Hi,
I had a look at Genya's plot of asymmetry vs. z for the
hydrogen target that he sent several days ago and tried
to fit the distribution to calculated values of the
product of atomic polarization and atomic fraction vs. z.
I assumed that polarization does not survive in the
molecules, that the value of 0.08 for the fraction of
initially unpolarized nucleons in the deuterium target
can be applied to the hydrogen target. I included the
distribution of wall collisions for a uniform surface,
assumed only transitions 1-4 and 2-3 for the wall
relaxation, included the field dependence of the
polarization in the individual hyperfine levels and
also sextupole rejection inefficiencies.
The attached plots show polarization and atomic fraction
in the left picture and their product compared to Genya's
data in the right. The plot cellpol_3a.jpg fit was produced
using the following values:
- recombination prob. gamma_r = 3.4e-3 +- 0.3e-3,
- spin flip prob. gamma_p = 1.0e-4 +- 2.0e-3,
- avg. atomic fract. alpha = 0.45
- avg atomic pol. P_a = 0.80
and cellpol_3b.jpg was produced using
- recombination prob. gamma_r = 1.5e-3 +- 0.3e-3,
- spin flip prob. gamma_p = 5.0e-2 +- 2.0e-3.
- avg atomic fract. alpha = 0.60
- avg atomic pol. P_a = 0.57
The main depolarizing effect is clearly caused by recombination
in the target. The scenario with little wall relaxation and
high atom polarization fits better to the data and suggests
strong recombination in the target but weaker wall relaxation
and high atom polarization.
The situation at the deuterium target might be similar and
one expects a significant rate of recombination. But the
target polarization will not be affected if the polarization
is conserved in the molecules.
Hauke
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Hauke Kolster MIT * Bldg 26-551 * Cambridge, MA 02139
kolster@mit.edu Tel (617) 253-2693 Fax (617) 253-9599
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