References - Bogoliubov Laboratory of Theoretical Physics - JINR

over the distance of ∼ 28 m between the start and three stop counters. The time-of-flight
resolution ∼ 0.2 ns allowed one to separate completely secondary protons and deuterons.
The numbers of protons detected at the focus F 6 in exposures with carbon targets of
different thickness and normalized to the monitor counts are shown in Fig. 2.
Here dark circles, stars and
crosses refer to the 123-, 83and
40-g/cm 2 -thick carbon targets,
respectively, and the light
circles correspond to the measurements
without the target
T 1. The values of these ratios
averaged for all the exposures
are shown by broken lines.
It is seen that the points corresponding
to different target
thickness are grouped in different
regions of the picture.
The scatter of the points exceeds
statistical errors that are
less than the size of the points.
The nain causes of this scatter
are 1)non-stabilities of currents
in the magnetic elements
of the magnetic-optical channel;
2) nonuniform distribution of
Figure 2: Ratios of proton counts to the monitor (M1b + M2b)
in the focus F 5fortargetsT 1 of different thickness: black circles
- 137 g/cm 2 , stars - 83 g/cm 2 , crosses - 54 g/cm 2 , light circles - 0
g/cm 2 .
the intensity of the extracted deuteron beam within the limits of the spill.
The values of the tensor polarization pZZ of the deuterons that passed through the
target T 1 were calculated according to expression (1) separately for each channel of registration,
and then they were averaged over the channels; the counts without T 1were
taken as σ0. The dependence of the values of the tensor polarization on the thickness of
the target T 1 found in the described run is shown in Fig. 3 by black circles. We note
that the given values are found by averaging the results of two independent data processing
procedures. Light circles show the results of the previous run [4]. The corridor of
errors appropriate to both series of measurements is shown with broken lines. The calculations
of the spin alignment of the deuteron beam after passage through matter within
the framework of the Glauber multiple scattering model were made in the work [8]. The
calculation results for the carbon target are shown in Fig. 3 with the continuous curve.
The measurements performed in June 2008 basically confirm the results of the experimental
observation of the spin filtering of deuterons at passage of the beam through a
layer of matter obtained in March 2007. In spite of the certain distinctions in the dependences
of the tensor polarization of deuterons pZZ on thickness of the carbon filter
ΔC measured in these two experiments, the fact that the deuteron spin alignment increases
with increasing ΔC proves to be true. The distinctions mentioned are caused by
imperfection of the monitoring system of the magnetic optics of the channel of the slow
extraction of particles from the accelerator.
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