General Tuning

For the most part, all devices may be tuned to maximize the beam transmission. There are only a handful of devices that we don't tune: dee phases and trim coils (besides bumps). There are however devices that are more common to tune.

For a normal, quick tuneup of the k500, tune the following while sending beam to FC2007:

• Dee voltages K5DVR_A/B/C
• Centering bump magnitude and phase K5CM and K5CP
• Extraction bump magnitude and phase K5XM and K5XP
• Inflector voltage K5SICA-V and K5SIAN-V
• Injection steering J050DH and J051DE
• Main field epsilon

It is often useful to go through these devices multiple times since the effects of many devices are interrelated.

It is best the tune the injection line devices on accelerated beam, either on FC2007 or on the main probe inside the machine. In this configuration, you may be sure that the beam you are measuring is the correct one and not an analog. You will also be optimizing the beam for injection/extraction into the K500, rather than just beam transport to the end of the injection line. At this point, all devices may be tuned. Suggest to start with correctors, then focusing elements. Iteration is necessary. If time permits, it may help to quad center. This must be done using viewers. It is important to send beam into the k500 to see if the changes actually helped injection efficiency.

There is an added complication when running cocktail beams. Each beam species overlaps in the injection line, and some may be at higher intensities than the other. This means that tuning on a faraday cup in the injection line may bias the tune towards one or the other species which might not be desirable. It is best to spend time tuning the injection line on accelerated pilot beam (ie the beam at the center of the range of epsilons in the cocktail)

Tuning the k500 extraction is best done during initial beam setup. It is not a short term tuning activity, and is not the first thing to try when restoring a saveset. During this process extraction drive positions for the deflectors E1 and E2, mag channels M1-M8, and compensating bars C1 and C2, as well as deflector voltages should all be adjusted. These devices should be changed in conjunction with adjustments to the main field and the bumps/dees. The primary goal is to improve transmission into the extraction channel and from there to the faraday cup FC2007. While doing this, minimize the beam current lost on the main probe scraper jfjfjfjf and the m-channels MGCH-ALL. Some pitfalls to be aware of:

• Some m-channels may be intentionally out of the beam path. M3, M4N and M4W, and M7N and M7W may be out. Check the beam calculations and/or look at their positions compared to drives up/downstream.
• Moving the m-channels can move the beam position at D2007. It is necessary to check the viewer to see if the beam is centered. If the beam is near the edge of the faraday cup, it will read high but this is artificially inflated.
• The beamspot shape may change. This could affect transmission to SEE.

HEBT Tuning