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Results

After collecting all relevant data, the ratios R1, R2, and R3 were calculated for each run. The results are given in Tables 12, and 3 respectively.


Table 1: Elastic monitor counts normalized to Faraday cup reading
Run E$_{in}$ Pressure FC4 (epA) Livetime Time (s) Elastics R1
7191 582.7 4.57 480 0.96 326 1421 702.2
7192 582.7 8.12 425 0.96 518 3726 740.6
7193 582.7 6.22 450 0.94 1160 6285 697.7
7194 582.7 6.21 430 0.92 748 4085 753.7
7202 471.9 5.82 387 0.90 696 4511 713.3
7210 784.2 7.42 350 0.95 2266 6696 740.1
7212 784.2 7.35 305 0.95 692 1758 734.6
7238 774.7 7.96 25 0.99 1150 203 540.4
7239 774.7 7.80 16 0.99 744 91 593.1
7240 774.7 7.80 17 1.00 394 21 242.2
7241 774.7 7.80 14 0.99 876 76 481.8
7242 774.7 7.86 13 0.99 1240 117 559.9
7243 774.7 7.73 15 0.99 1766 195 576.9
7244 774.7 7.77 13 0.99 2902 193 400.8



Table 2: Elastic monitor counts normalized to beta monitor
Run E$_{in}$ Pressure Charge Fraction Livetime Elastics $\beta$ Scaler R2
7191 582.7 4.57 0.34 0.96 61904 89.6M 18.3
7192 582.7 8.12 0.46 0.96 103794 91.8M 22.6
7193 582.7 6.22 0.40 0.94 39818 43.6M 21.0
7194 582.7 6.21 0.45 0.92 58324 68.5M 22.7
7202 471.9 5.82 0.41 0.90 71292 55.2M 22.8
7210 784.2 7.42 0.50 0.95 37058 65.5M 24.8
7212 784.2 7.35 0.47 0.95 16651 29.2M 23.7
7238 774.7 7.96 0.50 0.99 3391 4.92M 26.4
7239 774.7 7.80 0.51 0.99 981 1.42M 27.3
7240 774.7 7.80 0.37 1.00 194 3.57M 15.4
7241 774.7 7.80 0.45 0.99 3608 5.31M 23.6
7242 774.7 7.86 0.53 0.99 2946 4.39M 27.4
7243 774.7 7.73 0.42 0.99 1834 2.77M 21.6
7244 774.7 7.77 0.46 0.99 1201 1.74M 24.8



Table 3: Beta monitor counts normalized to Faraday cup reading
Run E$_{in}$ FC4 (epA) Charge Fraction Time (s) $\beta$ Scaler R3
7191* 582.7 480 0.34 326 2.06M 38.5
7192 582.7 425 0.46 518 3.09M 30.7
7193 582.7 450 0.40 1160 7.07M 34.1
7194 582.7 430 0.45 748 4.52M 31.3
7202 471.9 387 0.41 696 3.43M 30.8
7210 784.2 350 0.50 2266 12.0M 30.2
7212* 784.2 305 0.47 692 2.75M 27.7
7238* 774.7 25 0.50 1150 0.27M 18.5
7239* 774.7 16 0.51 744 0.12M 19.4
7240 774.7 17 0.37 394 0.08M 30.6
7241* 774.7 14 0.45 876 0.14M 25.3
7242* 774.7 13 0.53 1240 0.17M 19.8
7243* 774.7 15 0.42 1766 0.32M 29.1
7244* 774.7 13 0.46 2902 0.39M 22.7

* Data had unstable beta monitor readings.


One of the most striking results of this study is the drop in the value of R1 at 774.7 keV/u. Run 7240 has the most abnormally low value of R1, possibly due to a statistical fluctuation in the elastic counts (though this too is unclear). Even if we exclude this run, however, all other runs at the energy show a significant decrease in R1 compared to those at 784.keV/u. There is no evidence of a strong resonance at this energy, so it is unclear what could be causing this anomaly. The beam intensity is fairly low at this energy, though, so the FC4 readings may be approaching the level of noise, making the error quite large.

R3 also had a large uncertainty associated with it. This may be partially a result of unstable beta readings which occurred in eight out of the fourteen runs (our time window was defined by the time in which the elastic monitor counts, not the beta monitor counts, were constant). Of the runs with stable beta readings, one included the anomalous run 7240. Left with only five reliable results, there does not seem to be enough data to make any conclusions about the reliability of R3.

The most constant ratio proved to be R2. Its largest source of deviation appeared to be caused by a scatter in the charge state fraction F. If we assumed a constant F, however, the scatter decreased, and if we omitted the outlier run 7240, R2 showed only a 3.7% variation at 582.7 keV/u, and a 1.9% variation at 774.7 keV/u. A constant value for R2 indicates that while the beam may fluctuate, the counters are stable, and measure the same value to a few percent. As energy increases, however, there appears to be a slight increase in R2, making it uncertain whether this value will be useful as a ``universal constant.''


next up previous
Next: Recommendations Up: BeamNormalization Previous: Data Analysis
Catherine Neish 2003-03-12