Mike V, Richard S, Shivaraj K and Darkhan T

Pcal efficiency measurements were taken at EndX on 07/22/2014, 07/23/2014 and 07/24/2014.

We took in-chamber and out-of-chamber measurements on 07/22/2014 and saw >2% power drop between transmitter output and receiver input (overall efficiency). On the same day during several measurements in the beginning halogen chamber illumination lights were turned on. During measurements on following days we kept halogen illumination off.

Since major power drop was between transmitter output and ETMX input (viewport+periscope), on 07/23/2014 before taking any measurements we wiped some of the periscope mirrors.

By now we have
* 3 samples of in-chamber measurements, efficiency of ETMX at Pcal laser wavelength (1047nm) and two viewports separately;
* 5 samples of out-of-chamber measurements, for overall efficiency calculations.


	

		

			
Date, sample #
			
07/22/2014
			
07/23/2014
sample 1
			
07/23/2014
sample 2
			
07/24/2014
sample 1
			
07/24/2014
sample 2
		
		

			
Efficiency of the viewport at transmitter module
		
		

			
inner beam
			
0.9870
			
0.9936
			
0.9943
		
		

			
outer beam
			
0.9756
			
0.9916
			
0.9892
		
		

			
Efficiency of ETMX (reflectivity)
		
		

			
inner beam
			
0.9975
			
1.0003
			
0.9986
		
		

			
outer beam
			
0.9938
			
0.9978
			
0.9993
		
		

			
Efficiency of the viewport at receiver module
		
		

			
inner beam
			
0.9935
			
0.9951
			
0.9960
		
		

			
outer beam
			
1.0021
			
1.0008
			
1.0011
		
		

			
Overall efficiency
		
		

			
inner beam
			
0.9781
			
0.9890
			
0.9890
			
0.9858
			
0.9876
		
		

			
outer beam
			
0.9717
			
0.9902
			
0.9897
			
0.9836
			
0.9848
		
	


Background readings
* for WS were ~0.03mV (< 0.01% from laser beam unshuttered reading);
* for TXmon were ~4.45mV (< 0.5% from laser beam unshuttered reading).

Variation of ratios WS/TXmon of up to +/-0.5% were observed in most of the measurements, we assume that it's mostly due to temporal laser speckle variations.

RXmon/TXmon calibrations:
* on 07/23/2014 - 2.3539;
* on 07/24/2014 - 2.3445.