Strip Beam Position Monitor
As the name suggests, a Beam Position Monitor (BPM) is a device to detect and record the location of the beam bunches moving through a particular segment of the accelerator.
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The BPM consists of four metal
strips on the inside of the accelerator structure,
connected to wires that extend outside the structure
and are grounded. The entire apparatus is electrically
isolated from the accelerator structure itself.
There are over 250 beam position monitors in the linac. |
| The information from the four strips can be used to measure the number of electrons in the bunch and determine the position of the bunch as it passes between the strips. There can be as many as 40 billion electrons in a bunch. |
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