Elegant users forum

Mike,

I have a lattice that I am trying to ramp the energy in. I am also attempting to ramp the RF voltage and phase compensate for synchrotron radiation losses in the ramp. I'm using RAMPP and RAMPRF for this. I think I've put together the correct SDDS files for this. However, even after 3 turns (where the is essentially no ramping), I loose all of my particles. I've attached my files and was hoping that you could take a look. I've also included the excel spreadsheet that I made CSV files with and then converted to SDDS with csv2sdds.

Thanks

Ray

Ray,

The main problem I see with your files is that you're syntax is wrong for giving the ramp information. You need to use the form VOLT_WAVEFORM="<filename>=<timeName>+<ratioName>". You are not giving the column names, and your files have absolute values rather ratios or offsets as required. See the manual page for RAMPRF at http://www.aps.anl.gov/Accelerator_Syst ... de142.html
There are similar issues for RAMPP.

Also, I suggest using first order tracking with SBEN's and SREFFECTS rather than CSBEN and elment-by-element radiation. Otherwise it is too slow. If you need more detailed dynamics, you can use ILMATRIX.

I'll try to cook up an example and post it later.

--Michael

Ray,

Using your files, I made a nicely-packaged example that can be run with minimum effort. I compute the rf waveforms from scratch based on the momentum ramp and scaling of the energy loss etc.

See the attached tar file. As usual, it probably won't work without modification on Windows.

--Michael

Mike,

Thanks for the assistance. I'll give it a shot. I see most of my errors with one exception. What did I not do right when I made the original magnet ramp sdds file? What it just not specifying the filename syntax right in the .lte file? Or did I do the csv2sdds conversion wrong?

Judging by the contents of the file, I'll become an ELEGANT example.

Ray

Nevermind. I got my original files to work. Thanks Michael.

Ray,

Glad to hear you got it working. By the way, here's a movie I made of a ramp from 200 MeV to 3 GeV


--Michael

Michael,

Fancy! I like it. What is nice is that the emittance curve looks pretty much like we predicted. I'ts great stuff when life works out like that!
Thanks for all of the help.

Ray

Thanks Michael.

Hi Michael,

You mentioned once in one of the previous posts:

"... Also, I suggest using first order tracking with SBEN's and SREFFECTS rather than CSBEN and elment-by-element radiation. Otherwise it is too slow. If you need more detailed dynamics, you can use ILMATRIX."

This remind me that it may related to the problem I'm facing now. Wish to get help from you!

I've been trying to simulate the TMCI in a booster considering the energy ramping process. I use ILMATRIX to represent the one-turn map, and the SREFFECTS to represent the synchrotron radiation effects. However, the problem is that there is no magnets in the lattice file, so that the SREFFECTS element cannot update the parameters during the ramping process automatically (Is may understanding correct?). I haven't figured out a way to solve this problem. I checked the example "boosterRamp". In the example, the lattice is represented element-by-element. I wonder whether the ILMATRIX element can be used in this kind of simulation. Wish to get help from you!

Thanks a lot in advance!

Haisheng

michael_borland wrote:Ray,

The main problem I see with your files is that you're syntax is wrong for giving the ramp information. You need to use the form VOLT_WAVEFORM="<filename>=<timeName>+<ratioName>". You are not giving the column names, and your files have absolute values rather ratios or offsets as required. See the manual page for RAMPRF at http://www.aps.anl.gov/Accelerator_Syst ... de142.html
There are similar issues for RAMPP.

Also, I suggest using first order tracking with SBEN's and SREFFECTS rather than CSBEN and elment-by-element radiation. Otherwise it is too slow. If you need more detailed dynamics, you can use ILMATRIX.

I'll try to cook up an example and post it later.

--Michael

Haisheng,

Here's an example using ILMATRIX.

--Michael