Measurement method for X-ray shielding effectiveness of enclosed shell

Background: Study of the ionizing radiation effects for semiconductor devices and integrated circuits is becoming more and more important for the improvement of their radiation hardening in microelectronics field due to the dose enhancement effects of X-ray. Experimental data of X-ray shielding effectiveness on outer shell can only be acquired by simulation calculation in the past. Purpose: In order to ensure the reliability of the electronics system inside shell in X-ray radiation environments, a novel method for measuring X-ray shielding effectiveness of enclosed shell is proposed, which can be established in laboratory. Methods: The generation of specific energy spectrum X-ray radiation field is designed and implemented to perform X-ray dose response calibration experiments using the LiF thermoluminescent dosimeter, which is chosen to fit the circumstance of enclosed shielding cavity and the narrow internal space. Based on the bremsstrahlung spectra of the X-ray generater, a target X-ray energy spectrum in real environment is imitated by filtering and multiple combinations. The dose response of LiF is measured under the irradiation of ⁶⁰Co source (1.25 MeV). The discrete semi-monochrome X-rays (20-100 keV) was established as the LiF energy response calibration X-ray sources by X-ray exciting fluorescence. The experiments of X-ray shielding effectiveness and dose contribution are carried out for sample shell, and dose effect experiments of scatter X-ray are performed on constructed spectrum. Results: The experimental results show that dose of scatter X-ray contribution can be observed significantly on the internal cavity. Conclusion: The method has been applied successfully on the measurement of sample shell, and the data of X-ray shielding effectiveness are acquired. It provides an experimental evaluation approach for X-ray radiation hardening technology. (authors)