Cafe neutrino meeting minutes (12/01/09)
Present: E. Benedetto, A. Blondel, F. Dufour, I. Efthymiopoulos, R. Garoby, C. Hansen, G. Prior, T. Stora, E. Wildner
Summary of the AHIP09 workshop (R. Garoby):
Outcome of the workshop summarised in the minutes of the sLHC meeting of November 24th. Include cost estimates that need to be cross-checked since manpower and overhead costs are not included here. Project X is broken down into two phases. In the first phase, a 2.6 GeV CW (Continuous Wave) linac which can be viewed as a quasi-independant facility for rare decays search. In the second phase, adding an accelerator to bring protons from 2.6 GeV to 8 GeV.
Outcome of the Fermilab AAC meeting (R. Garoby):
Presentation of Project X Physics opportunities by R. Tschirhart (talk linked from AAC web page). IC stands for Initial Configuration. In IC1 pulsed linac 8 GeV, ILC technology. IC2 is a 2 GeV CW linac plus beam chopping (slide 17). How can we tag the kaons with such low energy proton beam ? MARS15 (LAQSGM) simulations yields on slides 24-25. Need to carefully look at the background (pions...) in this region. Project-X phase 1 is strongly encouraged by the AAC. But does it make sense to continue with an ILC based technology for next development ? Could go to half the frequency. Second part of the beam acceleration is not trivial. If we have a 2 GeV beam in a RCS (Rapid Cycling Synchrotron) with an injection time of 4 ms because of the magnets cycling structure there is no flatness. Also accelerating with a linac up to 8 GeV is also very annoying, need a 20 ms long beam which is a technological challenge. For a NF this involve huge compression factors. For a muon collider, even more difficult, we have to go from 50 Hz repetition rate to 15 Hz and from 3 bunches to 1. The advantage of a RCS over a structure with two rings (accumulator + compressor ?) is not clear.
Summary of the IDS-NF meeting in Mumbai (A. Blondel):
Summary document of the Steering group (in preparation) presented. There is some push for a low-energy (4 GeV neutrinos) neutrino factory (LENF) that could be matched to the DUSEL baseline. No gain on the flux at lower energy but could gain on some higher-energy background. Probably 30% cheaper. There is still a price to pay at the detector level since this would require a fine grained detector. The ντ appearance channel would be definitively lost. When the cost estimate will be done for NF, the gain estimate with LENF with also be computed. Detector proposed for LENF can be a LAr or scintillator bars. Still need to be magnetised which would favor the scintillator technology. Discussion around τ detection. Threshold is 3 GeV but more realistic to consider 15 GeV for signal significance. For MIND detector reasonable to consider 100 kT far detector and use UNO as being the near detector. Need to look at near detector sensitivity for low-energy neutrinos (2 MeV). Near detector is used for cross-section measurements. Some of the NF proton driver parameters were revised such as the kinetic energy range (now 4-15 GeV) or the pulse duration. Plot of CP violation phase sensitivity for different neutrino facilities presented. Best reach for NF with baseline to Finland. Beta-beams sensitivity (EURISOL) seems to be a bit low. Need to be revised. DUSEL configuration considered was 2 MW beam with 300 kT WC detector. T2KK is the sensitivity that was most carefully evaluated (three detectors). Assuming T2KK gives us a number, what would be the next best facility that could be built ? Depending whether we want to look at mass hierarchy (need more matter effect) or not, can have different scenarios with a revised baseline length. The new beta-beams scenario (EUROnu) sensitivity is not as competitive. For 8Li, 2 GeV is the maximum energy. Need to look at what happens at 300 km with the EURISOL+SPL scenario. See what horn optimization could be done (Ilias/E. Gschwendtner to ask for horn configuration). Contact M. Mezzetto (M. Zito) for updating the plot.
Ions study for beta-beams (T. Stora):
Looking at 18Ne shortfall from FP6 study. Was considering 1 GeV proton as baseline or low energy 3He beam. Now looking at 70 MeV proton beam. Trying to avoid the MW region as it can cause problem with the target. Had a meeting in Grenoble (WP4 EUROnu) where the concept of molten NaF loop (800 degree C) are current nuclear industry standard and was investigated as potential target. Need to be transformed in a target that can produce an ion beam. At 70 MeV big dependance on cross-sections which are not well-known. Progess will be presented in a future cafe-neutrino meeting. Considering more 18Ne in the machine as the space charge is smaller. Regarding the time structure of the beta-beams ions, looking at the short-bunch from SPL still gives a too high duty factor. Given say, 20 bunches of 5 ns in 20 ms, with 5 times more in 5 times shorter bunches would it work ? No as the maximum that could be filled would be 12 bunches.
Neutrino wiki (F.Dufour):
A wiki containing information, useful documentation is being set up and can be reached from the EUCARD WP3 webpage under the link "Physics Wiki". It works as a set of fact sheets with questions relevant to the neutrino work and answers or documents containing answers to it. Input ideas are welcome. It can be read for anyone who has a CERN account. To be able to modify the page need to be an author (ask Fanny for permission). This is a Microsoft product and to be able to edit under firefox linux, one needs add-ons (information on what is need will be added on the wiki).
J. Strait is at CERN until Christmas shutdown, see if he would be available to come to the next neutrino meeting and give a talk on the U.S plans and DUSEL.
Monday December 14th 10:30 am