Monte Carlo investigation of imprisonment of resonance radiation with partial frequency redistribution

Vermeersch, F.; Fiermans, Veronique; Ongena, J.; Post, H A; Wieme, Willem

doi:10.1088/0953-4075/21/10/023

Cited by 18 publications

(17 citation statements)

References 5 publications

(5 reference statements)

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“…Holstein [l] has computed the effective lifetime for an infinitely long cylinder of diameter D where 7 is the natural lifetime and ko the absorption coefficient at the central frequency assuming a cylindrical geometry and a pressure broadened resonance line r e j f = r(~koD)"~/1.577. (2) This relation shows, that r e f f is proportional to D'/2 at a fixed gas pressure. Inspection of the fourth row of Table 1 reveals that there is a pressure dependent small variation of this relation.…”

Section: Lasermentioning

confidence: 83%

Effective Radiative Lifetimes

Lange¹,

Leipold²

1997

Contrib. Plasma Phys.

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Measurements of trapped decay rates for the xenon 146.9 nm resonance transition in the positive column of low current xenon discharges are reported. These rates, also called "effective lifetime of resonance photons", were measured in contrast to other authors in an active discharge by means of a laser produced disturbance in the density of the 6s[3/2)1-xenon resonance atoms at the discharge axis. The 146.9 n m radiation resulting from this temporary overpopulation was measured and then analysed for the determination of the trapped decay rates. The dependence of the measured quantities of tube diameter is discussed. A cornparision with decay rates obtained by other experimental methodes and simulations of resonance radiation trapping shows good agreement.

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Section: Lasermentioning

confidence: 83%

Effective Radiative Lifetimes

Lange¹,

Leipold²

1997

Contrib. Plasma Phys.

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“…The most interesting region of parameter space for comparing the analytical formula with experimental results is the most severely trapped region where PFR is important. Figure 2 is a comparison of experimental results on Ar I resonance at 106.7 nm by Vermeersch and Wieme [16] to the analytical formula. We found that using an absorption oscillator strength in the analytical formula of 0.062 for the Ar I 106.7 nm resonance line gave the best agreement with experiment.…”

Section: Comparison Of the Analytical Formula With Experimental Resultsmentioning

confidence: 99%

“…A positive column discharge almost always produces a spatial distribution of resonance atoms closely approximating a fundamental mode solution. An excellent and more detailed review of resonance radiation transport modelling was recently published by Vermeersch and Weime [16].…”

Section: Introductionmentioning

confidence: 99%

Analytical formula for radiation trapping with partial frequency redistribution

Lawler¹,

Curry²

1998

J. Phys. D: Appl. Phys.

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A highly realistic Monte Carlo code is used to simulate radiation trapping including effects due to partial frequency redistribution and with a spectral line profile dominated by natural (radiative) broadening resonance collisional broadening and Doppler broadening. Results from 294 simulations are used to determine the fundamental mode trapped decay rate in cylindrical geometry over a very wide range of parameter space including a factor of in gas density, a factor of 1000 in column radius, and a factor of 1000 in Doppler width. The fundamental mode decay rates are fitted to an analytical formula expressed in terms of three dimensionless parameters which can conveniently be applied to a variety of gases, column radii and Doppler widths.

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“…Specifically, it is well known that radiation trapping gives rise to self-reversal in alkali discharge lamps, as trapped photons spectrally diffuse from the center of the resonance line to the lineshape wings [7,8]. Therefore, in the lamp temperature range of 150 to 175 o C, we should expect to see some consequence of radiation trapping in the optical pumping rate that generates the atomic clock signal.…”

Section: Clock Signal Amplitudementioning

confidence: 99%

A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to Red-Mode Transition in rf-Discharge Lamps

Camparo

Mackay

2007

2007 IEEE International Frequency Control Symposium Joint With the 21st European Frequency and Time Forum

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In the vapor-cell atomic clock, long-term stability can be influenced by slow variations in the discharge lamp's output via the light-shift effect. Additionally, over a multi-year mission lifetime the lamp's aging can degrade its optical pumping efficiency. Understanding the mechanism(s) that drives these changes is particularly important for spacecraft devices, where the atomic clocks are called upon to function continuously and reliably for many years. Here, we consider the two well-known, but little studied, modes associated with alkali rf-discharge lamp operation: the ring mode and the red mode. Consistent with previous research, we find that the ring mode is best for optical pumping, and that the clock-signal amplitude degrades significantly when the lamp operates in the red mode. Examining the emission spectrum as the lamp transitions between these two modes, we show that the ring-mode to redmode transition is driven by radiation trapping within the lamp.

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Monte Carlo investigation of imprisonment of resonance radiation with partial frequency redistribution

Cited by 18 publications

References 5 publications

Effective Radiative Lifetimes

Effective Radiative Lifetimes

Analytical formula for radiation trapping with partial frequency redistribution

A Mechanism of Rubidium Atomic Clock Degradation: Ring-Mode to Red-Mode Transition in rf-Discharge Lamps

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