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A Low-Noise Broadband Cryogenic Preamplifier Operated in a High-Field Superconducting Magnet

The recently developed cryogenic Fourier-transform ion cyclotron resonance mass spectrometer (FTICRMS) has provided an opportunity for improvement in the limit of detection of FTICRMS by cooling the detection preamplifier to 4 K, thus reducing the thermal noise in the preamplifier. In this manuscript, we describe the development of a low-noise cryogenic preamplifier for FTICRMS and its performance in a high-field superconducting electromagnet. The preamplifier has a voltage gain of 250 with - 3-dB roll off at 850 kHz. The cryogenic preamplifier circuit has shown about 20 times improvement in signal-to-noise ratio, over the room temperature version.