Pyrometer
=============

An infrared pyrometer (Cyclops 160B, 1.6\ mu\ m, 200..1400\ deg\ C) , with tripod, is available for contactless temperature measurements through the chamber windows. 

.. image:: /_static/pyrometer/cyclops_pyrometer.jpg
  :width: 400
  :align: center


For this operating wavelength no special window materials are required, it can see through quartz. However **you should not assume that all windows are clean** - if a window has been coated by past evaporations, you will under-read the temperature.

Temperature measurement with a pyrometer should be considered reproducible, but poorly calibrated. Proceed with caution.

**Emissivities at 1.6\ mu\ m**

==========  ==================  =======================
Material    Emissivity, clean   Emissivity, oxidised
==========  ==================  =======================
Ag 			0.04 				0.10
Al 			0.09 				0.40
Au  		0.02
Be  		0.3
Cr  		0.34 				0.80
Co  		0.28 				0.65
Cu  		0.05 				0.85
Fe  		0.30 				0.85
Graphite   	0.85
Mg  		0.24 				0.75
Mo  		0.25 				0.75
Ni   		0.25 				0.85
Pb 			0.28 				0.65
Pd 			0.23
Pt 			0.22
Si  		0.67
Sn 			0.28 				0.60
Ti 			0.50 				0.80
W   		0.30
==========  ==================  =======================


Silicon emissivity from :download:`this paper <_static/pyrometer/sato.pdf>`

Be emissivity is just the value we've always used in the past; I can't back up that number.

All other values are taken from the Cyclops L user guide


.. mu    unicode:: U+03BC
.. deg    unicode:: U+00B0