • Staging approach is possible • The Tochibora mine is considered as a candidate site: very good rock quality • Photosensors: PMT long-term stability proven, but too expensive. 13” HPD prototype under test at Tokyo U. Long term stability is an issue • Photosensors: time production too long. How to reduce it?

11. Possible experimental set-up Total cost must be similar to the baseline design. 2.5 deg. off axis 2.5 deg. off axis Distance from the target (km) JPARC 2.5deg.off-axis beam @Kamioka Off-axis angle

12. NB about 300 Oku-Yen should be included for the beam upgrade

13. Physics Reach of WC projects The ATM neutrinos are for free and should always be used in the calculations!!! For the MEMPHYS project the results are good, but could be excellent if both SPL and BB (plus ATM data) are exploited: COSTS! T2KK is not shown, but it improves the sensitivity to mass hierarchy

14. Summary table Detector Accelerator These results have been obtained assuming equal systematic errors (2%) NB The goal of a 2% sys error with a conventional beam is very ambitious.

15. My comments • The physics reach of WC detectors is well advanced and based on the solid bases of previous successful projects. Furthermore, it is very wide (SPL and/or BB, ATM, Solar, SN, proton decay,…) • Assuming the availability of the needed budget and no correlation with the T2K/Nova results, 2020 seems to be a realistic date for the start of data taking. In case of correlation a 5 years delay is possible. • Given that ATM neutrinos are for free and help a lot in solving degeneracies, it is mandatory to include them in all calculations • An issue is the R&D on photodetectors: • Costs should be reduced. HPD are promising. For the time being the better PE/MeV cost is given by 12” PMT • Production rate should be optimized. At present it lasts 10 years the production of all PMTs for 1Mton detector. Storage space could become a problem • MEMPHYS project: it seems that once the ATM  are included the SPL performs better than BB (assuming equal sys errors. Optimistic?). Maybe the BB adopted for the Frejus is not the optimal choice. Of course SPL+BB gives superior performances but it is very expensive.

16. Segmented magnetic detector

17. Magnetic field • Has not been investigated in any detail yet • Considering two options: • Iron sheets in between scintillator layers. • Parameters to study are thickness of each sheet and ratio of scintillator to iron. • More work needed to understand how to accurately simulate the field and perform reasonable reconstruction. • Air toroid magnet surrounding detector. • ATLAS magnet is a starting point in terms of scale. • Simulating 0.15 T field to start. • Will study physics parameters (P resolution, charge ID, etc) as a function of magnetic field

18. Status @KEK-ISS meeting • Past month spent in code development and testing. • Simulation now at a stage where they can be used for production of a high statistics sample for serious analysis. • Reconstruction still requires some work to fine tune track fit. • Need to define a list in order of priority of conditions to study and what results are required. • First list looks like: • Momentum resolution • Charge identification • Particle ID (dE/dx) • Two track separation • Jet angle and total energy resolution • Hadronic response • Neutron detection

19. Caveat (from A. Bross talk) Pattern recognition is “perfect” (or cheating!) as I use Monte Carlo truth to select the hits that belonged to the primary track (100% purity and efficiency). Once hits are selected, clustering, space point and track reconstruction proceed without the use of Monte Carlo truth information. Simple digitisation at the moment. Will need to decide what readout technologies to study in order to chose more appropriate values.

20. Is this Detector Scenario Credible? • Technology is not really an Issue • COST IS • Assume a 25kT all scintillator detector with air-core magnet (B = 1-3 kG) • Of course the study will also include magnetized Fe • Much larger Fiducial mass • Or could add non-active target in air-core design • Scintillator (Solid or Liquid) – No R&D issues • Cost (solid) - $100M • Segmentation as shown here gives » 7 X 106ch • $10/ch is possible - $70M • Fiber Cost – Assume high QE PD and high yield scint. Use 0.4mm fiber • $0.16/m ~ $16M (Very important optimization – 1 mm fiber is 6X the cost!) • $100M for magnets + infrastructure, etc • Total is something less than $300M • Not an order of magnitude more than what is acceptable

21. R&D areas • Photo-detectors • Already good work progressing on SiPM, MRS, even VLPCs. • Need High QE and reasonable gain • Potential readout chips already exist (integration) • Scintillator • Technology in place for the most part • Co-extrusion of WLS fiber with scintillator • Adjust plastic density (Z) by adding heavy element • Optimization of Scint+WLS fiber + PD • Cost/(pe detected) • Magnets • Natural extrapolation from Atlas? • Assembly and integration • Mild extrapolation from existing detectors • But some significant cost savings with new engineering approaches in a number of areas

22. My comments • The MC digitization should be developed according to the readout technology • A realistic pattern recognition has to be developed in order to address the reconstruction issues • The issue of how to magnetize the detector volume has to be addressed. This could be done together with the Emulsion WG although they need at least 0.5 T • This detector technology is ONLY suitable for the study of the “golden channel” • In the case of a “full active” detector, is it possible a synergy with the MECC technique? (see L.S. Esposito talk) • The cost is not an issue, but a more solid estimate should be performed

