We have developed a very low noise preamplifier that meets the low-cost, high-density requirements for use with superconducting tunnel junction (STJ) arrays. The design allows the STJs'' bias points to be digitally set at the μV level. We then trace out noise versus bias curves under computer control and, by showing the correlation between this noise and detector energy resolution, establish the ability to automatically select optimum STJ operating points. Working with a 75 μm × 75 μm STJ with a Ta x-ray absorber, we achieved better than 7 eV FWHM at the 525 eV O-K line with about 2 eV coming from the preamplifier.
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机译：我们已经开发了一种超低噪声的前置放大器，可以满足与超导隧道结（STJ）阵列一起使用的低成本，高密度要求。该设计允许将STJ的偏置点数字化设置为μV电平。然后，我们在计算机控制下找出噪声与偏置曲线，并通过显示此噪声与检测器能量分辨率之间的相关性，建立自动选择最佳STJ工作点的能力。使用带有Ta x射线吸收器的75μm×75μmSTJ，我们在525 eV O-K线上获得了优于7 eV FWHM的效果，其中约2 eV来自前置放大器。
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