Low-noise preamplifier

Schematic diagrams for radio-frequency (r.f.) electronics are shown in Fig. 5.2. The circuit in Fig. 5.2(a) is a simple heterodyne circuit. The pulse length is defined by the switch SI. The speed of this switch determines the minimum pulse length, and hence the minimum lens focal length, and hence the highest frequency of the microscope thus the limit to the resolution is ultimately determined by the highest useful speed of this switch. S2 is the single-pole-double-throw (s.p.d.t.) switch, and Al the low-noise preamplifier. The mixer is a device that takes two inputs, the radio-frequency signal and the...

All broadband spectra were amplified by a low-noise preamplifier with a dynamic range > 1,000, and a broadband main amplifier. The amplified time-domain signal is digitized by a 20 MHz, 9 bit Bruker ADC with 128 K words of buffer memory, and Fourier transformed by a Bruker array processor (128 K word FFT in 8 sec). 

J. Rosenstein, V. Ray, M. Dmdic and K. L. Shepard, Solid-state nanopores integrated with low-noise preamplifiers for high-bandwidth DNA analysis, Proc. lEEEINIH Life Science Systems and Applications Workshop, 2011, 59-62. G. Ferrari, M. Farina, F. Guagliardo, M. Carminati and M. Sampietro, Ultra-low-noise CMOS current preamplifier from DC to 1 MHz, Electronics Letters, 2009, 1278-1280. 

The incident X-ray photon is converted to visible light in the scintillation crystal, which then falls into the PN junction photodiode. Generated electron-hole pairs are collected at the junctions. Since the generated current is usually weak, a low-noise preamplifier is required. The voltage output is proportional to the energy and fluence of the X-ray incidence on the detector. 

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