measuring current in accelerator

david allen

Hi
I could not figure out what is the reason of measuring current in accelerator and it shows which features of the beam?
any help would be appreciated.

Astronuc

Currently is readily measurable. Current has units of charge per unit time, to the current is related to the rate at which charge passes a given point or cross-section of the beam. The charge is just the product of the number of particles and their charge, so measuring the current can give one a measurement of the particles passing a given cross-section of the beam at any moment. Assuming the losses are neglible, the current leaving the source = current arriving at target.

silverback011

From the experiments I have participated in, we used current only to determine how much of the particular charged isotope was going down the beam pipe and to aid in “steering” the beam onto a stationary target.

Just a quick overview, we would insert “cups” into the beam which were essentially metal plates that measured current to determine if the beam was still going down the middle of the pipe as we desired and to see how much of the beam was present at that point. Magnets installed along the beam pipe were used either to focus or deflect the charged ions along the path we desired. We would adjust the magnets as needed to obtain the maximum amount of the beam as possible. Once that was accomplished, we withdrew the “cup” and put in the next one further down the beam pipe and repeated the process until the beam made it to the stationary target. At the lab I worked at we used a quartz (it would give off light) with a camera so we could see if the beam was hitting the target frame. Once the beam was “tuned” we installed the target and looked at the data to ensure we were producing what we wanted to study.

david allen

the answer shows the track too me. Hence I've got a question in implanters, the equation between impurities, time on the wafer because if beams radiate impurities on that area is too high.