Recent Upgrade of g4lbnf: Horn B Conceptual Design revision 2 Paul - - PowerPoint PPT Presentation

December 15/23 2016 Realistic Horns in G4LBNF 1

Recent Upgrade of g4lbnf: Horn B Conceptual Design revision 2

Paul Lebrun ND/Fermilab.

December 15/23 2016 Realistic Horns in G4LBNF 2

Outline

✔

Horn B, revision 2 => Coded up. ==> geantino plots

✔

(Horn A, small improvements to the code. )

✔

Comparison, Horn “ideal” (as coming out of the genetic algorithm based optimization

• f Laura F. et al) vs “Realistic”, detailed G4 implementation of all “relevant” volumes

found in the NX-9 CAD model, and corresponding changes to the magnetic field map.

✔

Next steps:

–

Implement Horn C, concept. design, Rev 2

–

Retune a bit (spacing between horns, small changes in horn length)

–

Study the effect of field maps upgrades in the Inner/Outer conductor regions, and other non-unformities

December 15/23 2016 Realistic Horns in G4LBNF 3

… Few programming notes..

✔

Now using Geant4 v 4.10.2.p02 .. The change I made to the code caused crashed using the previous release, due to bug in the G4 geometry navigation code, fixed months ago...

✔

So, I am using ROOT 6.x, and a newer compiler, as I haven't found a matching DK2Nu with the old old ROOT and this new compiler.

– This might break the old style nutrino N-tuples code. My

advice: use the Dk2NU package from now on.

✔

I haven't not yet committed the changes.. Bigger change then just G4. Laura F. has upgraded our neutrino analysis script(s), but... is it in use??

December 15/23 2016 Realistic Horns in G4LBNF 4

… Coding the realistic geometry..

✔

No changes in the methodology.. Fired up the Citrix server, TeamCenter, get to the model #, run Nx9, and do the measurements that are needed.. TeamCenter Doc# entered in the code.

✔

Enter the geometry, mostly “hardcoded” in the LBNEVolumePlacements class. One by one, trying to check every number twice...

– Curves ==> Polygonal shape.

✔

Conceptual Design Rev1 no longer avialable at run time: if needed, you'll need to re0build g4lbne from a previous release (v3r4p4 ?.. )

✔

(a good thing a few of us will stay around for the next ~30 years).

December 15/23 2016 Realistic Horns in G4LBNF 5

Nx9 screen captures... (Horn B)

I/O trans. Outer Conductor Inner Conductor Current Eq section 1 m. I/O Insulator

December 15/23 2016 Realistic Horns in G4LBNF 6

..found wire frame a bit more convenient..

Nx9 has good interactive feature to explore the model...Not all features are implemented in the G4 model: simplified some curve, beveled edges for flanges. Also, drain holes not implemented Hanger rings Welds

December 15/23 2016 Realistic Horns in G4LBNF 7

..comparison with Geantinos plots..

Nx9 cut view G4lbnf geantinos R/Z plot Spider hanger added.. (NuMI)

December 15/23 2016 Realistic Horns in G4LBNF 8

Neutrino (in neutrino mode) spectrum, far detector.

Idealistic vs Realistic

Simply replace the Idealistic (as taken of the “run26_8079_NumiTarget” from Laura). All horns are either “ideal” shape (polygonal, from the optimizer) or Real (Nx9 models) Horn A & B are revision 2, Horn C is revision 1.

December 15/23 2016 Realistic Horns in G4LBNF 9

Neutrino (in neutrino mode) spectrum, far detector. Idealistic / Realistic

Simply replace the idealistic horns, as specific in “CP_run26_8079_NumiTarget.mac” Laura gave us (Cory C., my self), by the “Nx9-based” G4 implementation. Note: HornC is still at Revision 1 (slightly inconsistent with that results from the

• ptimization), while Horn A & B are at Rev 2 (Team Center #F10068454,

#F10071359, respectively.

December 15/23 2016 Realistic Horns in G4LBNF 10

.. On a wider scale...

Biggest change is in the tail for the focusing peak. We are gaining at ~ 4 GeV/c , then loosing up to 50%, but then, rather flat. This is the energy regime where we are most sensitive to focusing effects!. (previous studies..)

December 15/23 2016 Realistic Horns in G4LBNF 11

Details needed! What Changed?

Horn B move from ideal to realistic seems to have the smallest impact (< 10 % change, in the focusing peak.. Horn A similar, in the focusing peak, at least. This what one more or less expects (again, previous studies..) due to matter effect (absorption of good pions..., on I/O sections, welds, supports.... )

December 15/23 2016 Realistic Horns in G4LBNF 12

An other way to compare.. : Two horns “realistic”, one “idealized”

Regards to the changes in the high energy tail, it seems obvious that Horn C needs

• revision. Not suprising is the ovbious candiate to work on: If idealized, this is “rev2”,

if “Realistic”, still from Rev 1. ==> “field map differ”.

December 15/23 2016 Realistic Horns in G4LBNF 13

Effect of downstream target support..

<~ 1 % change across the spectrum! Perhaps sensible: In the focusing peak, pions at a bigger radii than the bulk of the support, which at a Radius of ~ 40 mm. Not affected.. At higher energy production of pions that can be focused by HornC do compensate the absorption. And, of course, no magnetic effects.

December 15/23 2016 Realistic Horns in G4LBNF 14

Focusing changes: Effective magnetic length of horns.. Ideal vs realistic..

In the ideal version, the I/O transitions region are much simplified, they are nearly vertical

• lines. We (Cory C. ? ) could compromise and reduce a bit the length of the IC, to match

the same B.dl that enter (or leaving) the I/O transition..

December 15/23 2016 Realistic Horns in G4LBNF 15

Impact on the Near to Far ratio.

This is the ratio of ratios previously shown, Near over Far. Virtually no impact if B → Ideal to Real. (Good news!)

December 15/23 2016 Realistic Horns in G4LBNF 16

Next Steps...

✔

Implement Horn C Revision 2. (Team Center #10071767) Same methodology as before..

✔

Do we need to retune a bit, if the shape of the focusing tail peak matters? By this, I mean moving Horn B with respect to Horn A, (easy), or reducing the length of the IC by a few percent? (need to redo the FEA analysis.... Probably not ?

✔

Study the field maps, and corrections due to horn deformations, I/O transition regions, etc.. (Colorado, UTA & IIT )

✔

??