C9 Interferometer

Instructions for use

Step 1: Set the valves as shown in Figure A. Then turn on the vacuum pump and the laser. Allow the vacuum to completely pump down the test chamber. Connect the green hose to one of the three test ports on C9.

Step 2: While watching the projection of the laser beam, set the valves as shown in Figure B. Begin the flow of the Cerenkov gas into the test chamber while counting the fringes in the projected laser beam.

Calibration table

Let n = the index of refraction
Let f = the number of fringes
Then (n-1) is given by:
n-1 = f / (51195 +/- 1%)
(See page 90 of the C9/H9 logbook for more information).

FringesIndex ofbeta*gammaPionKaon
refractionat threshmomentummomentum
+/- 15%for C lightthreshthresh
(GeV/c)(GeV/c)
50 1.00098 22.6 3.16 11.17
51 1.00100 22.4 3.13 11.06
52 1.00102 22.2 3.10 10.95
53 1.00104 22.0 3.07 10.85
54 1.00105 21.8 3.04 10.75
55 1.00107 21.6 3.01 10.65
56 1.00109 21.4 2.98 10.55
57 1.00111 21.2 2.96 10.46
58 1.00113 21.0 2.93 10.37
59 1.00115 20.8 2.91 10.28
60 1.00117 20.6 2.88 10.19
61 1.00119 20.5 2.86 10.11
62 1.00121 20.3 2.84 10.03
63 1.00123 20.2 2.81 9.95
64 1.00125 20.0 2.79 9.87
65 1.00127 19.8 2.77 9.79
66 1.00129 19.7 2.75 9.72
67 1.00131 19.5 2.73 9.65
68 1.00133 19.4 2.71 9.58
69 1.00135 19.3 2.69 9.51
70 1.00137 19.1 2.67 9.44
71 1.00139 19.0 2.65 9.37
72 1.00141 18.8 2.63 9.31
73 1.00143 18.7 2.61 9.24
74 1.00145 18.6 2.59 9.18
75 1.00146 18.5 2.58 9.12
76 1.00148 18.3 2.56 9.06
77 1.00150 18.2 2.54 9.00
78 1.00152 18.1 2.53 8.94
1.001532.528.91
79 1.00154 18.0 2.51 8.88
80 1.00156 17.9 2.50 8.83
81 1.00158 17.8 2.48 8.77
82 1.00160 17.7 2.46 8.72
83 1.00162 17.6 2.45 8.67
84 1.00164 17.4 2.44 8.61
85 1.00166 17.3 2.42 8.56