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The article presents the results of the experimental research
on precision measurement of total stopping range and energy
deposition function of intermediate and heavy ion beams in cold
solid matter. The “thick target” method proves to
be appropriate for this purpose. Two types of detectors were
developed which provide an error of the total stopping range
measurement of less than 3% and of the beam energy deposition
function of about 7%. The experiments with 58Ni+26,
197Au+65, and 238U+72 ion
beams in the energy range 100–300 MeV/u were performed on
SIS-18 (Gesellschaft für Schwerionenforschung, Darmstadt)
in 1999–2001. The measured data on the total stopping
ranges for the above ion species in bulk and foiled Al and Cu
targets are presented. The investigation showed that there is
a noticeable discrepancy between the measured stopping ranges
and the theoretically predicted ones. Also, it was shown that
realistic ion energy deposition depends on the type of target
(bulk or foiled). Further investigation is necessary to clarify
Review of some research into laser thermonuclear fusion
carried out in Russian Federal Nuclear Center (RFNC-VNIIEF)
within the last several years is presented. The review
begins with a brief survey into ICF development in RFNC-VNIIEF
starting from A.D. Sakharov and S.B. Kormer's pioneer
proposals of the 1960s. The review concludes with the exposition
of historical background of the 10 TW ISKRA-4 and 100 TW
ISKRA-5 laser facilities creation and with the prospects
of the 300 kJ ISKRA-6 (λ= 0.35 μm) laser
development. The results of survey carried out at the ISKRA-5
facility are presented in the review. The high degree of symmetry
(nonuniformity < 3%) of irradiation of a DT-shell by the X-ray
emission made it possible to successfully conduct experiments
with the asymmetrical shells. The asymmetry was effected through
the asymmetrical Mg layers deposition on a spherically uniform
glass shell surface. The asymmetry impact on neutron yield and
the moment of neutron generation was investigated. The line
X-ray emission characteristics of the H-like and He-like
Ar, Fe, and Al ions were studied in another set of experiments.
Ar was doped into DT-gas, while Fe and Al were deposited
on the CH spherical hohlraums' inner surface. Development
of the Cherenkov radiation generator in which the electron
motion is actuated by the faster-than-light X-ray pulse
motion on the surface of a plane sample, being under voltage,
is reported. And in fine a brief description of experiments
carried out at the ISKRA-4 facility under the program of
turbulent mixing in plane multi layer targets is presented.
Spectrum and energy measurements of X-ray radiation
emitted by partially transparent Fe and Al plasmas have
been carried out for thin-layered inverted-corona targets
on the ISKRA-5 laser facility. The targets were plastic
spherical (2-mm diam) shells of 4.6 mm thickness having
0.25 mm Fe or 0.65 mm Al thin inner coatings. The energy
radiated in Heα and Lyα resonance
lines of Fe and Al ions was measured as well. Experimental
data and results of numerical calculations are compared.
Measured laser light to X-ray conversion coefficient has
been found to be essentially low, then calculated one for
both Fe and Al coated targets. Possible reasons for this
discrepancy are discussed.
The experiments to study the indirect drive targets'
dynamics in a highly symmetrical X-radiation field were
performed on the ISKRA-5 facility. This paper covered the
results of experiments with the targets in the form of
a Cu spherical hohlraum, the internal surface of which
is coated with Au, with six holes for laser radiation input.
In the center of the aforementioned hohlraum, a glass capsule
filled with D–T gas was placed. In several experiments,
the central capsule was coated with an ablator made of
plastic with a different thickness. This allowed us to
perform a series of experiments in which the different
compression degree of D–T fuel was achieved. The
analyses of experimental results revealed good agreement
between the latter and the spherically symmetrical hydrodynamic
Two shells with the diameter of 0.8–0.9 mm
and a wall thickness of ≅1 μm were produced at
the Lebedev Physics Institute for the experiments conducted
at the ISKRA-5 facility. The results of two experiments
with the aforementioned shells conducted at the ISKRA-5
facility with the use of an indirect-drive set up. In one
of the experiments, the diameter of the golden hohlraum
was D = 2 mm while in the other it was D =
4 mm. In these experiments it was observed to be ≅4
times the difference of the average laser intensity on the
hohlraum surface. The results of computational analysis of the
experiments are also presented here.
The first experiments to study the shell's
controlled asymmetry of capsule with DT-fuel in a highly
symmetrical X-ray field, which is obtained inside a spherical
hohlraum, were implemented. The asymmetry results from
the coating of one hemisphere with the additional layer
of material. The main goal of the experiment was to define
the value of the capsule asymmetry, allowing us to experimentally
obtain the neutron yield, which would be very different
from the yield obtained in the experiment with the spherically
symmetrical shell having the same mass as the asymmetrical
one. It was shown that the shell asymmetry of ∼50%
leads to the ∼(2–4) times reduction of the neutron
yield as compared with the symmetrical shell. 2D calculations
of the asymmetric capsule compression, using the MIMOZA-ND
code, were conducted. The calculations demonstrated that
the compression of targets, when exploding pusher regime
occurs has a complicated character. The computational neutron
yield, and the delay of the neutron generation time are
in good agreement with the experimental data.
The experiments measuring the density of DT mixture
compressed in indirect drive targets (X-ray targets) were
conducted on the ISKRA-5 facility. The density was determined
from the line broadening of H- and He-like Ar doped in
DT-gas as a diagnostic substance. A series of three experiments
with the X-ray targets having different shell thickness
of capsule filled with DT + Ar mixture were carried out.
In two of the three experiments, radiation spectra of Ar
were recorded and the density of compressed gas was determined.
The analysis of the experimental results for the X-ray
target with a 280-μm diameter and a 7 μm wall thickness
revealed that the density of the compressed gas may be
estimated as ∼1 g/cm3.
Since 1973, research into the problem of laser
thermonuclear fusion has been carried out at VNIIEF. For
this purpose, laser iodine facilities ISKRA-4 and ISKRA-5
with the peak radiation power up to 100 TW have been created.
In the present work, the main stages of these facilities
creation, approaches to the selection of the pumping sources,
working media, optical scheme, radiation focusing system,
the system of the pumping sources energy feed, laser radiation,
and plasma parameters diagnostics methods are shown. There
are also presented types of the targets, filled with DT-gas,
in which the high temperature plasma is formed and its
parameters are studied. Data on values of neutron yield,
of X rays in wide energy range, degree of implosion, and
data on mix of heavy and light layers of matter are presented
Measurements of spectral and energy X-ray characteristics
of almost transparent Fe plasma produced by laser radiation
inside the inverted-corona targets have been made at ISKRA-5
facility. The targets were spherical plastics cavities
with 2-mm diameter and 4.6-μm thickness covered from
inside with Fe layer 0.25-μm thickness. X-ray spectrum,
X-ray total energy, and the energy of a HeαFe
resonance line have been measured. Experimental data and
calculation results are collated.
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