Cross section through the model of the beam profile monitor. The proton beam is coming from the right.
(a) Photograph of the aluminum Faraday cup. The discoloration is caused by the proton beam. (b) View from the back into the monitor with the Faraday cup removed. The lattice structure of the two electrode planes is clearly visible.
Overview of the electronics assembly. BPM – beam profile monitor, SB – switch box, HV – high voltage, ch. – channel, I-V – current to voltage amplifier, Amp. – amplifier, ADC – analog to digital converter, and PC – personal computer. See text for more detail.
Examples of a typical tune without special tuning (a) and an optimized tune (b). The numbers in the gray scale are in μA.
Graph showing the proton beam being steered into the far corners of the beam profile monitor: (a) top left, (b) top right, (c) bottom left, and (d) bottom right. The numbers in the gray scale are in μA.
(a) A radiograph of a typical proton beam profile, HAVAR foil irradiated for 5 min, film exposed to the foil for 30 min. (b) X cross section of the radiograph and (c) Y cross section.
Profile of a proton beam at the start of a run (a) and after 30 min (b). The numbers in the gray scale are in μA.
The graphs show the dependence of the Faraday cup current on the sum of the electrode currents in the X and the Y planes. The data in the top row, (a) and (b), were taken with all electrodes biased. The adjusted R-Square value of the linear fit for the X plane is 0.99738 and for the Y plane is 0.9938. The bottom row, (c) and (d), shows the result of two measurements in one plane with all odd number channels grounded and even channels biased and the reverse, again for both planes. The adjusted R-Square value of the linear fit is 0.99937 for the X plane and 0.99939 for the Y plane.
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