Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)




Robert T Siegel


This experiment measured the time distribution of muonic hydrogen atoms which were formed when negative muons were brought to rest in H{dollar}\sb2{dollar} gas, containing Au target foils, at five pressures (750 mbar, 375 mbar, 188 mbar, 94 mbar and 47 mbar at 4.6 mm foil spacing). A Monte Carlo method is applied for deducing the initial velocity distribution, and preliminary results are obtained. The initial velocity distribution of {dollar}\mu{dollar}H atoms is reasonably well described as a 'Maxwellian' velocity distribution with a mean energy E = 3.4 eV. The corresponding muon mean capture energy is obtained: E{dollar}\sb{lcub}\rm c{rcub}{dollar} {dollar}\approx{dollar} 34 eV for {dollar}\mu{dollar}H atom and E{dollar}\sb{lcub}\rm c{rcub}{dollar} {dollar}\approx{dollar} 68 eV for {dollar}\mu{dollar}H{dollar}\sb2{dollar} molecules. We also find the negative muon capture energy distribution is exponential.;In addition, a significant improvement of the negative muon mean life {dollar}\tau{dollar} in Au is abtained in this experiment.: {dollar}\tau\sb{lcub}\rm Au{rcub}{dollar} = 69.716 {dollar}\pm{dollar} 0.144 ns. The "full decay curve fitting method" which we use in this experiment has an advantage over the previous method in three aspects: (1) We have measured the mean life and determined the time resolution {dollar}\sigma{dollar}(E) of a detector at a particular energy level; (2) We have determined the effective zero time of the decay curve; (3) We have provided a possible way to measure the mean life {dollar}\tau{dollar} when {dollar}\tau{dollar} is less than the time resolution {dollar}\sigma{dollar}(E) of the detector ({dollar}\tau{dollar} {dollar}<{dollar} {dollar}\sigma{dollar}(E)).



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