Testing the radiation hardness of thick-film resistors for a time-of-flight mass spectrometer at jupiter with 18 MeV protons

The Neutral and Ion Mass Spectrometer onboard ESA Jupiter mission JUICE employs thick-film resistors (from ∼1 Ω to ∼1 MQ), screen-printed on ceramic elements, to realize high-voltage ion optical elements and decontamination heaters. Despite the relevant space heritage, these materials were never employed before in a radiation environment comparable to Jupiter's magnetosphere. With this study, we prove the suitability of these materials for the NIM instrument by means of irradiation up to ∼ 16–85 Mrad in vacuum with 18 MeV protons. To allow an accurate calculation of the dose, the chemical composition of the samples is determined by Laser Mass Spectrometry. Thanks to a custom-designed irradiation station, the temperature and the electrical parameters of the sample are monitored in real-time during the irradiation, or the sample can be subject to high-voltages representative of the operating conditions in space. All in all, the materials proved to be radiation-hard in the investigated dose range, with few exceptions where permanent damages occur.