23. An ideal detector for a NuFact should Identify and measure the charge of the muon (“golden channel”) with high accuracy Identify and measure the charge of the electron with high accuracy (“time reversal of the golden channel”) Identify the  decays (“silver channel”) Measure the complete kinematics of an event in order to increase the signal/back ratio A magnetic field is needed! Two possible technologies: Liquid Argon TPC Emulsion Cloud Chamber

24. industrial study of large Tank 70 m diameter, 20 m drift = 100 kton of Larg shown to be feasible conceptually The LAr TPC

31. Thanks to A. Rubbia

33. My comments • Intensive R&D program going on • The proof of the long drift is a crucial milestone (in progress) • A detailed (magnetic, mechanical, thermal,…) of the coil yet to be performed • Very important the success of the proposed staged approach: 1 kton → 10 kton → 100 kton • Combine the efforts of the European and US communities • Full event reconstruction of neutrino events has to be shown: important to show the efficiency and background as a function of the neutrino energy • Define the needed magnetic field in order to efficiently (how much is driven by physics) measure the electron charge

34. MECC: the OPERA experience The detector is being constructed at the Gran Sasso Laboratory. Meanwhile several tests with charged particles and neutrinos at FNAL are under way An ECC brick is a self-consistent object. The whole detector is just an ensemble of bricks.

35. B=1T 3 cm Stainless steel or Lead Film Rohacell Electronic detectors/ECC “MECC” structure DONUT/OPERA type target + Emulsion spectrometer + TT + Electron/pi discriminator Assumption: accuracy of film by film alignment = 10 micron (conservative) 13 lead plates (~2.5 X0) + 4 spacers (2 cm gap) (NB in the future we plan to study stainless steel as well. May be it will be the baseline solution: lighter target) The geometry of the MECC is being optimized

36. Momentum and charge measurements

37. Questions raised during the ISS@KEK • Study the MECC performances by considering a lower magnetic field (< 1 T) • Optimize the target geometry and provide a reasonable estimate of the maximum affordable mass • Propose a baseline for the electronic detector (NB it should not provide accurate points, it serves only as time stamp) • Provide the energy dependence of the signal and of the background rates

38. My comments(details will be given by L. Esposito) • The emulsion scanning and the reconstruction programs are being developed by the OPERA Collaboration • It is possible to achieve the performances shown at the ISS-KEK meeting by using a 0.5 T magnetic field (the magnetization is similar to the one under study for the segmented magnetic detector: synergy) • How to magnetized a very large volume? • Given the expected interaction rate in each brick, a coarse electronic detector is enough (interesting synergy with the segmented magnetic detector) • Good results not only in the momentum and charge measurement for mip, but also for electrons • The needed R&D, but for the magnetic field, is not a real issue: a single brick is a self-consistent detector

39. e±, ±, ± • The R&D on the different detector techniques is in progress • The main issue is “how to magnetize large instrumented volumes” • Exploit as much as possible the synergy among different techniques (i.e. MECC and segmented magnetized detector) • Realistic estimats of the signal and background as a function of the neutrino energy • Realistic cost estimate not only of the detector but also of the accelerator complex

40. Near detector(taken from A. Blondel conclusion @KEK) Set-up a generic simulation of a near detector Define a series of potential detector geometries to run on near detector -- dedicated purely-leptonic detector for absolute fluy -- quasi-elastic , pi, pi0 detector with variable targets (a la T2K ND280) -- charm detector for Nufact Carry out physics studies needed for the ISS report: • Study flux normalisation through: • Use quasi-elastic and elastic interactions to determine neutrino spectrum • Reconstruct muon polarization from spectrum • Sensitivity for cross-section measurements: low energy? • Determination of charm: remember this is main background for golden channel! • ….suggestions ….

41. Conclusion • Systematics are a crucial issue. They seem to be the critical parameter in comparing “conventional beams” and BB operating with a 1Mton detector. Extremely important also at a NuFact • The water Cerenkov performances are solid, being based on real data provided by several experiments • Gigantic LAr detectors need a proof of principle: many activities under way • The technology for a segmented magnetized detector is not an issue. More simulation and a more realistic reconstruction program are needed to assess the physics reach • The MECC technique profits of the ongoing activity for the OPERA experiment. Possible (an welcome) synergy with other techniques for the electronic detector • How to magnetize large volumes and which is the maximum achievable field is a crucial item. Depending on this item the physics reach of a NuFact can strongly change. E.g. if only a “standard” magnetized iron detector is feasible, only the golden channel can be exploited!

44. Outlook • Study the performance of a stainless steel target • Detailed study of the way how to magnetize the detector • Define a realistic baseline for the e/p discriminator: its choice depends on the total target mass, the TT width (i.e. how many evts per brick), the costs, … • Finalize the electron analysis: the e/p separation and the charge reconstruction • Check the sensitivity to the “golden” (the muon threshold is at 3 GeV!) • A full simulation of neutrino events is mandatory in order to evaluate the oscillation sensitivity and provide the input for GLOBES • We plan to perform a first exposure of a MECC on a charged beam at CERN this year

45. considerable noise reduction can be obtained by gas amplification