212Bi-212Po alpha source for the calibration and functional testing of silicon detectors: Preparation and characterisation

Silicon detectors are widely used in space radiation dosimeter systems for measuring energetic charged particles. Calibration of such systems is usually performed with protons and heavier ions in high energy particle accelerators. For preliminary energy calibration and functional testing of silicon detectors, at any time during the development, an equipment producing a thin 212Bi-212Po alpha particle emitting source was designed and constructed. Our aim was to develop an alpha source with negligible self-shielding and short life-time in order to prevent the long-term contamination of the detectors with alpha particle emitting nuclides. In the present paper, a description of the method chosen, and the equipment developed are given. Estimates of the activity of the source produced was obtained from measurements with the RADTEL space radiation telescope under development in the Centre for Energy Research, Hungarian Academy of Sciences (MTA EK). It was also used to verify that the alpha particle emitting source is suitable for the preliminary calibration and functional testing of silicon detector systems. •An alpha radiation source is needed for preliminary energy calibration and functional testing of silicon detectors.•An equipment with an emanator was developed to produce a212Bi-212Po alpha source.•Electrodeposition technique is an eligible method for producing an energy calibration alpha source.•232Th isotope is beneficial for preparing an alpha-source since it has a very long half-life.•Dryers or filters can eliminate effectively the undesired water vapour so it will not affect the deposition efficiency.