The OPAL Discussion Forum

["Russell, Steve" <srussell AT lanl.gov>]

Hi Nicole,

TPULSEFWHM has the same meaning for a GAUSS distribution as it does for
a FLATTOP distribution.

If you set TPULSEFWHM = 0.0, as you suggest, for the FLATTOP
distribution, that should work.

Steve


On Wed, 2015-11-18 at 13:37 -0600, Nicole Neveu wrote:
> Andreas, 
> 
> 
> ​Regarding you cutoff question, here is some more information about
> the beam we are trying to create: 
> 
> 
> Transverse: Flattop with radius of 2mm
> Longitudinal: Gaussian with FWHM 8ps (no flattop). 
> 
> 
> If you think there is a better way to define this distribution, it'd
> be great to hear your advice.
> We didn't use the flattop distribution because we want a Gaussian with
> no flattop in the longitudinal direction.
> Would it be more efficient to use a Flatttop distribution with
> TPULSEFWHM set to 0.0? 
> Would that leave only leave only the Gaussian portion? 
> 
> 
> I think TPULSEFWHM sets the traditional FWHM in the GUASSIAN
> distribution. 
> In the FLATTOP distribution, I think TPULSEFWHM only sets the
> longitudinal flattop time,
> and the Gaussian portion is defined by TRISE/TFALL (example on pg 119
> of manual). 
> 
> 
> Is that correct?
>   
> 
> Thanks,
> 
> 
> Nicole
> 
> 
> 
> 
> 
> On Wed, Nov 18, 2015 at 12:20 PM, Nicole Neveu <nneveu AT hawk.iit.edu>
> wrote:
>         Andreas, 
>         
>         
>         You are definitely right. I should have changed the number of
>         particles and turned on the FFT solver. 
>         This is something I fixed in later versions of my file, sorry
>         for the confusion. ​
>         So this file ran on several nodes on your cluster? I will try
>         again with the above corrections.
>         
>         
>         As for the cutoffs, an initial beam radius of 2mm was
>         requested, and that's what I used to set the cutoffs. 
>         Did I set those incorrectly? This is a parameter that might be
>         adjusted depending on the initial simulation results.
>         
>         
>         Thanks, 
>         
>         
>         Nicole
>         ​
>         
>         On Wed, Nov 18, 2015 at 10:58 AM, Adelmann Andreas (PSI)
>         <andreas.adelmann AT psi.ch> wrote:
>                 Dear Nicole
>                 
>                 
>                 In case you are running 1000 particles and no field
>                 solver and using 16 cores does not make sense and 
>                 is most probable the cause of your problem.
>                 
>                 
>                 At the moment I am running 16 & 32 cores, on a 32^3
>                 grid with 1E6 particles.
>                 A node on your cluster has 16 cores. I copy YAGT.h5
>                 and OTR.stat into you 
>                 Dropbox for the 32P 1E6 simulation.
>                 
>                 
>                 Also I note, you are using a Gauss distribution with a
>                 CUTOFF in X and Y which
>                 is very tight. As a consequence, it takes a long time
>                 to generate the distribution. 
>                 Is that necessary? 
>                 
>                 
>                 ECollimator works (in 1.4) and yes you can overlap 
>                 collimators with other elements.
>                  
>                 Here the modified distribution:
>                 OPAL{0}> * ************* D I S T R I B U T I O N
>                 ********************************************
>                 OPAL{0}> * 
>                 OPAL{0}> * Number of particles: 1000000
>                 OPAL{0}> * 
>                 OPAL{0}> * Distribution type: GAUSS
>                 OPAL{0}> * 
>                 OPAL{0}> * Sigma Time Rise               = 3.40265e-12
>                 [sec]
>                 OPAL{0}> * TPULSEFWHM                    = 8e-12 [sec]
>                 OPAL{0}> * Sigma Time Fall               = 3.40265e-12
>                 [sec]
>                 OPAL{0}> * Longitudinal cutoff           = 4 [units of
>                 Sigma Time]
>                 OPAL{0}> * Flat top modulation amplitude = 0 [Percent
>                 of distribution amplitude]
>                 OPAL{0}> * Flat top modulation periods   = 0
>                 OPAL{0}> * SIGMAX                        = 0.002 [m]
