[neutron-mc] Generate a source spectra from exp. file

[Philip Wilk]

It is not working for me. It seems to add to it, rather then set it.

I just put this at the top of the file right?

# lambda set

and it sets the options?

Regards,
Philip
  ----- Original Message ----- 
  From: Emmanuel Farhi 
  To: pwilk at zenspider.com ; neutron-mc at risoe.dk 
  Sent: Wednesday, August 27, 2003 11:07 AM
  Subject: [neutron-mc] Generate a source spectra from exp. file


  Yes, there is a solution to use an experimental profile for the simulation source. 
  First position a normal source (Source_flat or Source_gen, or ...). 
  Then, you may use the Filter_gen component (in the optics) to read the contents a a file, with options="lambda, set weight". Then the first column of the table is assumed to be the wavelength, and the second should be the flux to set. 
  A rebinning/interpolation is done when loading the table. This will set the weight of neutrons. You may also choose to multiply or add to the existing weight. 
  The Filter_gen (McStas v1.7) is a replacement to the old Flux_adapter. 

  Just look at the MCSTASLIB/optics/Filter_gen component (or 'mcdoc Filter_gen'). 

  pwilk wrote: 

    Thanks for the quick reply! I'll give that a go.I think you are right about the zero velocity neutrons.I have another quick question for you: Is there an easy way to simulate a source from a 2D file of (measured) Intensity vs. Wavelength ?Cheers,Philip 
      -----Original Message----- 
      From: farhi at ill.fr [mailto:farhi at ill.fr] 
      Sent: Tuesday, August 26, 2003 3:18 PM 
      To: pwilk-radiochem at hahnium.com; neutron-mc at risoe.dk 
      Subject: Re: sqrt: DOMAIN error
      Hy Philip, 
      You probably have some zero velocity neutrons or such huge velocities that the square gets hawfull (before getting the sqrt), else I can not figure out how the 'sqrt' can fail in the speed in L_monitor.comp. 
      You may copy this component locally and change the line #76 so that it tests the speed norm to be non zero or reasonable value (not huge). 

      You may also try replacing with the Monitor_nD(options="auto lambda", filename="...") 

      Cheers, Emmanuel. 

      Philip Wilk wrote: 

        Hi, 
        I am using the new version 1.7 

        I keep getting "sqrt: DOMAIN error" 

        Just like I was getting with version 1.6.4 , should I be worried about this? 
        It seems to be associated with the wavelength detector component. 

        See example output: 

        Detector: psd_begin_I=75.9887 psd_begin_ERR=0.0701353 
        psd_begin_N=3.65191e+06 "p 
        sd1.dat" 
        Detector: lambda_begin_I=75.9887 lambda_begin_ERR=0.0701353 
        lambda_begin_N=3.651 
        91e+06 "erg1.dat" 
        Detector: psd_middle_I=6.2552 psd_middle_ERR=0.017862 
        psd_middle_N=1.68387e+06 " 
        psd2.dat" 

        sqrt: DOMAIN error 
        Detector: lambda_middle_I=6.2552 lambda_middle_ERR=0.017862 
        lambda_middle_N=1.68 
        387e+06 "erg2.dat" 
        Detector: psd_middle2_I=1.20321 psd_middle2_ERR=0.00418768 
        psd_middle2_N=1.08584 
        e+06 "psd3.dat" 
        Detector: lambda_middle2_I=1.20321 lambda_middle2_ERR=0.00418768 
        lambda_middle2_ 
        N=1.08584e+06 "erg3.dat" 
        Detector: psd_end_I=0.65266 psd_end_ERR=0.002805 psd_end_N=389221 "psd4.dat" 
        Detector: lambda_end_I=0.65266 lambda_end_ERR=0.002805 lambda_end_N=389221 
        "erg4 
        .dat" 

        Cheers, 
        Philip

-- 
What's up Doc ?
--------------------------------------------
Emmanuel FARHI, http://www.ill.fr/tas/people/Farhi.html   \|/ ____ \|/
CS-Group ILL4/156, Institut Laue-Langevin (ILL) Grenoble  ~@-/ oO \-@~
6 rue J. Horowitz, BP 156, 38042 Grenoble Cedex 9,France  /_( \__/ )_\
Work :Tel (33/0) 4 76 20 71 35. Fax (33/0) 4 76 20 76 48     \__U_/ 
-- 
What's up Doc ?
--------------------------------------------
Emmanuel FARHI, http://www.ill.fr/tas/people/Farhi.html   \|/ ____ \|/
CS-Group ILL4/156, Institut Laue-Langevin (ILL) Grenoble  ~@-/ oO \-@~
6 rue J. Horowitz, BP 156, 38042 Grenoble Cedex 9,France  /_( \__/ )_\
Work :Tel (33/0) 4 76 20 71 35. Fax (33/0) 4 76 20 76 48     \__U_/  
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