Polarization of the light from the 3P(1)-2S(1) transition in proton beam excited helium. Ph.D. Thesis; [target gas pressure effects]

The theory developed by Band to treat the dependence on foil tilt angle of the polarization of emitted light is applied to the special case of 2s−3p transitions in neutral helium.Received 7 September 1979DOI:https://doi.org/10.1103/PhysRevA.21.1061©1980 American Physical Society

Physical Review AMar 1, 19802 citations

Polarization of the light from the 3P(1)-2S(1) transition in proton beam excited helium. Ph.D. Thesis; [target gas pressure effects]

Martin S. Weinhous

Published Dec 1, 1973• 0 citations

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We have measured the effect of the transfer of excitation on the population of the

3^{3}D

state of helium. Through careful diagnosis of a proton beam passing through a long target chamber containing helium gas, we have been able to separate the various contributions to the light intensity from the

3^{3}D

state. Our measurements were performed at target-gas pressures roughly two orders of magnitude lower than those of previously reported measurements. We measure the summation of the excitation-transfer cross sections ${\ensuremath{\sigma}}_{c}(n)$ for the transfer from an

n^{1}P

state to the corresponding

n^{3}F

state times the branching ratio

{B}_{\mathrm{n}}

for radiative cascade to the

3^{3}D

state, and obtain $\ensuremath{\Sigma}{B}_{n}{\ensuremath{\sigma}}_{c}(n)=2.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$

{\mathrm{cm}}^{2}

. This measurement enables us to relate the excitation transferred to the

3^{3}D

state

{Q}_{T} (3^{3}D)

to the excitation cross section of the

4^{1}P

state $\ensuremath{\sigma}(4^{1}P)$. We obtain ${Q}_{T} (3^{3}D)=(1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15} {\mathrm{cm}}^{3})N\ensuremath{\sigma}(4^{1}P)$, an expression, which for the low pressures used in this experiment, is linear in the number density

N

Photoionization of He(n

sup 1

sup 3

P) atoms excited by polarized light