The OPAL Discussion Forum

[Andreas Adelmann <andreas.adelmann AT psi.ch>]

Hello Norman well you from the following collaboration diagram (http://amas.web.psi.ch/docs/opal/html/classRFCavityRep.html)

you can see that if you inherit from the RFCavity class you should be able to read in a field map. 

In case of the Quadrupole, the fields get calculated from a Multipole (http://amas.web.psi.ch/docs/opal/html/classMultipoleRep.html)

as seen below. So you maybe inherit also from RFCavity or extend the EMField with the required capabilities.

I hope that helps and sorry for the delay but I just returned from a trip and my disk is kind of over-full.

Cheers Andreas 

On Oct 20, 2011, at 9:27 PM, Norman Huang wrote:

Andreas, is there a suitable Opal object I can use to import a static fieldmap?

As you can see in the input file, I'm using an RFCavity to represent the fieldmap of a magnetic quadrupole. This is a temporary hack. If not, then I will implement an OpalStaticField object for this purpose.

Regards,
Norman

---

Subject: Re: Using a 3DDynamic Field Map
From: andreas.adelmann AT psi.ch
Date: Thu, 20 Oct 2011 10:38:20 +0200
CC: srussell AT lanl.gov; krab AT triumf.ca; raoyn AT triumf.ca; tplanche AT triumf.ca
To: norman-huang AT hotmail.com

On Oct 20, 2011, at 8:45 AM, Norman Huang wrote:

I ended up creating a 3DStatic map class by recycling most of the FM3DDynamic code. These modifications were required:
1. There is no oscillation
2. It doesn't scale the field strength by max Ez, since Ez ~= 0 in quadrupoles
This works, we're able to use fieldmaps to generate results that agree with results produced from the analytical quadrupoles. 

ok great that is awesome progress!

Please send me the src file so I can better see what you are exactly doing.

Cheers Andreas 

I still have one problem though... Right now I'm loading the fieldmap through an RFCavity, with Peak Voltage = 1 and Frequency = 0 (avoiding scaling and oscillation). 

This is obviously not an ideal solution. Is there a way to import a fieldmap without having to use an OPAL Element object? If not, is there some sort of 'generic' object that I can use to represent the fieldmap?

Regards,
Norman



Andreas Adelmann <andreas.adelmann AT psi.ch> wrote:

ok great sounds reasonable to mr! This is not a problem anymore and OPAL seams to be ok.

W.r.t. the ES-Quad, just to make things clear: do you need a 3D field or would a cylindric symmetric (r,\theta,z)

be enough?  

Cheers Andreas 

On Oct 19, 2011, at 6:45 PM, Norman Huang wrote:

Hi Andreas,

The focal length f is found with the formula:

1/f = K*L/B_rho

Where K is the gradient and L is the lens length.

K=14.084507 T/m 

L=0.20 m

B_rho=3.45816 Tm
f=1.2276 m

The focal point p is found by measuring the focal length f from the center of the lens. 

p = d1 + 0.5*L +  f = 0.1 + 0.1 + 1.2276 = 1.4276m

The formula for f is a thin lens approximation, this might be a cause of the discrepancy. So I did another run by scaling down L by a factor of 10, and K up by a factor of 10. The new run results in an error of 0.0034m, approximately 0.3%. 

Regards,

Norman

---

Subject: Re: Using a 3DDynamic Field Map
From: andreas.adelmann AT psi.ch
Date: Wed, 19 Oct 2011 03:05:09 +0200
CC: srussell AT lanl.gov; krab AT triumf.ca; raoyn AT triumf.ca; tplanche AT triumf.ca
To: norman-huang AT hotmail.com

Hello Norman, catching up with emails (still in Japan) ... 

Hi everyone,

So we were able to get a somewhat reasonable result using both an analytic electrostatic and magnetic quadrupole, but with some errors in the position of the focal point.

Does reasonable means still with the ~ 3 cm disagreement ?

 

How did you get the results of the magnetic quadrupole i.e. the expected focal point: 1.4276 m please explain.

Cheers Andreas 

We now want to do the same simulations, but use a field map instead of the analytic models. Previously, Andreas had suggested the use of 3DDynamic field map with very low frequency to mimic a 3D Electrostatic field map, as that function is yet to be implemented. 

I was wondering if anyone has an example that actually uses a 3DDyanmic map; all the examples I have on hand are ASTRA maps attached to RFCAVITIES and SOLENOID elements.

Thanks,

Norman

------
Dr. sc. math. Andreas (Andy) Adelmann
Staff Scientist
Paul Scherrer Institut WLGB/132 CH-5232 Villigen PSI
Phone Office: xx41 56 310 42 33 Fax: xx41 56 310 31 91
Phone Home: xx41 62 891 91 44
-------------------------------------------------------
Thursdays: ETH CAB H 83.1  +41 44 632 36 72
============================================
The more exotic, the more abstract the knowledge, 
the more profound will be its consequences.
Leon Lederman 
============================================

------
Dr. sc. math. Andreas (Andy) Adelmann
Staff Scientist
Paul Scherrer Institut WLGB/132 CH-5232 Villigen PSI
Phone Office: xx41 56 310 42 33 Fax: xx41 56 310 31 91
Phone Home: xx41 62 891 91 44
-------------------------------------------------------
Thursdays: ETH CAB H 83.1  +41 44 632 36 72
============================================
The more exotic, the more abstract the knowledge, 
the more profound will be its consequences.
Leon Lederman 
============================================

------
Dr. sc. math. Andreas (Andy) Adelmann
Staff Scientist
Paul Scherrer Institut WLGB/132 CH-5232 Villigen PSI
Phone Office: xx41 56 310 42 33 Fax: xx41 56 310 31 91
Phone Home: xx41 62 891 91 44
-------------------------------------------------------
Thursdays: ETH CAB H 83.1  +41 44 632 36 72
============================================
The more exotic, the more abstract the knowledge, 
the more profound will be its consequences.
Leon Lederman 
============================================

<qf.in><testmap.out><FM3DStatic.cpp>

------
Dr. sc. math. Andreas (Andy) Adelmann
Staff Scientist
Paul Scherrer Institut WLGB/132 CH-5232 Villigen PSI
Phone Office: xx41 56 310 42 33 Fax: xx41 56 310 31 91
Phone Home: xx41 62 891 91 44
-------------------------------------------------------
Thursdays: ETH CAB H 83.1  +41 44 632 36 72
============================================
The more exotic, the more abstract the knowledge, 
the more profound will be its consequences.
Leon Lederman 
============================================