Results from photon yield analyses

As a result of the differing Cherenkov ring radii from different radiators and experimental configurations, the number of HPDs which are used to determine the photon yield for each type varies. The layouts are specified in Table 2.

Table 2: Summary of the different detector, optical and radiator configurations used to study the photon yield.

Layout	Radiator	Filter	Config.	No. of
				HPDs
1	Air	None	1	1
2	C4F10	None	1	1
3	C4F10	None	2	4
4	C4F10	Mylar	2	2
5	Aerogel 1	None	1	4
6	Aerogel 1	Glass	1	4
7	Aerogel 1	Mylar	1	6
8	Aerogel 2	Glass	1	4

The results from Analysis 1 for each of the above layouts are shown in Table 3 where they are also compared with results from simulation under the same conditions.

Table 3: The observed, background & efficiency corrected, and expected number of detected photoelectrons for the various radiator and filter configurations determined using Analysis 1.

Layout	Raw	Backgnd.	Efficncy.	${\frac{\mathrm Observed}{\mathrm Predicted}}$
		Corr.	Corr.
1	4.92	4.56	4.80	0.90
2	7.85	7.49	34.80	1.02
3	12.83	12.77	89.46	1.05
4	1.78	1.76	24.66	1.46
5	1.79	1.31	11.39	0.73
6	1.14	0.75	6.52	0.92
7	1.34	0.81	3.71	0.64
8	0.85	0.52	4.52	1.10

Similarly, results from Analysis 2 are summarised in Table 4.

Table 4: Observed and expected numbers of detected photoelectrons for the various radiator and filter configurations determined using Analysis 2. The final column indicates the mean of the two analyses for the ratio of Observed/Predicted numbers of photoelectrons.

Layout	Observed	Observed	Mean ${\frac{\mathit Observed}{\mathit Predicted}}$
		Predicted	(Anal. 1 & 2)
1	5.06	0.88	0.89
2	7.15	1.01	1.02
3	12.42	1.10	1.08
4	1.85	1.39	1.42
5	1.80	0.67	0.70
6	1.18	0.95	0.94
7	1.45	0.90	0.77
8	0.83	1.15	1.12

Due to differences in the numbers of pixels used and in the pedestal selection between the two analyses, it is not possible to compare directly the raw numbers of observed photons for each layout. Instead, the combined ratio of number of photons observed to that predicted is averaged for the two methods and are given in the final column of Table 4.