Tracking for DA study

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ccwang
Posts: 12
Joined: 09 Jan 2009, 05:10

Re: Tracking for DA study

Post by ccwang » 17 Jan 2009, 03:52

Dear Michael,

Just to express my question more clearly. Since "csbend" is canonical, it seems to me "csbend will get more correct estimation in anyway, small and big rings, is it right?

When I did the DA study, my results with "sbend" is more close to AT results but DA is x direction is only about 40% with "csbend" compare to "sbend". Since my usage of csbend is with non-zero k1 , does it really affect ?

Thanks a lot!
Chinchi

michael_borland
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Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: Tracking for DA study

Post by michael_borland » 18 Jan 2009, 18:50

Chinchi,

CSBEND = Canonical Sector BEND. It uses a canonical integration technique (Ruth integrator) to model the dipole, giving symplectic behavior and energy-dependence to all orders.

SBEN = Sector BEND modeled using transport matrices, up to second order. It is fine for transport lines or computing chromatic properties of rings (e.g., twiss_output).

--Michael

michael_borland
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Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: Tracking for DA study

Post by michael_borland » 18 Jan 2009, 18:56

ccwang wrote:Dear Michael,

Just to express my question more clearly. Since "csbend" is canonical, it seems to me "csbend will get more correct estimation in anyway, small and big rings, is it right?

When I did the DA study, my results with "sbend" is more close to AT results but DA is x direction is only about 40% with "csbend" compare to "sbend". Since my usage of csbend is with non-zero k1 , does it really affect ?

Thanks a lot!
Chinchi
Chinchi,

Yes, CSBEND will give the most accurate results. However, for big rings it isn't necessary and just makes the tracking slower.

I'm not sure why SBEND would agree more with AT, since I don't know how AT models dipoles. I would assume that it uses a canonical integration technique. For other rings, elegant CSBEND results have shown good agreement with AT and TRACY.

--Michael

ccwang
Posts: 12
Joined: 09 Jan 2009, 05:10

Re: Tracking for DA study

Post by ccwang » 02 Feb 2009, 03:14

Dear Michael,

In my case, I use CSBEND with non-zero k1 and k2. I guess probably it is the reason.

BTW, is there any example of off momentum particle DA study? I would like to check the particle behavior with +-3% energy difference. Thanks a lot!

Best wishes,
Chinchi

michael_borland
Posts: 1735
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
Contact:

Re: Tracking for DA study

Post by michael_borland » 02 Feb 2009, 12:06

Chinchi,

Please see the attached files for an example of off-momentum DA.

--Michael
Attachments
offMomentumDA.tar.gz
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