From robert.dalgliesh at stfc.ac.uk Thu Nov 13 11:45:36 2008 From: robert.dalgliesh at stfc.ac.uk (Dalgliesh, RM (Robert)) Date: Thu, 13 Nov 2008 10:45:36 -0000 Subject: [mcstas-users] bug in pol_bender Message-ID: <57BFD82EEF0CDE41A72C4EDADF8A01B207410D13@exchange27.fed.cclrc.ac.uk> The attached code illustrates a considerable set of bugs in the polarising bender code. The components seems to be ok (ish) if the number of channels in the bender is > 1 but it is still possible to get neutrons trapped when a large radius of curvature is used. I've had to put in a check to kill neutron that bounce excessively otherwise simulations stall. I haven't managed to track the source of the bug as there are such a large number of call outs to other routines within the code particularly to the routines that work out cylinder intercepts and gravity. Basically there are a number of manifestations. 1) Neutrons can pass out of the guide without being reflected (run a trace to see this) 2) in an open guide neutrons can get trapped in open space 3) neutrons multi-bounce along walls for no good reason. This is all accentuated when a large radius of curvature is used. Sorry to be no help at all on this one. Rob --------------------------------------------- Dr. Robert Dalgliesh ISIS Rutherford Appleton Laboratory Chilton Didcot Oxfordshire OX11 0QX Tel: +44(0)1235 445687 Fax: +44(0)1235 445720 e-mail: r.m.dalgliesh at rl.ac.uk -- Scanned by iCritical. -------------- next part -------------- A non-text attachment was scrubbed... Name: bender_bug.instr Type: application/octet-stream Size: 3801 bytes Desc: bender_bug.instr URL: From robert.dalgliesh at stfc.ac.uk Thu Nov 13 11:19:34 2008 From: robert.dalgliesh at stfc.ac.uk (Dalgliesh, RM (Robert)) Date: Thu, 13 Nov 2008 10:19:34 -0000 Subject: [mcstas-users] bug in pol_bender Message-ID: <57BFD82EEF0CDE41A72C4EDADF8A01B205431DA6@exchange27.fed.cclrc.ac.uk> The attached code illustrates a considerable set of bugs in the polarising bender code. The components seems to be ok (ish) if the number of channels in the bender is > 1 but it is still possible to get neutrons trapped when a large radius of curvature is used. I've had to put in a check to kill neutron that bounce excessively otherwise simulations stall. I haven't managed to track the source of the bug as there are such a large number of call outs to other routines within the code particularly to the routines that work out cylinder intercepts and gravity. Basically there are a number of manifestations. 1) Neutrons can pass out of the guide without being reflected (run a trace to see this) 2) in an open guide neutrons can get trapped in open space 3) neutrons multi-bounce along walls for no good reason. This is all accentuated when a large radius of curvature is used. Sorry to be no help at all on this one. Rob --------------------------------------------- Dr. Robert Dalgliesh ISIS Rutherford Appleton Laboratory Chilton Didcot Oxfordshire OX11 0QX Tel: +44(0)1235 445687 Fax: +44(0)1235 445720 e-mail: r.m.dalgliesh at rl.ac.uk -- Scanned by iCritical. -------------- next part -------------- A non-text attachment was scrubbed... Name: bender_bug.instr Type: application/octet-stream Size: 3801 bytes Desc: bender_bug.instr URL: From farhi at ill.eu Tue Dec 2 10:32:37 2008 From: farhi at ill.eu (Emmanuel FARHI) Date: Tue, 02 Dec 2008 10:32:37 +0100 Subject: [mcstas-users] Re: [NOBUGS] McStas Selftest error - need help In-Reply-To: <6595f1f40812012331n71e527b0uebbbfe0d38779f08@mail.gmail.com> References: <6595f1f40812012331n71e527b0uebbbfe0d38779f08@mail.gmail.com> Message-ID: <493500B5.6090802@ill.eu> An HTML attachment was scrubbed... URL: From habicht at hmi.de Wed Dec 10 17:33:39 2008 From: habicht at hmi.de (Klaus Habicht) Date: Wed, 10 Dec 2008 17:33:39 +0100 Subject: [mcstas-users] bugs for Monochromator_curved.comp and Guide_tapering.comp Message-ID: <493FEF63.30805@hmi.de> Dear all, I believe there is a bug in Monochromator_curved.comp: Executing mcdisplay on an instrument with Monochromator_curved.comp gives incident trajectories which all end at the middle monochromator blade. Outgoing trajectories seem to be correct since they emerge from the whole assembly. I believe there is a bug in Guide_tapering.comp: The calculated exit width (a parameter called "Weigth at the guide exit (w2)" in my case 0.022288) is wrong. For the example: COMPONENT Elliptically_Tapered_Guide = Guide_tapering( option = "elliptical", segno = 100, w1 = WGUIDE, h1 = 0.125, l = 2.5, linw = 10000, loutw = 0.4, linh = 10000, louth = 10000) AT (0, 0, 0) RELATIVE NL1B_Elliptical_Entrance_Window ROTATED (0, 0, 0) RELATIVE NL1B_Elliptical_Entrance_Window the analytical formula gives 0.0304 m for the exit width. With best regards, Klaus Habicht ------------------------------------------------------------------ Dr. Klaus Habicht Helmholtz-Zentrum Berlin f?r Materialien und Energie SF1 Methods and Instruments Glienicker Strasse 100 D-14109 Berlin Germany Phone office +49 30 8062 2807 instrument +49 30 8062 3122 Fax +49 30 8062 3094 ============================================ Helmholtz-Zentrum Berlin f?r Materialien und Energie GmbH Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V Vorsitzende des Aufsichtsrates: Dr. Beatrix Vierkorn-Rudolph, Gesch?ftsf?hrer: Prof. Dr. Michael Steiner, Dr. Ulrich Breuer Sitz Berlin, AG Charlottenburg, 89 HRB 5583 ============================================