>                 OPAL{0}> * SIGMAY                        = 0.002 [m]
>                 OPAL{0}> * SIGMAPX                       = 0 [Beta
>                 Gamma]
>                 OPAL{0}> * SIGMAPY                       = 0 [Beta
>                 Gamma]
>                 OPAL{0}> * CORRX                         = 0
>                 OPAL{0}> * CORRY                         = 0
>                 OPAL{0}> * CUTOFFX                       = 1 [units of
>                 SIGMAX]
>                 OPAL{0}> * CUTOFFY                       = 1 [units of
>                 SIGMAY]
>                 OPAL{0}> * CUTOFFPX                      = 0 [units of
>                 SIGMAPX]
>                 OPAL{0}> * CUTOFFPY                      = 0 [units of
>                 SIGMAPY]
>                 OPAL{0}> * 
>                 OPAL{0}> * Number of energy bins    = 9
>                 OPAL{0}> * Distribution is emitted. 
>                 OPAL{0}> * Emission time            = 2.72085e-11
>                 [sec]
>                 OPAL{0}> * Time per bin             = 3.02317e-12
>                 [sec]
>                 OPAL{0}> * Delta t during emission  = 5.49668e-14
>                 [sec]
>                 OPAL{0}> * 
>                 OPAL{0}> * ------------- THERMAL EMITTANCE MODEL
>                 --------------------------------------------
>                 OPAL{0}> *  THERMAL EMITTANCE in NONEQUIL MODE
>                 OPAL{0}> *  Cathode work function     = 3.2 [eV]  
>                 OPAL{0}> *  Cathode Fermi energy      = 3.2 [eV]  
>                 OPAL{0}> *  Cathode temperature       = 321.95 [K]  
>                 OPAL{0}> *  Photocathode laser energy = 5 [eV]  
>                 OPAL{0}> *
>                 
> ----------------------------------------------------------------------------------
>                 OPAL{0}> * 
>                 OPAL{0}> * 
>                 OPAL{0}> *
>                 
> **********************************************************************************
>                 OPAL{0}> 
>                 OPAL{0}> * ************* B E A M
>                 
> ************************************************************ 
>                 OPAL{0}> * BEAM        BEAM1
>                 OPAL{0}> * PARTICLE    ELECTRON
>                 OPAL{0}> * CURRENT     1.3 A
>                 OPAL{0}> * FREQUENCY   1.3e+09 Hz
>                 OPAL{0}> * CHARGE      -e * 1 
>                 OPAL{0}> * REST MASS   0.000510999 GeV
>                 OPAL{0}> * MOMENTUM    1.01094e-06
>                 OPAL{0}> * NPART       1e+06
>                 OPAL{0}> *
>                 
> **********************************************************************************
>  
>                 OPAL{0}> 
>                 OPAL{0}> * ************* F I E L D S O L V E R
>                 ********************************************** 
>                 OPAL{0}> * FIELDSOLVER  FS_SC
>                 OPAL{0}> * TYPE         FFT
>                 OPAL{0}> * N-PROCESSORS 32
>                 OPAL{0}> * MX           32
>                 OPAL{0}> * MY           32
>                 OPAL{0}> * MT           32
>                 OPAL{0}> * BBOXINCR     1
>                 OPAL{0}> * GRRENSF      INTEGRATED
>                 OPAL{0}> * XDIM         parallel  
>                 OPAL{0}> * YDIM         parallel  
>                 OPAL{0}> * Z(T)DIM      serial  
>                 OPAL{0}> 
>                 OPAL{0}> *
>                 
> **********************************************************************************
>  
>                 OPAL{0}> 
>                 OPAL{0}> 
>                 OPAL{0}> Track start at: 15:54:06, t= 0; zstop at: 3
>                 [m]
>                 ParallelTTracker {0}> Change dT from 1e-13 [s] to
>                 5.49668e-14 [s] during emission 
>                 OPAL{0}> Executing ParallelTTracker, initial DT 1e-13
>                 [s];
>                 OPAL{0}> max integration steps 190000, next step= 0
>                 OPAL{0}> Using default (Boris-Buneman) integrator
>                 
>                 
>                 Please let me know if that makes sense.
>                 
>                 
>                 With the best regards 
>                 Andreas 
>                 
>                 ------
