synchrotron tune

[simone.dimitri]

Hello everybody. Few basic questions about the inclusion of RF in a ring:

1) I am including "RFCA" elements in my lattice file (.lte), and I also turned on synchrotron radiation (and ISR=0). Is this enough to take into account synchrotron oscillations during particle tracking? Or, shall I use the "rf_setup" command in the .ele file instead?

2) Let us suppose the RF is now set properly. Is there any simple way to evaluate the synchrotron tune? I would like to scan the synchrotron tune vs., e.g., RF frequency, but I could not find examples to do that.

Many thanks in advance,
Simone

[michael_borland]

Simone,

1) I am including "RFCA" elements in my lattice file (.lte), and I also turned on synchrotron radiation (and ISR=0). Is this enough to take into account synchrotron oscillations during particle tracking? Or, shall I use the "rf_setup" command in the .ele file instead?

You'll either need to set up the RFCA elements by hand (set the phase, frequency, and voltage), or use &rf_setup. I recommend using &rf_setup, since that handles precisely setting the rf frequency and phase.

2) Let us suppose the RF is now set properly. Is there any simple way to evaluate the synchrotron tune? I would like to scan the synchrotron tune vs., e.g., RF frequency, but I could not find examples to do that.

You can perform multi-turn tracking of a single particle and record the turn-by-turn information with a WATCH element with mode="centroids". You'll need to kick the beam in momentum on the second turn in order to seed the oscillation, using a MALIGN element

Code: Select all

mal1: malign,dp=1e-4,on_pass=1

Turning off quantum excitation is best in this case, since it only confuses matters. However, an easier and faster way is to use the script longitCalcs. It allows varying the voltage and tells you the rf parameters, including the synchrotron tune.

--Michael

[michael_borland]

Simone,

Here's a tracking example.

--Michael