Predictable Quantum Efficient Detector (IMAGE) Aalto University Caption PQED consists of a Brewster window (left) protecting the detector elements from impurities, adjustable bellows and the detector chamber itself. In order to further decrease uncertainties in measurement, the window was removed and the detector was protected from impurities using nitrogen flow. Credit Aalto University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.