>                 Dr. sc. math. Andreas (Andy) Adelmann
>                 Staff Scientist
>                 Paul Scherrer Institut WBBA/219 CH-5232 Villigen PSI
>                 Phone Office: xx41 56 310 42 33 Fax: xx41 56 310 31 91
>                 Phone Home: xx41 62 891 91 44
>                 -------------------------------------------------------
>                 Friday: ETH CAB H 85.1  +41 44 632 75 22
>                 ============================================
>                 The more exotic, the more abstract the knowledge, 
>                 the more profound will be its consequences.
>                 Leon Lederman 
>                 ============================================
>                 
>                 > On 17 Nov 2015, at 09:01, Andreas Adelmann
>                 > <andreas.adelmann AT psi.ch> wrote:
>                 > 
>                 > Hello Nicole 
>                 > 
>                 > 
>                 > > 
>                 > > ​Hello OPAL experts,
>                 > >  
>                 > > I've been using OPAL for the past few months and
>                 > > things are going well. Thanks again for your help
>                 > > with my thermionic gun simulations when I first
>                 > > started. I am currently running V1.2, but plan to
>                 > > switch to V1.4 when it is released. I have a few
>                 > > questions about the differences, ect.
>                 > 
>                 > 
>                 > Yes 1.4 is a bit late :( but we are close :-)
>                 >  
>                 > > 1. Does OPAL scale magnetic field maps to the max
>                 > > B value in the file, or max Bz on axis? Pg. 183 of
>                 > > the manual says: "the input field map will be
>                 > > normalized so the peak field magnitude value is
>                 > > equal to ...1 T in the case of magnetic field
>                 > > maps."  I think I see this behavior in my
>                 > > simulations, but appendix C (pg. 203) says scaling
>                 > > is done using max Bz on axis values. Is this a
>                 > > feature that is changed from V1.2 to V1.4?
>                 > 
>                 > 
>                 > The behaviour is as described on P. 183 and the
>                 > description on P 203 is corrected in the new version
>                 > of the manual.
>                 > 
>                 > 
>                 > @Steve: can you check please 
>                 > 
>                 > 
>                 > 
>                 > >  
>                 > > 2. Should I use the R or E collimator? When we
>                 > > were emailing about the thermionic gun, it was
>                 > > suggested that I use the R collimator. The manual
>                 > > says E is supported in OPAL-T (pg.98). Is this
>                 > > difference an artifact of using V1.2? 
>                 > 
>                 > 
>                 > In 1.4 you can use both, indeed there was a problem
>                 > in 1.2.
>                 > 
>                 > 
>                 > > 3. I have been running on a cluster at ANL,
>                 > > and I've been able to run on multiple processors,
>                 > > but not on multiple nodes. I get segmentation
>                 > > faults (11). Is this an artifact of using V1.2
>                 > > that will be fixed in V1.4, or is it something I
>                 > > am doing wrong?  The cluster uses Torque PBS
>                 > > manager and Maui PBS scheduler, and my run
>                 > > commands look like the following:
>                 > > mpirun -np 16 opal OTR.in --info 0 | tee OTR.out
>                 > > 
>                 > > 
>                 > 
>                 > 
>                 > That should work. Are you using the pre-build
>                 > binaries for the closure runs? 
>                 > If you send me the input file I can have a look and
>                 > check on our cluster.
>                 > Also tell me where do you want to have the
>                 > E-collimator so I can try. 
>                 > Do we have a Dropbox?
>                 > 
>                 > 
>                 > Cheers Andreas 
>                 
>                 
>         
>         
> 
>