In my notes I have several references to using Allen-Bradleys to
measure temperature:
J.R. Clement and E.H. Quinnel, Rev. Sci. Instrum. 23:213 (1952)
F.J. Kopp and T. Ashworth, Rev. Sci. Instrum. 43:327 (1972)
W.N. Lawless, S.K. Hampton, and C.F. Clark, Rev. Sci. Instrum. 59:2505 (1988)
Omega Inc. temperature product catalog
The two most commonly used fits have 3 parameters:
(1) log(R) + k/log(R) = A + B/T
(2) log(R) = C + D/T^p
I believe these equations are empirical. Eq. (2) is the same form as
John Denker obtained by fiddling. However, for day-to-day lab work we
have found that a reasonable approximation is the 2-parameter fit:
(3) T = E*ln(R)/[ln(R)-F]^2
One should replace R by R - R_lead if the lead resistance is
significant. A 2-parameter fit is easier to use because in practice
you can simply drop the resistor into liquid helium and liquid
nitrogen at atmospheric pressure (corrected for the altitude of your
lab). The fit works well at lowest temperatures of course, but can
with some error be pushed as high as 100 K.
--
Dr. Carl E. Mungan, Assistant Professor http://uwf.edu/cmungan/
Dept. of Physics, University of West Florida, Pensacola, FL 32514-5751
office: 850-474-2645 (secretary -2267, FAX -3323) email: cmungan@uwf.edu