The OPAL Discussion Forum

["frederic.le.pimpec" <frederic.le.pimpec AT psi.ch>]

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