B. Scientific
Activity
1. Methods.
Researches
for obtaining discriminating methods for the registration and studies of the
heavy ions, with different energies and charges, by nuclear track detectors.
Cooperation with Joint Institute for Nuclear Researches, Dubna, USSR (nuclear emulsions, plastic detectors
and meteoritic crystals), Institute for Medico - Biological Problems,
Moscow, USSR, Institute
for Experimental Physics, Kosice, Czechoslovakia (plastic detectors) and Institute for
Nuclear Physics, Frankfurt/Main, FRG
(AgCl monocrystals).
2. Cosmic Ray Studies.
Cosmic
rays are currently studied from three points of view: astrophysics, high-energy
physics and radio- biophysics. The last aspect has come into attention related
to the beginning of the manned space missions.
a) Supersonic Transport Level (18 - 20 Km).
a1) Studies of the ionization energy loss
spectra of the cosmic heavy ions and the irradiation doses produced by the
disintegration stars of the particles with energies greater than 1 GeV, from
the galactic cosmic radiation.
First
measurements on Romanian supersonic planes by specially designed cassettes,
containing detectors for cosmic protons, heavy ions and neutrons.
a2)
Studies of the neutrino
oscillation.
The
NOTTE (Neutrino Oscillations with Telescopes during the Total Eclipse) experiment was a joint Romanian
– Italian project that intended to look after visible photons from the
possible radiative decay of solar neutrinos, during the total solar eclipse.
Automated
Pointing System for
space and airborne experiments in cooperation with:
Tested
during the Total Solar Eclipse in August 1999 (several supersonic flights on
MIG 29 jetfighter).
b) Cosmic space.
In
situ experiments carried
out aboard the following cosmic objects:
-
COSMOS satellites
(flight year):
690 (1974); 782 (1975); 936 (1977); 1129 (1979); 1514 (1983); 1781 (1986), 2044 (1989), 2229 (1993).
-
INTERCOSMOS 17 satellite
(1977).
-
SALYUT 6 orbital
station (1979) and 7 (1982 - 1983 and 1985).
-
SALYUT 6 orbital
station (1981) - flight
of the first Romanian astronaut, Dumitru Dorin Prunariu.
The
purposes of these experiments have been reached by obtaining new experimental
data concerning the cosmic radiation field, especially in the circumterrestrial
space:
-
fluxes;
-
charge, energy and energy loss spectra;
-
variations with the geomagnetic latitude;
-
variations along the solar activity cycle;
-
estimation of the radiation hazard for the crew.
The
study of the Earth Radiation Belt resulted in data about the integral particle
fluxes (MINIDOSE, INTEGRAL
and ASTRO 1
experiments), the
differential energy spectrum (ASTRO 1) and the flux latitude variation of Carbon, Nitrogen and
Oxygen particles with energies up to 100 MeV / nucleon (ASTRO 2).
The
spectrum of the cosmic primary electrons has been measured by the Romanian
experiment SEZ 10,
mounted on INTERCOSMOS 17 satellite.
2006 - Principal
Investigator of the ÒGROWTH AND SURVIVAL OF COLOURED FUNGI IN SPACEÓ – ÒCFSÓ
to be caried out on the International Space Station. The project is funded by the European Commission
within the sixth framework programme for RTD activities (2002-2006, Specific
Programme ÒStructuring ERAÓ support to Research Infrastructures). Project title:
SURE, the contract number:
RITA 026069 – European Space Agency, ESA and, for the on-ground
activities, by Programme for European Cooperating States, PECS, between Romania
and European Space Agency, ESA.
c) Meteoritic crystals.
Participation
at a large international cooperation (Russia, France, India, Yugoslavia,
Mongolia and Romania) for studying the charge spectrum of the very heavy
cosmic ions (Z > 50) from the galactic radiation. Due to their extremely low fluxes, these
particles may be investigated only by using very large exposure factors
(exposure time x surface), a condition that is well fulfilled by the crystals
from meteorites. The cooperation has used them as "detectors" that
had recorded the cosmic very and ultra heavy ions for millions years. The
results are very important in astrophysics, for studies concerning the
nucleosynthesis of heavy chemical elements, the acceleration processes, the
estimation of the matter in Universe, and so on.
3. Nuclear physics.
The
heavy ion radioactivity -
the spontaneous
emission of heavy ions from very heavy nuclides - was theoretically predicted, for the
first time, by a group of Romanian and German physicists in 1980.
1984
- beginning of the
experimental investigation of this new type of radioactivity in cooperation
with the Laboratory of Nuclear Reactions from the Joint Institute of Nuclear
Research, Dubna. By using the same kind of detectors as in space experiments,
plastic detectors, the spontaneous emission of Neon 24 nuclei from the
isotopes of Thorium 230, Protactinium 231, and Uranium 233 was discovered and
the upper limit of the branching ratios for the spontaneous decay of the
isotopes Neptunium 237 and Americium 241 by Magnesium 30 and Silicium 32
emission was set with the highest sensitivity achieved at that moment in the
world.
For
these results I was awarded the I-st Prize of the Joint Institute for
Nuclear Researches, Dubna,
and invited to write the chapter "Spontaneous emission of Ne 24 and
heavier ions" in
the three volumes monograph "Particle emission from nuclei", CRC Press Inc., Boca Raton, Florida,
USA, 1989.
The
author or co-author of more than 95 scientific papers and communications at the
international conferences and congresses.
My
results have been cited by many foreign authors, including the following
monographs:
1.
S. A. Durrani and R. K. Bull "Solid State Nuclear Track Detection.
Principles and Applications.Ó
International Series in Natural Philosophy, vol. 111, Pergamon Press, London,
1987.
2.
A. M. Marenny "Dielectriceskie trekovie detectory v radio - fiziceskom
i radiobiologhiceskom eksperimenty.", Energoatomizdat, Moskva, 1988.
3.
"Particle emission from nuclei",
Ed.Poenaru D.N. and Ivascu M., CRC Press Inc., Boca Raton, Florida, USA, 1989.
Dr.
Dumitru Hasegan