RF cavity transient analysis with TraceWin

[Bruce Yee]

Dear Didier,

On the manual, the quality factor of the loaded cavity (QL) is given by:

1/QL=1/Q0 + 1/Qi + 1/Qt... (1)

How TraceWin estimated the incident coupling (Qi)?

Qt is given, and Q0 can be estimated from the input parameters. I would like it if you could explain to me a little more about Qi.

Best regards,

Bruce

[Didier]

Dear Bruce,

Qi is calculated one time at begening as following:

Qolow=G/Rs*(1+A*Eaccnom);
Q0i=Qolow-(3./4.)*Qolow*Eaccnom/10e6;
Qi=Eaccnom*Lacc/(rsq*I_Beam*cos(Ph_Sync)+Eaccnom*Lacc/Q0i);

Regards,

Didier

[Bruce Yee]

Dear Didier,

Thank you very much for the information.

I have to more questions:

1) About the equation "Q0i=Qolow-(3./4.)*Qolow*Eaccnom/10e6;", Could you tell me how this equation is obtained? or some references.

2) When you said that "Qi is calculated one time in the beginning"?
Do you mean that later it is estimated by other relation like Qi= omega*U/Pinc?

Thanks again for your time and help.

Bruce

[Didier]

Dear Bruce,

For the moment I can't seriously answer your questions without asking the historical developer of this part of the code. Coming back only at the end of August, I will try to clarify these points at that time

Regards,

Didier

[Didier]

Hi,

Finally, I was able to exchange with the expert on these questions here and I can better answer your questions.

1) This equation is only a linear estimation of the behaviour of Qo as a function of Eacc starting from a more or less usual curve. In any case Qo has little impact on QL

2) Qi is not re-evaluated in the transients, we consider this sufficient.

Regards,

Didier