Search found 40 matches

by GPenn
03 Nov 2020, 18:16
Forum: Bugs
Topic: Minor bug with frequency_map, but causes segmentation fault
Replies: 1
Views: 7845

Minor bug with frequency_map, but causes segmentation fault

Hi, I have noticed an issue where if I run frequency_map on a lattice that starts with a CHARGE element, it quickly generates a segmentation fault (message is: Terminated by SIGSEGV). Attached is a simple example based on the example given in PAR/frequencyMap It's very easy to just not have the CHAR...
by GPenn
18 May 2020, 16:39
Forum: Feature Requests
Topic: Uniform corrector fields in CSBEND element?
Replies: 2
Views: 8377

Re: Uniform corrector fields in CSBEND element?

Michael,

Having the steering available in CSBEND would help me a lot.

I was wrong about there being a problem combining Fn and Kn, I must have changed multiple things at once and blamed it on that particular aspect of the lattice when it didn't do what I expected.

Thanks,
Gregg
by GPenn
18 May 2020, 16:35
Forum: Ring Tracking
Topic: Issue with moments_output for a very perturbed ring
Replies: 4
Views: 1748

Re: Issue with moments_output for a very perturbed ring

Thank you Michael, Separating the kicks out is straightforward, I will see what it does. To be clear, there is no bug with KQUAD elements, just KSEXT? The errors on the magnets in that lattice file are a little strange, I think there is supposed to be a combination of local and global corrections go...
by GPenn
17 Apr 2020, 17:30
Forum: Feature Requests
Topic: Uniform corrector fields in CSBEND element?
Replies: 2
Views: 8377

Uniform corrector fields in CSBEND element?

It would be convenient to include additional uniform dipole fields in bending elements such as CSBEND, to be used as correctors instead of affecting the nominal orbit. This is especially true for offset quadrupoles that are being labelled as CSBEND magnets (even though the CCBEND element would be a ...
by GPenn
30 Mar 2020, 20:25
Forum: Ring Tracking
Topic: Issue with moments_output for a very perturbed ring
Replies: 4
Views: 1748

Issue with moments_output for a very perturbed ring

Hi, I have been looking at the ALS-U ring with large errors that have been corrected with kicker magnets and other adjustments. The final beamline was converted from AT simulations. Although it looks like there is a closed orbit, moments_output produces the following error message: Warning: particle...
by GPenn
21 Feb 2020, 17:16
Forum: Ring Tracking
Topic: Question about having a fiducial bunch in a ring with bunches from sdds file
Replies: 3
Views: 5241

Re: Question about having a fiducial bunch in a ring with bunches from sdds file

Thank you, that helps a lot! I was definitely veering in the wrong direction.

-Gregg
by GPenn
06 Feb 2020, 13:23
Forum: Ring Tracking
Topic: Question about having a fiducial bunch in a ring with bunches from sdds file
Replies: 3
Views: 5241

Question about having a fiducial bunch in a ring with bunches from sdds file

Hi, I am doing ring simulations for long range wakes and ion effects. I would like to include a first fiducial bunch while using n_passes_fiducial=1 in the run_control command. The bunches are from an SDDS file, so I am using the sdds_beam command. This works fine if I follow the example from the fo...
by GPenn
28 Jan 2020, 19:50
Forum: Bugs
Topic: synch_rad losses in quad with nonzero kick
Replies: 1
Views: 4679

synch_rad losses in quad with nonzero kick

In a KQUAD element with |K1|>1, if either HKICK or VKICK is nonzero (it doesn't matter how small) then the radiation losses are oversized and scale quadratically with K1. An electron could lose more than an MeV in a modest-strength magnet. KSEXT elements have the same issue with the value of K2. In ...
by GPenn
09 Jan 2020, 18:57
Forum: Bugs
Topic: Tracking issues in CSBEND elements in the presence of errors
Replies: 9
Views: 10512

Re: Tracking issues in CSBEND elements in the presence of errors

Thanks Mike, That clarifies things a lot. I think the problem is simply that I'm comparing elegant to a model that is too simplistic. It's harder than I thought to account for the difference between the physical centerline of the magnet and the reference orbit when there is an error in the tilt. I'm...
by GPenn
07 Jan 2020, 19:27
Forum: Bugs
Topic: Tracking issues in CSBEND elements in the presence of errors
Replies: 9
Views: 10512

Re: Tracking issues in CSBEND elements in the presence of errors

The revised code works great. Now putting ETILT and TILT with the same sign gives completely consistent behavior including for off-momentum particles. I have one final question just to make sure I'm interpreting things correctly. It looks like in the CSBEND element, FSE and ETILT do not impact quadr...