Unknown error in geometry

From: Christopher Knievel (Christopher.Knievel@lightsource.ca)
Date: Tue Apr 01 2003 - 22:03:43 CEST

Dear FLUKA users and authors:

I am having a problem when I run my input with fluka. I am trying to simulate an electron beam interacting with a cylindrical aluminum beam stop. The error which I receive in the .err file is as follows:

 Geofar: Particle in region 3 (cell # 0) in position 5.730835694E+00 9.686117683E+00 3.982049539E+01
  is now causing trouble, requesting a step of 9.549625271E+00 cm
  to direction 1.929431495E-01 7.823632011E-01 5.921830482E-01, error count: 0
  R2: 1.125448149E+01 R3: 4.138037224E+01 cm
  X*U (2D): 8.683787525E+00 X*U (3D): 3.226480986E+01 cm
  X*UOLD(2D): -2.805983023E+00 X*UOLD(3D): 2.332732094E+01 cm
  Kloop: 49, Irsave: 3, Irsav2: 3, error code: -33 Nfrom: 5000
  old direction 4.859413563E-01 -5.772006160E-01 6.562777210E-01, lagain, lstnew, lsense, lsnsct F F F F
  Particle index 7 total energy 7.510855076E-04 GeV Nsurf 0
 Try again to establish the current region moving the particle of a 1.000000000E-06 long step
 We succeeded in saving the particle: current region is n. 3 (cell # 0)

This error continues for many more cycles. In the .out file the error reads as:

 IR= 3 XB= 0.57308359E+01 0.96861185E+01 0.39820496E+02 WB= 0.19294315E+00 0.78236320E+00 0.59218305E+00 DIST= 0.48005062E+01
 IRLTGG= 0 SB= 0.57308359E+01 0.96861185E+01 0.39820496E+02 UB= 0.19294315E+00 0.78236320E+00 0.59218305E+00
 PR 10 0.57308359E+01 0.96861185E+01 0.39820496E+02 0.19294315E+00 0.78236320E+00 0.59218305E+00 3
         3 3 1 -1 1 0 1 54 54 10
        93 101 1 93 95 4 0 105 10 10
-0.31547868E+02 0.48005062E+01 0.48005062E+01 0.48005062E+01

I will attach my input file which I used. I understand that the error means that the program is having problems tracking the particle from point (x,y,z) to point (x',y',z') defined by the directional vectors given above, I just do not know what to do to correct the problem. As one can see from my input, the beam dump should be 61 cm long and it is enclosed in a cylindrical vacuum shell that is 5 cm thick. At least this is what I tried to simulate. Transport should also start at the front of the aluminum cylinder, which is the coordinate (0,0,0). If anyone could assist me with my problem, it would be greatly appreciated.


Christopher Knievel
Health, Safety and Environment Assistant
Canadian Light Source


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