Skip to main content
European Commission logo print header

DEVELOPMENT OF ON-LINE AUTOMATIC SYSTEM FOR THE MEASUREMENT OF ALPHA EMITTERS IN SOLUTION

Obiettivo

THE OVERALL AIM OF THE RESEARCH PROGRAMME WILL BE TO DEVELOP AND CHARACTERIZE AN "ON-LINE" ALPHA MONITORING SYSTEM FOR MEASURING ACTINIDE CONCENTRATION IN LIQUID STREAMS. THIS KIND OF MEASUREMENTS IS OF GREAT INTEREST FOR THE DETERMINATION OF NUCLIDE INVENTORIES, SUCH AS PU AND AM, ESPECIALLY IN THE CASE OF LABORATORY WORKING ACTINIDES OR PROCESS STREAMS FROM RADIOACTIVE WASTE TREATMENT PLANTS.

IN THIS CONTEXT, THE USE OF ALPHA MONITORING TECHNIQUE HAS THE ADVANTAGE OF HIGH SENSITIVITY, LOW DETECTION LIMIT (LESS THAN 10-5 CI/1) AND THE POSSIBLITY TO DISCRIMINATE ALPHA EMITTING ISOTOPES OF DIFFERENT ELEMENTS.

THESE ARE THE GOALS OF THE PROJECT:
- STUDY AND DEVELOPMENT OF A THIN FILM TO PROTECT THE WINDOW OF THE DETECTOR IN ORDER TO PLACE IT IN CONTACT WITH CORROSIVE LIQUIDS WITHOUT ALTERING ITS PROPERTIES AND WITHOUT SIGNIFICANT SPECTRUM DEGRADATION.
- IMPROVEMENT OF SENSITIVITY, PRECISION AND RELIABILITY OF THE MEASURING SYSTEM.
- REDUCTION OF THE CONTAMINATION EFFECTS ON THE DETECTOR WINDOW (MEMORY EFFECTS).
- DEVELOPMENT OF A MATHEMATICAL MODEL ABLE TO EVALUATE THE SINGLE CONTRIBUTION OF DIFFERENT ALPHA EMITTING ISOTOPES.
- DEMONSTRATION OF THE POSSIBLITY TO CARRY OUT A SIMULTANEOUS MEASUREMENT OF ALPHA AND BETA EMITTERS.
The aim of the research programme was to develop and characterise an online alpha-radiation monitoring system for measuring alpha-emitter concentration in liquid streams. The measuring system would have included a thin fim which, while protecting the detector window, allowed contact with corrosive liquids without being damaged and without significant spectrum degradation.
The hardness and the resistance to acid attack presented by hydrogenated amorphous carbon, suggested its suitability for use as a charged particle detector window coating. Having found the optimal conditions needed to obtain adherence of the hydrogenated amorphous carbon thin film onto the aluminium detector windows, the required characteristic of impermeability could not be achieved. In spite of all efforts (attempts focused on the optimisation of the deposition procedure) the tests conducted on a coated target placed in contact with nitric acid solution gave unsatisfactory results. Microfailures present in films are responsible for the coating film permeability.
Tests showed a very low influence of the coating film on the transmitted alpha particles. A mathematical approach for the complex alpha-energy spectra analysis was developed and tested on alpha-spectra produced by summing different degraded spectra.

The aim of the present research programme was to develop and characterise an online alpha monitoring system for measuring the concentration of alpha emitters in liquid streams. One of the main features of the measuring system is a thin film which protects the detector window. This allows contact with corrosive liquids without damage and without significant spectrum degradation.

The hardness and the resistance to acid attack of hydrogenated amorphous carbon allows it to be used as a charged particle detector window coating. Having found the optimal conditions required to obtain the adherence of the amorphous carbon thin film on the windows of the aluminium detectors, it was not possible to attain necessary impermeability.

A mathematical approach for the complex alpha energy spectra deconvolution was developed and tested on alpha spectra produced by summing different degraded spectra.
1. ASSESSMENT OF THE CHEMICAL/PHYSICAL PARAMETERS CHARACTERIZING THE FILM, NAMELY IMPERMEABILITY, RESISTANCE TO CORROSIVE LIQUIDS AND TO ALPHA RADIATION.
2. REALIZATION OF FILM DEPOSITION ON DIFFERENT DETECTORS.
3. INVESTIGATION ON THE ALPHA ENERGY DEGRADATION EFFECTS DUE TO THE FILM.
4. REALIZATION OF A MEASURING HEAD FOR ALPHA MONITORING AND ITS OFF-LINE CHARACTERIZATION.
5. DEVELOPMENT OF AN ON-LINE CIRCUIT INCLUDING THE AUTOMATIC SYSTEM FOR MEASUREMENT CONTROL AND DATA ELABORATION.
6. DYNAMIC CHARACTERIZATION OF THE MEASUREMENT SYSTEM FOR PERFORMANCES EVALUATION.
7. DEVELOPMENT OF A MATHEMATICAL MODEL ABLE TO DETERMINE THE PARTIAL CONCENTRATION OF EACH ALPHA EMITTER (SPECTRUM DECONVOLUTION).
8. FEASIBILITY STUDY AND EXPERIMENTAL TESTS OF A SYSTEM FOR THE SIMULTANEOUS AND INDEPENDENT MEASUREMENTS OF BOTH ALPHA AND BETA ACTIVITY IN SOLUTION.

Argomento(i)

Data not available

Invito a presentare proposte

Data not available

Meccanismo di finanziamento

CSC - Cost-sharing contracts

Coordinatore

Ente per le Nuove Tecnologie l'Energia e l'Ambiente (ENEA)
Contributo UE
Nessun dato
Indirizzo
Via Anguillarese 301
00060 Santa Maria di Galeria Roma
Italia

Mostra sulla mappa

Costo totale
Nessun dato