Dear all, I’m very new to using OPAL, so I’d appreciate a bit of guidance. In order to model an RFQ, I want to import a field map. How do I add this field map into the input file? On the wiki, I can only find how to apply field maps as edge fields on a magnet. I want the field map to fill the space where I currently have a drift in the attached input file. I’m sure I’ve made many other mistakes in the input file. Please do correct me—I’m eager to learn! Many thanks for any help. Matt From: srs0=ip/g=lf=lists.psi.ch=opal-owner AT srszone.org <srs0=ip/g=lf=lists.psi.ch=opal-owner AT srszone.org> On Behalf Of Adelmann Andreas (PSI)
Sent: Wednesday, August 22, 2018 11:42 PM
To: Daniel Winklehner <winklehn AT mit.edu>; Matt Easton 董昊 <matt.easton AT pku.edu.cn>
Cc: Opal AT lists.psi.ch
Subject: Re: [Opal] OPAL code for simulating RFQs Dear all, let me clarify a few things: To be honest, I haven’t pursued using OPAL for RFQ’s much after our last email exchange. To answer some of your questions: I don’t think OPAL is related to Impact, but maybe it uses similar style input? Andreas can definitely comment on that.
OPAL is an electrostatic PIC and that is the only relation to Impact.
You can definitely load a 3D electrostatic field in OPAL-T and give it a sinusoidal variation at your desired frequency. What is missing, in my opinion, to make it suitable for RFQ’s are the correct periodic boundary conditions in the longitudinal direction (they had been implemented previously, but don’t seem to be working at the moment).
For testing purposes, you could inject a beam that has length 2-3 times of an RF period. And select only the particles from the middle during analysis. This is a bit of a crude workaround. Another question is particle termination on the RFQ vanes. I think all the code is there to even load a meshed (vtk) version of the actual vanes and use those for termination, but I don’t know if it is implemented for use in the T tracker (I used it for the central region of our cyclotron in the OPAL-cycl flavor).
Yes the code is there however OPAL-t can not access the routines for the moment.
For our project, I have been working with a student to create a python module that works seamlessly with another code, called WARP, and we have seen some success there. It is close to the point where I would feel comfortable if other people wanted to use it. I can definitely let you know how that endeavor progresses. That being said, I would still like to see OPAL being able to handle RFQ’s as well. Benchmarking of the two codes against each other and against known codes like TOUTATIS would be really helpful.
I agree it would be very helpful, however someone needs to take up the task and - fix the boundary conditions - add the geometry to OPAL-t
Hope this helps a little bit, What is the latest status of simulating an RFQ using OPAL? I know it was a long time ago that I first asked about this, but with one thing and another it would be useful for me now to be able to import a field map for an RFQ. In my fiddling around with OPAL and trying to learn from the Wiki, I think it said that OPAL-t is related in some way to Impact-T. Is that right? Right now I can model my RFQ in Impact-T by importing a 3D electrostatic field map and applying a sinusoidal variation at the RF frequency. I’d love to be able to do the same thing in OPAL. I’ve set up a crude simulation with a single drift and a square aperture for the length of the RFQ, so all that is missing is the field. Fromhttps://gitlab.psi.ch/OPAL/Manual-2.0/wikis/fieldmaps it seems that such 3D dynamic field maps are supported, but I think these are applied only as edge fields for a magnet. How can I use a field map by itself, or apply it to a drift space? Thanks for your help. If it would be better to send this on the OPAL support mailing list, I’m happy to do that too. Post-Doctoral Researcher 博士后研究员 Institute of Heavy Ion Physics 重离子研究所 Apologies for taking so long to respond. Unfortunately, currently, I would not recommend using OPAL for RFQ’s. I have done some preliminary studies with some success, but there are a few issues that need to be solved in order for it to become widely usable. As Andreas said, the idea is to import a field map from a BEM or FEM program and track the particles in OPAL. This requires correct particle termination and periodic boundary conditions, both of which are currently a work in progress. These issues are being addressed, or will be in the near future, though and I will be happy to let you know about the new results when the time comes. Thanks for your response, and thanks to Suzie for putting us in touch. I’d be very interested to hear the status of the RFQ modelling effort, thanks for connecting me with Daniel. Post-Doctoral Researcher 博士后研究员 Institute of Heavy Ion Physics 重离子研究所 Daniel (in cc) can update you on our RFQ modelling effort w.r.t the IsoDAR RFQ injection project. If I remember correctly, we aim to import field maps from RFQ-Design programs and the track in OPAL. In case you consider adding a specific RFQ Element in OPAL please do so, OPAL is open source easy to extend. ------
Dr. sc. math. Andreas (Andy) Adelmann
Staff Scientist
Paul Scherrer Institut WBBA/219 CH-5232 Villigen PSI
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============================================ Best to chat to Andreas Adelmann about those aspects, CC’d in. I should be at IPAC this year as I’m planning to go down to Fermilab after for the IOTA meeting. Hope we can grab a drink there? How are you doing? It’s been a while since we’ve been in touch. Are you going to be at IPAC this year? I’ve been working on adding some particle–particle / particle–matter interactions (currently in quite a basic form) to the tracking code Impact-T, to which we’ve already added RFQ and DTL tracking modules. But then I saw a recent paper about OPAL, that it already has proper Monte Carlo simulations incorporated into it. And then I saw your name on the list of people that developed it! Would you be able to tell me a bit more about OPAL, or point me in the direction of the right person to talk to? I’m interested in tracking high intensity beams through an RFQ, and processes such as stripping electrons from ions and dissociation of compound ions into smaller particles, etc. Post-Doctoral Researcher 博士后研究员 Institute of Heavy Ion Physics 重离子研究所
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