An Accurate Low Current Measurement Circuit for High-Resolution Energy Spectroscopy Systems

Pierre Hypolite Bakoune, Evariste Wembe Tafo, Adolphe Moukengue Imano, Arlette Joelle Mouen Mouangue, Lucas Kana Kemgang


With the development of radioactive ion beam physics, heavy-ion beams have been applied to the treatment of deep-seated inoperable tumors in the therapy terminal of the Heavy ion Research Facility in Lanzhou (HIRFL) located at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). An accurate low current measurement circuit was developed to monitor the beam current at 10fA range. The circuit consisted of a low current high sensitivity I/V converter with a dynamic bandwidth. A low offset voltage precision amplifier and new guarding and shielding techniques were used in the I/V converter circuit which allowed as to measure current up to 10fA with a current gain of 0.43 V/fA and noise less than 50 fA. This paper will also show a T-network configuration which was used for boosting bandwidth.


Low beam current, I/V Converter, Operational amplifier, Bandwidth

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- Yong Zhang et al. “An improved forward travelling wave structure design for stochastic cooling at experimental cooler storage ring (CSRE), proceedings of the 2011 on beam cooling, pp.132-135.

- Jie Kong et al., “Development of multi-channel gated integrator and PXI-DAQ system for nuclear detector arrays”, Nucl. Instrum. Meth. Phys. Res. A 622 (2010) 215–218.

- Chao-Yang Zhou et al., “An accurate low current measurement circuit for heavy iron beam current monitor” Nucl. Instrum. Meth. Phys. Res. B 280 (2012) 84–87.

- V. Auzelyte et al., “On-line measurement of proton beam current in pA range”, Nucl. Instrum. Meth. Phys. Res. B 249 (2006) 760–763.

- L.M. Redondo et al., “A low-cost, accurate and non-intercepting continuous method for beam current measurements in a high-current ion implanter”, Nucl. Instrum. Meth. Phys. Res. B 265 (2007) 576–580.

- S. Riboldi et al., “A Low-Noise Charge Sensitive Preamplifier for Ge Spectroscopy Operating at Cryogenic Temperature in the GERDA Experiment”, INFN, October-November 2010, Nuclear Science Symposium.

- F.A. Levinzon, “Noise of Piezoelectric Accelerometer with Integral FET Amplifier”. IEEE sensors journal, Vol.5, No.6, Dec. 2005, pp.1235-1242.

-E. T. WEMBE et al., “Noise optimization of readout front ends in CMOS technology with PS circuit”. Asian Journal of Applied Sciences, Vol.2, N°5 (2014), October 2014, pp.752-761


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