Institute of Isotopes Hungarian Academy of Sciences

Scope of activities

The institute pursues research activities in four main directions:

• development and application of nuclear methods for analysis,
• detection and quantitative determination of materials of nuclear origin,
• study of effects of irradiation, dosimetry
• study of surfaces and heterogeneous catalytic processes

Besides these, the institute occasionally contributes to the work of the relevant national authorities (primarily HAEA) by providing them expertise in the fields of nuclear safeguard and maintaining the national Registry of Radioisotopes (RADIUM).

Research aims and topics

Typical aims and results of activities on the four mentioned fields are listed below:

Development and applications of nuclear methods for analysis,

One of the institute’s basic research profile is the maintenance and application of the combined Prompt Gamma Activation Analysis (PGAA) and Neutron Induced Prompt-gamma ray Spectroscopy (NIPS) facilities at one of the neutron beam lines operating with the so called “cold” neutrons (~ 20 K) at the Budapest Neutron Centre. These unique non-destructive methods have been successfully applied for analysis of various substances, archaeological objects, geological samples. Another advanced application is the determination of the amount of hydrogen dissolved in metal catalyst particles under in operando conditions. An ongoing project is recently to construct the instrumentation for enabling the determination of the elemental distribution in three dimensions in the samples with a resolution of ca. 1 mm. (The scheme is shown in Fig. 1.)

The scheme of the NIPS and PGAA stations at one of the cold neutron beam lines of the Budapest Neutron Centre. Another nuclear method used at the institute is the in situ Mössbauer technique. Various substances have been studied so far (supported catalysts, porous ferri- and stannisilicates, etc.). Recently a development is in progress to establish an in beam Mössbauer facility where the Mössbauer source nuclei will be produced promptly by exciting the appropriate isotopes in the cold neutron beam. Improvement of the methods for detection of the neutron coincidence events is in progress, digital methods are being developed to improve the time resolution.

Detection and quantitative determination of materials of nuclear origin

Gamma-spectrometric methods have been developed and applied for the characterization of highly enriched uranium samples. The emphasis is laid on characterization of potential samples originated from illicit trafficking of nuclear materials. In particular, procedures for determining the ²³⁴U, ²³⁵U, ²³⁸U, ²³²U and ²³⁶U contents and the age of highly enriched uranium have already been tested.

A non-destructive, gamma-spectrometric method have been developed for uranium age-dating which can be applied to samples in any physical form and geometrical shape. It relies on measuring the daughter/parent activity ratio ²¹⁴Bi/²³⁴U at low-background. The method does not require the use of any reference materials nor the use of an efficiency calibrated geometry.

Development and application of novel methods based on the determination of isotope ratios of heavy elements with high resolution ICP-MS equipped with laser ablation unit. Methods have been developed for fast quantitative determination of isotopes of Pu and Am in environmental samples (soil, sediments, vegetation). By determining the appropriate ratios the original source of Pu (fall-out, power plant fuel, weapon, etc) can be identified. Another application is the determination of ²³⁰Th/²³⁴U ratio (e.g. in seized nuclear materials) from which the date of production can be specified. Further, the laser ablation has been proven a convenient non-destructive option for the sampling.

Migration of typical radioisotopes of spent fuel of NPP-s in geological media have been studied in order to estimate the retention properties of rock with particular regard to its perspective application as host media for high level nuclear waste deposition.

Study of effects of irradiation, dosimetry

Kinetics and mechanism of partial degradation of dye and pesticide molecules are studied during irradiation in waste water with an emphasis on the role of radicals.

Polymer monolyths are prepared from mixtures of monomers by irradiation techniques. They are functionalized and applied as sorbents.

Surfaces of porous polymers have been modified by electron-, gamma-, and plasma irradiation. The developed modified surfaces can be used for cultivation of cells.

Novel solid materials have been developed and applied for TL dosimetry in spaces exposed to high dose mixed (neutron and gamma) irradiation. Various dopants have been evaluated in CaSO₄ and alumina.

Research and development of aqueous and organic liquid systems have also been in progress for application to dosimetry in electron and gamma radiation processing (i.e. for facility characterization, product and process validation as well as for routine dose control in radiation sterilization of medical products, polymer processing, food irradiation).

Study of surfaces and heterogeneous catalytic processes

in the process of CO oxidation (including the preferential CO oxidation in hydrogen (PROX))

• Nanoparticles of gold have been supported on titania, silica and ceria. The metallic gold particles are stabilized and their properties are advantageously influenced by the oxide support.
• Pt and Pd have been supported on ceria. The stages of the reaction have been studied by in situ XPS and DRIFT techniques. The intermediate components in the reaction are proposed.
• The interplay with the complementary water-gas-shift (WGS) reaction has also been studied.
• Supported bimetallic catalysts have been studied in conversions of hydrocarbons. PtRh has shown synergism, Ge modified the properties of various surface sites in various PtGe catalysts, and alloy formation was detected in RhSn bimetallic systems.

Studies on environmental catalysis and activation of methane are also performed.

The presence and role of subsurface hydrogen in partial hydrogenation of alkynes to alkenes have been demonstrated on Pd in measurements with combination of the PGAA detection of hydrogen in the solid phase during the reaction.

Education activities

A number of senior research fellows participate in the post graduate education (seven researchers are members of the staff of various PhD schools of four universities). In correspondence, research work for PhD theses is regularly carried out at the Institute – 6-8 students are hosted in a yearly average. Graduate students are also hosted regularly.

Short IAEA courses have also been organized regularly at the institute to propagate the special experience collected on the characterization and the application of nuclear materials and radioisotopes.

Fields for cooperation

The research work on each of the four main directions has strong ties to the international scientific community. This can be illustrated by the statistics of the ISI publications: out of the communications coauthored by the research fellows of the institute c.a. 50 % is prepared within international collaborations.

A specific opportunity for cooperation is established within the EU FP6 NMI3 project: access is provided for various measurements at the cold neutron beam (PGAA and NIPS) facility.

The institute participates in the activities of various international organizations (ESARDA Workgroup for Non-destructive Analysis, and ITWG: International Technical Group for Combatting Illicit Trafficking of Nuclear Materials).

Besides these, the researchers of the institute are involved in a great number of various bi- and multilateral research projects.