surface temperature/℃	rotational temperature/K(cavity size 100um)	rotational temperature/K(cavity size 150um)
30	707.9	886.8
40	730	904.3
70	763.6	920.6
90	787.4	
110	806.6	
135	818.8	991.2
155	850.8	998.2
175	849.5	1006.6
200	889.9	1031.1
215	893.8	1037.7
240	902.7	
260	911.9	


The variation of $T_{\rm rot}$ with $T_{\rm surf}$ for two different sized discharge cavities (100 $\mu$m and 150 $\mu$m). $T_{\rm rot}$ errors are within 15 K.  Conditions: 2 slm He, and an operating voltage amplitude of 500 V.