Updated design for a low-noise, wideband transimpedance photodiode amplifier

Journal Article · Sun Oct 15 00:00:00 EDT 2006 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2351892· OSTI ID:20861235

Paul, S F; Marsala, R ^[1]

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1. Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543-0451 (United States)

The high-speed rotation diagnostic developed for Columbia's HBT-EP tokamak requires a high quantum efficiency, very low drift detector/amplifier combination. An updated version of the circuit developed originally for the beam emission spectroscopy experiment on TFTR is being used. A low dark current (2 nA at 15 V bias), low input source capacitance (2 pF) FFD-040 N-type Si photodiode is operated in photoconductive mode. It has a quantum efficiency of 40% at the 468.6 nm (He II line that is being observed). A low-noise field-effect transistor (InterFET IFN152 with e{sub Na}=1.2 nV/{radical}Hz) is used to reduce the noise in the transimpedance preamplifier (A250 AMPTEK op-amp) and a very high speed (unity-gain bandwidth=200 MHz) voltage feedback amplifier (LM7171) is used to restore the frequency response up to 100 kHz. This type of detector/amplifier is photon-noise limited at this bandwidth for incident light with a power of >{approx}2 nW. The circuit has been optimized using SIMETRIX 4.0 SPICE software and a prototype circuit has been tested successfully. Though photomultipliers and avalanche photodiodes can detect much lower light levels, for light levels >2 nW and a 10 kHz bandwidth, this detector/amplifier combination is more sensitive because of the absence of excess (internally generated) noise.

• OSTI ID: 20861235
• Journal Information: Review of Scientific Instruments, Vol. 77, Issue 10; Other Information: DOI: 10.1063/1.2351892; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CAPACITANCE
COLUMBIA HIGH-BETA TOKAMAK
COMPUTER CODES
DESIGN
ELECTRIC POTENTIAL
EMISSION SPECTROSCOPY
FIELD EFFECT TRANSISTORS
KHZ RANGE
MHZ RANGE
NOISE
PHOTODETECTORS
PHOTODIODES
PHOTOMULTIPLIERS
PHOTONS
PLASMA
PLASMA DIAGNOSTICS
PREAMPLIFIERS
QUANTUM EFFICIENCY
VELOCITY