The OPAL Discussion Forum

["Adelmann Andreas (PSI)" <andreas.adelmann AT psi.ch>]

Dear colleagues I soliciting ideas how to handle the case of more than one SurfacePhysics Handler in

a simulation. This problem comes up if one is simulating a degrader with n-material slabs and n-1 gaps (vacuum == drift)

in between. 

As an example consider:

DEGPHYS_Slab1 :  SURFACEPHYSICS, TYPE="DEGRADER", MATERIAL="Graphite";

Wedge1: DEGRADER, L=0.00255124, ZSIZE= 0.00255124, OUTFN="Wedge1.h5", SURFACEPHYSICS=DEGPHYS_Slab1 , ELEMEDGE=4;

Deg_D1: DRIFT, L=0.0360075, ELEMEDGE=4.00255;

MDegD1: MONITOR, OUTFN="MDegD1.h5", ELEMEDGE=4.02055;

DEGPHYS_Slab2 :  SURFACEPHYSICS, TYPE="DEGRADER", MATERIAL="Graphite";

Wedge2: DEGRADER, L=0.00510247, ZSIZE= 0.00510247, OUTFN="Wedge2.h5", SURFACEPHYSICS=DEGPHYS_Slab2, ELEMEDGE=4.03856;

Deg_D2: DRIFT, L=0.0360075, ELEMEDGE=4.04366;

MDegD2: MONITOR, OUTFN="MDegD2.h5", ELEMEDGE=4.06166;

DEGPHYS_Slab3 :  SURFACEPHYSICS, TYPE="DEGRADER", MATERIAL="Graphite";

Wedge3: DEGRADER, L=0.00510247, ZSIZE= 0.00510247, OUTFN="Wedge3.h5", SURFACEPHYSICS=DEGPHYS_Slab3 , ELEMEDGE=4.07967;

Deg_D3: DRIFT, L=0.0360075, ELEMEDGE=4.08477;

MDegD3: MONITOR, OUTFN="MDegD3.h5", ELEMEDGE=4.10277;

DEGPHYS_Slab4 :  SURFACEPHYSICS, TYPE="DEGRADER", MATERIAL="Graphite";

Wedge4: DEGRADER, L=0.00510247, ZSIZE= 0.00510247, OUTFN="Wedge4.h5", SURFACEPHYSICS=DEGPHYS_Slab4 , ELEMEDGE=4.12078;

Deg_D4: DRIFT, L=0.0360075, ELEMEDGE=4.12588;

MDegD4: MONITOR, OUTFN="MDegD4.h5", ELEMEDGE=4.14388;

DEGPHYS_Slab5 :  SURFACEPHYSICS, TYPE="DEGRADER", MATERIAL="Graphite";

Wedge5: DEGRADER, L=0.00510247, ZSIZE= 0.00510247, OUTFN="Wedge5.h5", SURFACEPHYSICS=DEGPHYS_Slab5 , ELEMEDGE=4.16189;

Deg_D5: DRIFT, L=0.0360075, ELEMEDGE=4.16699;

MDegD5: MONITOR, OUTFN="MDegD5.h5", ELEMEDGE=4.18499;

DEGPHYS_Slab6 :  SURFACEPHYSICS, TYPE="DEGRADER", MATERIAL="Graphite";

Wedge6: DEGRADER, L=0.00255124, ZSIZE= 0.00255124, OUTFN="Wedge6.h5", SURFACEPHYSICS=DEGPHYS_Slab6 , ELEMEDGE=4.203;

Alumina1: DRIFT, L=0.0003, ELEMEDGE=4.20555;

MDegD6: MONITOR, OUTFN="MDegD6.h5", ELEMEDGE=4.30585;

DEGRADER: LINE=(Wedge1,Deg_D1,MDegD1,Wedge2,Deg_D2,MDegD2,Wedge3,Deg_D3,MDegD3,Wedge4,Deg_D4,MDegD4,Wedge5,Deg_D5,MDegD5,Wedge6,Alumina1,MDegD6);

Now such an problem leads to an error in the ParallelTTracker at line 2009 ERRORMSG(“Internal …. ):

if(hasSurfacePhysics > 0) {    // in a section we have an element with surface physics                                                                   

        if(!surfaceStatus_m) {

            msg << level2 << "============== START SURFACE PHYSICS CALCULATION =============" << endl;

            surfaceStatus_m = true;

            // now get surface physics handler                                                                                                               

            reduce(sphysSection, sphysSection, OpMaxAssign());

            if (sphys_m==NULL)

                sphys_m = itsOpalBeamline_m.getSurfacePhysicsHandler(sphysSection);

            else {

                /* FixMe: this needs to be redone !                                                                                                          

                In case we have an other                                                                                                                     

                handler, delete the first one and use the new one                                                                                            

                */

                ERRORMSG("Internal error: try to allocate second SurfacePhysicsHandler - SRCFILE" << __FILE__ << " LINE " << __LINE__ << endl);

                SurfacePhysicsHandler *sphysNew = itsOpalBeamline_m.getSurfacePhysicsHandler(sphysSection);

                if (sphysNew != sphys_m && sphysNew != NULL) {

                    //delete sphys_m; FixMe: should do this right!!!                                                                                         

                    sphys_m = sphysNew;

                }

            }

        }

if(sphys_m == NULL) {

            INFOMSG("no surface physics attached" << endl);

        } else {

            sphys_m->apply(*itsBunch);

            sphys_m->print(msg);

        }

    } else if(surfaceStatus_m) {

        if (sphys_m->stillActive()) {

            sphys_m->apply(*itsBunch);

            sphys_m->print(msg);

        } else {

            msg << level2 << "============== END SURFACE PHYSICS CALCULATION =============" << endl;

            surfaceStatus_m = false;

        }

    }

I think we have to distinguish 2 cases: 

a) the beam is in 2 or more materials at the same time.

—> this Ansatz will not work at all

b) In case the beam is always only in one material we. In that case we

    need to find the correct SurfacePhysicsHandler. 

—> maybe based on the extend of the beam? 

For interested colleagues with good ideas I propose a google hangout at 3pm (CET) on June 25 or of course

a lively discussion on the mailing list.

Cheers 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
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