The upgraded spectrometer used for charge exchange recombination spectroscopy on the Madison Symmetric Torus resolves emission fluctuations up to 400 kHz. The transimpedance amplifier’s cutoff frequency was increased based upon simulations comparing the change in the measured photon counts for time-dynamic signals. We modeled each signal-processing stage of the diagnostic and scanned the filtering frequency to quantify the uncertainty in the photon counting rate. This modeling showed that uncertainties can be calculated based on assuming each amplification stage is a Poisson process and by calibrating the photon counting rate with a DC light source to address additional variation.
REFERENCES
1.
D.
Craig
, D. J.
Den Hartog
, D. A.
Ennis
, S.
Gangadhara
, and D.
Holly
, Rev. Sci. Instrum.
78
, 013103
(2007
).2.
D.
Carmody
, M. J.
Pueschel
, and P. W.
Terry
, Phys. Plasmas
20
, 052110-1
(2013
).3.
D.
Carmody
, M. J.
Pueschel
, J. K.
Anderson
, and P. W.
Terry
, Phys. Plasmas
22
, 012504-1
(2015
).4.
L.
Lin
, J. K.
Anderson
, D. L.
Brower
, W.
Capecchi
, W. X.
Ding
, S.
Eilerman
, C. B.
Forest
, J. J.
Koliner
, D.
Liu
, M. D.
Nornberg
, J.
Reusch
, and J. S.
Sarff
, Phys. Plasmas
21
, 056104
(2014
).5.
Photomultiplier Tubes Basics and Applications, 3rd ed. (Edition 3a), Hamamatsu Photonics, (2007), p. 127.
6.
LTspice IV, http://www.linear.com/designtools/software/.
7.
Z.
Liu
, W.
Hunt
, M.
Vaughan
, C.
Hostetler
, M.
McGill
, K.
Powell
, D.
Winker
, and Y.
Hu
, “Estimating random errors due to shot noise in backscatter lidar observations
,” Appl. Opt.
45
, 4437
-4447
(2006
).8.
ET Enterprises Electron Tubes, 9125B Series Data Sheet, https://my.et-enterprises.com/pdf/9125B.pdf.
© 2016 Author(s).
2016
Author(s)
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