Method for representing the spatial distribution of radioactive elements by means of a screen of the erasable phosphor type, and corresponding device

A method for representing the spatial distribution of radioactive elements of a radioactively labeled sample, by means of a screen of the erasable phosphor type, said radioactively labeled sample being placed near the screen and separated by a space from the screen in order to generate thereon a latent electronic image formed by .beta. radiation or primary electrons generated by the radioactive elements, said method comprising the steps of:

• converting said primary electrons into secondary electrons whose energy level lies between 1 eV and 5 eV;
• accelerating the secondary electrons to an energy level lying between 100 keV and 1 MeV by means of an electric field E applied in the space separating said radioactively labeled sample and said screen, and
• confining said secondary electrons subjected to acceleration in said space, so as to limit a lateral excursion of the accelerated secondary electrons and to form said latent image on said screen from said confined and accelerated secondary electrons.

A device for representing the spatial distribution of radioactive elements of a radioactively labeled sample, comprising a screen of the erasable phosphor type, and means for reading said screen with a laser beam, in which device said radioactively labeled sample is placed near said screen and separated by a space from said screen in order to generate thereon a latent electronic image formed by .beta. radiation or primary electrons generated by the radioactive elements, which device furthermore comprises:

• means for accelerating said primary electrons emitted by said radioactive elements to an energy level lying between 100 keV and 1 MeV by means of an electric field E applied in the space separating said radioactively labeled sample and said screen, and
• means for confining said primary electrons subject to acceleration in said space, so as to limit a lateral excursion (d) of these primary electrons and to form said latent image on said screen from the confined and accelerated primary electrons.

A device for representing the spatial distribution of radioactive elements of a radioactively labeled sample, comprising a screen of the erasable phosphor type, and means for reading said screen with a laser beam, in which device said radioactively labeled sample is placed near said screen and separated by a space from said screen in order to generate thereon a latent electronic image formed by .beta. radiation or primary electrons generated by the radioactive elements, which device furthermore comprises:

• a layer of secondary emission material which is combined with the radioactively labeled sample for converting said primary electrons into secondary electrons;
• means for accelerating said secondary electrons emitted by said secondary emission material to an energy level lying between 100 keV and 1 MeV by means of an electric field E applied in the space separating said radioactively labeled sample and said screen, and
• means for confining said secondary electrons subjected to acceleration in said space, so as to limit a lateral excursion (d) of these secondary electrons and to form said latent image on said screen from the confined and accelerated secondary electrons.