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Re: [Opal] Dark Current Simulations - FE


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  • From: "frederic.le.pimpec" <frederic.le.pimpec AT psi.ch>
  • To: "frederic.le.pimpec" <frederic.le.pimpec AT psi.ch>
  • Cc: wangchuan02513 <wangchuan02513 AT 163.com>, Andreas Adelmann <andreas.adelmann AT psi.ch>, opal AT lists.psi.ch
  • Subject: Re: [Opal] Dark Current Simulations - FE
  • Date: Tue, 13 Sep 2011 16:38:11 +0200
  • List-archive: <https://lists.web.psi.ch/pipermail/opal/>
  • List-id: The OPAL Discussion Forum <opal.lists.psi.ch>
  • Organization: PSI

Hi Chuan,
the .o34199 (opal run output) shows

NPART 50 # Number of simulation particles in bunch
> QBUNCH 0.1 # Bunch charge [pC]
> OPAL {0}> MINSTEPFORREBIN 1000
> OPAL {0}> REPARTFREQ 2

and the plots is still the same as the one sent previously
the .o34199 (opal run output) shows the same thing
I have 500 steps before the emission really starts.following the RF phase.

It should not, OPAL should accept the quick emission of particles according to
DTGUN 1.0 # time step in gun [ps]
after emitting my 50 particles totalizing 0.1 pC of electrons

hence after the first few steps the RF should vary every ps !

Any idea how to solve this issue ?

bests
Frederic

frederic.le.pimpec wrote:
Hi Chuan,

I re-run the dark current simulation of the RG gun using in the data file
#
NPART 50 # Number of simulation particles in bunch
QBUNCH 0.1 # Bunch charge [pC]

so Normally I should have had after 2 steps the full emission of my bunch and then the dark current should start ... and each step should be 1ps instead of a % of a ps.

As can be seen on the attached figure the emission is constant during 500 steps.
looking at the emission time it also changes to a ps after step 499

the .o33394 (opal run output)

Boundary geometry initialized
OPAL {0}> MINSTEPFORREBIN 1000
OPAL {0}> REPARTFREQ 500
OPAL {0}> Changing emission time step to: 1.3927e-14
OPAL {0}> * Emit 281 particles at the surfaces
OPAL {0}> Step 0 no emission yet t= 1.3927e-14 [s]
OPAL {0}> * Emit 281 particles at the surfaces
OPAL {0}> 15.08.52 Step 1 at 0 [m] t= 2.78539e-14 [s] E=4.18961e-08 [MeV]
OPAL {0}> * Wrote beam phase space.
OPAL {0}> * ************** B U N C H *********************************************************
OPAL {0}> * NP= 562 Qtot= 0.002832 [nC] Qi= 2e-15 [C]
OPAL {0}> * spos= 0 [m]
OPAL {0}> * **********************************************************************************
OPAL {0}>
OPAL {0}> * Wrote beam statistics.
OPAL {0}> * Emit 281 particles at the surfaces
OPAL {0}> 15.08.53 Step 2 at 0 [m] t= 4.17809e-14 [s] E=1.04709e-07 [MeV]
OPAL {0}> * Wrote beam phase space.
OPAL {0}> * ************** B U N C H *********************************************************
OPAL {0}> * NP= 843 Qtot= 0.004248 [nC] Qi= 2e-15 [C]
OPAL {0}> * Ekin= 6.98057e-08 [MeV] dEkin= 9.3267e-08 [MeV]
OPAL {0}> * spos= 0 [m]

The first deleted particle appears after step 597
That is fine.

I think the problem is the REPARTFREQ 500 in the .tmpl file

The question is : what is this REPARTFREQ ?
can I set it up to 2 ? (I will anyway and see what happen)

bests
Frederic

--
---------------------------
Dr Frederic Le Pimpec
Paul Scherrer Institut
WBBA 315
5232 Villigen
Switzerland
http://fel.web.psi.ch/
Tel : +41 56 310 5130
FAX : +41 56 310 4488




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