In X-ray diagnostics (for example in computer tomography or mammography), X-ray tubes are used to illuminate the human body with X-rays in order to identify the cause or effect of diseases and injuries. The radiation exposure to the patient should be as low as possible and the image quality should be high.
To ensure reliable operation of the X-ray tubes, these tubes must be checked at regular intervals. As the precision of the tubes increases and radiation exposure decreases, the requirements for signal resolution and the lower detection limit of the monitoring measuring devices, the non-invasive dosimeters, also increase.
The newly launched Inkan project of the CiS Research Institute addresses the development of non-invasive dosimeters for measuring the radiation dose in medical diagnostics with X-rays. These dosimeters consist of a stack of silicon diodes and preamplifiers and should have a high signal-to-noise ratio. In contrast to conventional dosimeters, which are operated at room temperature, an operating temperature of around minus 10 degrees Celsius is aimed for here.
Particularly stringent requirements for medical products in the field of radiation diagnostics and therapy oblige manufacturers and operators of such systems to implement strict quality and safety monitoring. The filtering of very small signals from the background noise of the detectors and the amplifier circuit in particular requires a great deal of effort during calibration. An interdisciplinary team from various departments at the CiS Research Institute is tackling this challenge.
In a first step, double diodes are being designed and special passivations investigated. The aim is to reduce interference signals and prevent the formation of condensation on the diodes and electronics. For this purpose, the dosimeter is operated in an inert gas atmosphere or in a vacuum. At the same time, the structure of the stack and the comprehensive housing must ensure suitable heat flows so that a constant and low temperature prevails in the various levels of the stack.
The research and development work described is funded by the Federal Ministry of Economic Affairs and Climate Action (BMWK) in the research project “Innovative sensor cooling system for dosimeters” (Inkan).
Funding code: 49MF230044