SET ALLOWTOPICCHANGE = MuSunGroup

-- PeterKammel - 02 Jan 2008

Proposal Preparation Jan 2008 at UIUC

References

• current proposal version
• Peter's jan08 slides
• MuSun proposal page

Table of Contents

1. Beam Requirements
2. Safety Sheet
3. Physics Motivation (Peter: summarize USC discussion, email to Kuniharu)
   1. Calibration of Fundamental Astrophysics Reactions (Fred: neutrino impact)
      - L1A's influence on neutrino cross section not too large, but SNO small error might be too optimistic
      - Updated version of neutrino mixing parameter versus L1A contour plots desired
      - Fred will summarize this in a note
   2. Benchmark Electroweak Reaction on the Deuteron
   3. (Additional Impact)
      - This section shoul rather go to the Appendix in order not to have too much here, not to distract too much from the strong main goal(s)
4. Muon Capture on the Deuteron *(Peter: proposal)*
   - This section will be worked out by Peter and Dave with input from South Carolina group
   1. Theory
   2. Experiment
      - Overview of old experiments might need some rephrasing, less emphasis on very first experiments (1965, 1973)? Revision of figure 2 (axis interchange)
   3. Status of Basic Muon Capture Reactions
   4. L1A extraction
      - Collect all bits and pieces for the full error budget, table at the end after all terms are mentioned
5. Experimental Strategy (Peter: proposal)
   1. Overview
   2. Kinetics
      - Basic scheme under control and studied in parallel by several people - Tasks for proposal: Scan fit versus start time, Chi2 versus all parameters (Λd, Λqd, Λq, ...), study correlations of parameters, fit different distributions like capture, electron, fusion etc., do we understand the spectra at very early times
   3. Optimization of the Target Conditions *(Dave, Sara: fits and simulation)*
      - See kinetics studies - Needs also input from muon stop definition, energy deposition, influence of capture and fusion events to muon stop etc.
6. Experimental Setup
   1. Cryogenic TPC *(Peter: Main criteria, options, electronics, jan08, Peter&Peter: Clean room, R&D program at UIUC )*
      - Basic design as in Peter's slides, but details (like voltage and number of pads) will be fixed only during the design studies at UIUC / PNPI in the near future - Geometry has to be studied (different shaped pads, i.e. brick wall design) - Additional grid of induction wires for x resolution? - The cryo TPC construction is obviously a key point in the entire timeline, run plan but its design depends on several open questions (capture, fusion events, muon stop definition, resolution requirements).
   2. Cryogenics and Gas system
      - Basic design already shown at PSI by Sasha, work ongoing
   3. Detectors *(Tim: neutron detector program, X-ray detectors, w/o electron detector)*
      - Germanium detectors or NaI for X-ray tagging needs to be worked out in details but seems to be an option. Positioning close to the target possible (for sure with special runs w/o electron detector)?
      - Neutron detectors: maybe new design (what are the costs for new self made detectors)? Availability of DEMONS? Comparison of DEMONS with other neutron detectors from existing data. What can we say about Gamma / neutron separation, background level with existing data, needs analysis.
      - Special runs with no eDets but Germanium, neutrons etc. close by, study necessary changes (muon entrance counters) for upstream parking position of the eDet for these runs
      - Evaluate option for more permanent and accessible storage of MuCap in piE3 (reconfiguration of wall). Discussion with Robert and PSI local staff
   4. Electronics and Data Acquisition *(Fred: DAQ, cryo preamps, Tim, Valodja: BU WFD option)*
      - Full analog readout for TPC possible and reasonable (wrt data rates ~25 MB/s) with both Boston WFDs (use 2 8-bit FADCs per pad readout) or Louvain 12-bit FADCs. Needs discussion between experts to decide.
      - Option for low temperature amplifiers close to the pads has to be investigated (outgasing, heat load, deuterium diffusion into the chips).
      - DAC scheme similar to MuCap/MuLan strategy, data rates are under control, upgrade of existing computer power necessary but no main hindrance
7. Statistics and Systematics
   1. Statistics and Rates *(Peter: proposal)*
      - Slightly revised goal to obtain on the order of ~1.8x10^10 mu- and 0.9x10^10 mu+ (mu+ data set can be combined with MuCap mu+), no 'plan B' in the proposal
      - Explicit breakdown of the demanded weeks (2x12 weeks) by main mu-, mu+ and systematics + comissioning, setup etc
   2. Systematics (Detailed discussion)
      1. Clean Muon Stop
         - MC studies with respect to pad design and muon stop definition
         - Influence of fusion events on muon stop? Can cuts on such events at early times influence the e-time spectra, etc.
      2. Chemical Gas purity
         - Challenge because identification of capture events difficult with charged background from fusion
         - Density Φ = 5 and higher transfer rate lead to requirement of better conditions. However, the measurement of the impurity yield is the same compared to MuCap (Δλ/Y unchanged).
         - Impurity detection by tagging with X-ray has to be studied. Special topology of capture events (MuCap data might help)
         - Gas chromatography alone will not be sufficient as it might only give an upper limit (measured gas not in the cryo part)
         - Bernhard's observation of strong partial pressure dependence around 30K maybe useful (go to 27 K and freeze out more nitrogen). Can we test this at higher temperatures and concentrations?
         - Capture event detection is challenging at this point and needs further thoughts
      3. Isotopic Gas purity
         - Gas purification is working well
      4. Hyperfine transition + m3He capture
      5. Fusion Processes
      6. Hyperfine muon depolarization / muSR
         - Residual polarization in both states (doublet and quartet) needs inclusion into fits, will be added to kinetics studies (is it fully under control?). Experimentally addressed in stage 1
8. Appendix
   1. Additional impact / physics opportunities

Rediscuss Experimental Setup section

1. Measuring Program (Peter: proposal)
   1. Stage 1
      - Special detector setup with no eDet possible, comissioning of new TPC plus special runs / tests - 10 weeks in 2008 maybe too challenging (manpower, TPC construction plus eDet repair etc.), change to 6 weeks in 2008 plus immediate continuation after shutdown in 2009 maybe more reasonable, balance needed in pushing forward and our other tasks (like MuCap analysis)
      - Physics topics: Residual polarization, transfer rate. Doublet capture measurement not necessary at this stage (depends on run quality and analysis manpower)
   2. Stage 2
      - Cryo TPC operation, full setup
      - Doublet capture rate
      - Detaiols to be worked out later
2. Organization
   1. Responsibilities (only suggestion or due to shown interest):
      - FADC: Fred, Boston
      - DAC: Kentucky, Fred
      - Neutron: Tim, Fred
      - Germanium, NaI: UIUC, Fred
      - TPC: UIUC, PNPI
      - ....
   2. Budget Draft
   3. Time Line
   4. Request to PSI
3. First Beam Request
4. References
5. Appendix
   1. Additional Physics Opportunities (Peter: jan08)