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This study aims to simulate the diffusion of μd (muonic deuterium) and determine the effect that deuterium concentration has on the observed decay rate, providing insights into the measurement's criticality and the importance of accurately knowing cd (deuterium concentration).
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μd Diffusion in Protium Brendan Kiburg UIUC Gatchina Meeting June 14-18, 2004 2nd Workshop on MUON Project
The μd’s are weakly influenced by the protium potential and diffuse quickly at our energies. • At experimental density, v ~ 10 cm/μs . • μd + p μd +p has RT minimum at ~1.7 eV. • This effect first seen for electrons scattering off of argon, krypton and xenon Problem and Goals Goal: Simulate μd diffusion to determine the effect deuterium concentration has on the observed decay rate. This will tell us how well we need to know cd and how critical the measurement is. Kiburg, Gatchina Russia
µd is Born : Tc, Td Tc > Td ? Get Scatter, Ts YES NO Td > Ts ? Fill differential histos to Ts YES CM kinematics NO Generate Scatter Angles Update Particle Position And Momentum Td >Ts ? YES END NO Update Decay Spectra E, Position, Time, etc… Kiburg, Gatchina Russia
BK PK, mucat Various Cross Sections Generated from Simulation Used to pick the next scatter '2->2 ' Deceleration mud+H->mud+H File 'mud_p.fcn' 'CP ' 5 Ec:T=300 1992 1981.287e6 938.272e6 1981.287e6 938.272e6 0.0 0.04 100. 1.000E-03 4.763E+01 3.772E-01 1.312E-01 3.284E-01 5.514E-02 6.659E-02 3.000E-03 7.485E+01 4.567E-01 6.134E-02 1.248E-01 8.244E-03 8.249E-03 1.000E-02 1.252E+02 4.851E-01 5.600E-02 4.406E-02 2.450E-03 9.282E-04 5.000E-02 2.154E+02 4.795E-01 1.450E-01 6.085E-02 7.545E-03 1.298E-03 0.1 243.45 0.4611 0.215 0.1141 0.0208 0.0043 0.3 226.46 0.3933 0.4205 0.3058 0.1034 0.0238 0.5 178.80 0.3073 0.5621 0.5393 0.2582 0.0648 1 102.17 0.0512 0.4266 1.1482 1.083 0.3302 1.2 90.82 0.0011 0.0718 1.2009 1.5083 0.4929 1.5 92.76 0.0671 -0.5941 0.8864 1.902 0.6874 2 133.3 0.3508 -1.1986 -0.007 1.7613 0.7574 3 320.9 0.6652 -1.0529 -0.8686 1.0186 0.6218 4 600.8 0.7661 -0.7231 -1.131 0.6161 0.5546 5 945. 0.8092 -0.4558 -1.2486 0.3715 0.5352 6 1347. 0.8329 -0.2468 -1.3273 0.2008 0.5477 7 1781. 0.8483 -0.0749 -1.3921 0.0621 0.5787 8 2248. 0.8583 0.071 -1.4468 -0.0605 0.6197 9 2777. 0.8653 0.1955 -1.4981 -0.1728 0.6702 10 3335. 0.8708 0.3034 -1.5506 -0.279 0.7303 12 4608. 0.8782 0.4787 -1.6579 -0.4784 0.8722 14 6095. 0.8857 0.6131 -1.7922 -0.6699 1.0585 Kiburg, Gatchina Russia
µd is Born : Tc, Td Tc > Td ? Get Scatter, Ts YES NO Td > Ts ? Fill differential histos to Ts YES CM kinematics NO Generate Scatter Angles Update Particle Position And Momentum Td >Ts ? YES END NO Update Decay Spectra E, Position, Time, etc… Kiburg, Gatchina Russia
The parameters of every µd were recorded every 10 ns for all living µd Kiburg, Gatchina Russia
µd is Born : Tc, Td Tc > Td ? Get Scatter, Ts YES NO Td > Ts ? Fill differential histos to Ts YES CM kinematics NO Generate Scatter Angles Update Particle Position And Momentum Td >Ts ? YES END NO Update Decay Spectra E, Position, Time, etc… Kiburg, Gatchina Russia
Angular Distributions 3 eV (CM Frame) 10 eV (CM Frame) Forward Scattering Small delta E Backward Scattering Large delta E Kiburg, Gatchina Russia
Ang Dist 2 Kiburg, Gatchina Russia
µd is Born : Tc, Td Tc > Td ? Get Scatter, Ts YES NO Td > Ts ? Fill differential histos to Ts YES CM kinematics NO Generate Scatter Angles Update Particle Position And Momentum Td >Ts ? YES END NO Update Decay Spectra E, Position, Time, etc… Kiburg, Gatchina Russia
The distance from the origin and Td Kiburg, Gatchina Russia
Energy at the decay time in the lab frame RT minimum ~1.7 eV in CM Kiburg, Gatchina Russia
Radial Distribution at Td Kiburg, Gatchina Russia
R BK: Time slices representing the decay radial distributions PK: Mucat result Kiburg, Gatchina Russia
The mud population, normalized for every time slice Kiburg, Gatchina Russia
The radial distribution is shown, without regard for Td Kiburg, Gatchina Russia
Decay times of all muD within given cylindrical rings Kiburg, Gatchina Russia
There are still many things to consider before strong conclusions can be made • Input information will be changed to actual distributions • Real detector geometry will be implemented • MC will be modified to produce data events for the analysis software • Zero extrapolations will be made Kiburg, Gatchina Russia
Eloss as a function of incident energy Kiburg, Gatchina Russia
Muonic deuterons wander through protium (Ramsauer-Townsend Effect). • Consider lowest order partial-wave expansion at low E • l=0 sin2l ; for l =180 then =0 E must remain low so only l = 0 matters ½ wavelength in the box, outside the same Kiburg, Gatchina Russia
µd with cylindrical requirement Kiburg, Gatchina Russia
Most µd have a significant number of scatters Number of Particles Scatters Per Particle Kiburg, Gatchina Russia