In RFX a monitor for the measurement of the on-axis electron temperature with high temporal resolution has been designed and operated during the last experimental campaigns. It consists of four soft x-ray (SXR) diodes which observe the plasma through four beryllium filters of different thickness. In this article the main design issues are presented. The measured values of the temperature, computed both with the standard double foil method and with a fit of all the available signals, are reported, correlated with the main plasma parameters and briefly compared with the results of other diagnostics. The main causes of systematic error, the effect of the noise and the reliability of the results in various plasma conditions have been investigated. Dynamic evaluations of the temperature up to a maximum bandwidth of 5 kHz are described, confirming the potentialities of the technique to follow fast phenomena. Possible improvements of the diagnostic and future developments are also pointed out.

1.
S. Ortolani and D. D. Schnack, Magnetohydrodynamics of Plasma Relaxation (World Scientific, Singapore, 1993).
2.
P.
Martin
,
A.
Murari
, and
L.
Marrelli
,
Plasma Phys. Controlled Fusion
38
,
1023
(
1996
).
3.
L.
Fellin
,
P.
Kusstatscher
, and
G.
Rostagni
,
Fusion Eng. Des.
25
,
315
(
1995
).
4.
M.
Bassan
,
R.
Pasqualotto
,
A.
Sardella
, and
L.
Giudicotti
,
Rev. Sci. Instrum.
61
,
2846
(
1990
).
5.
L.
Carraro
and
M.
Valisa
,
Rev. Sci. Instrum.
61
,
2801
(
1990
).
6.
T. P.
Donaldson
,
Plasma Phys.
20
,
1279
(
1978
).
7.
J.
Kiraly
et al.,
Nucl. Fusion
27
,
397
(
1987
).
8.
L.
Marrelli
,
P.
Martin
, and
A.
Murari
,
Meas. Sci. Technol.
6
,
1690
(
1995
).
9.
L.
Carraro
et al.,
Nucl. Fusion
36
,
1623
(
1996
).
10.
P.
Martin
et al.,
Rev. Sci. Instrum.
68
,
1256
(
1997
).
11.
R. T.
Snider
,
Rev. Sci. Instrum.
66
,
546
(
1995
).
12.
W. R. Wing, Proceedings of the Course on Plasma Diagnostics and Data Acquisition Systems, Varenna, Italy, 1975.
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