hlab meeting 2006 8/28
DESCRIPTION
HLab Meeting 2006 8/28. K - beam momentum. K - + n -> L + p -. Both spin-flip and nonflip states should be produced. p K = 1.5 GeV/c : K1.8 + SKS. SMF: Muon filter to suppress K - -> m - n. SDC3,4: Large-size (2.0mx0.8m), fine cell (1~2cm). To be constructed. - PowerPoint PPT PresentationTRANSCRIPT
HLab Meeting20068/28
K- beam momentum
pK = 1.5 GeV/c : K1.8 + SKS
Both spin-flip and nonflip states should be produced.
K- + n -> + -
1.5 GeV/c
Beam and Setup
Beamline: K1.8 0.5x106 K-/spill at 1.5 GeV/c (9A) K/ >> 1
Spectrometer: SKS (modified) p ~ 4 MeV (FWHM) ~ 110 msr
Hyperball-J ~ 7% at 1 MeV
-
K1.8
K-
SDC3,4: Large-size (2.0mx0.8m), fine cell (1~2cm)
SMF: Muon filter to suppress K- ->-
SP0: Veto counters to reject K- -> -0To be constructed
Beam hits Drift chambers
Low momentum transfer ~ 0.1[GeV/c] Beam K- 1.5[GeV/c] Scattered particle π- ~ 1.4[GeV/c]
Beam rate ~ 500k/spill (700kHz)→580 kHz/wire @ DC sell size 20mm (w/Beam distribution σx=19.8[mm], S=(2π)1/2Aσ)
Beam Scatterer (SBS)
To scatter the beam by Multiple scattering!
Property of SBS
Large radiation length (X0)
Pb :0.56 [cm] →1.77°→ 92kHz W :0.35[cm] → 2.28°→ 72kHz Pt :0.31[cm] → 2.45°→ 64kHz(1.5GeV/c K-, 5cm thickness, 200cm flight path)
Simulation
Straight beam K- 1.5[GeV/c]DC Cell size 20[mm]SBS 5[cm]
DC rate
Simulation: 700kHz→98kHz→76kHz(Calculation: 700kHz→92kHz→72kHz)・ w/o particle decay, Hadronic interaction
Position dependency
Distribution: Gaussian200cm→300cm
DC rate
Decreasing ~1 8(0.82), 15(0.85), 11(0.89)%
Thickness 50mm→100mm
Decreasing ~ 29(0.71), 28(0.72)% ⇔ 0.71
目標 50kHz/wire @ cell size 20mm(Pb 5cm, Flight path 200cm → 92kHz)(W 5cm, Flight path 200cm → 72kHz) This value is consistent with simulation (98, 76kHz).
W/o particle decay (0.67), Hadronic interaction, Beam distribution
→Decrease DC rate
Simulation Plan
Beam distribution (u=dx/dz, v=dydz) π- contamination (pi/K=0.2) Hadronic interaction→To confirm DC rate
Background study
値段SBS 5cmX5cmX5cm Pb : ~ 0 円 ( その辺のブロック ) W : 10 ~ 20 万円 Pt : 4500 円 /g (d=21.1g/cm3) Rate Pb=1 → W=0.78, Pt=0.72