BE-ABP-HSC Non convex chamber in PyECLOUD Electron Cloud meeting 27-05-15 G. Iadarola, A. Romano, G....

BE-ABP-HSC

Non convex chamber inPyECLOUD

Electron Cloud meeting 27-05-15

G. Iadarola, A. Romano, G. Rumolo

BE-ABP-HSC



PS standard Chamber

LHC standard Chamber

SPS Drift A Chamber

R = 78

mm

BE-ABP-HSC



PS standard Chamber

LHC standard Chamber

SPS Drift A Chamber

R = 78

mm

Non convex Polygon

BE-ABP-HSC



The chamber module in PyECLOUD The function “IsOutside”

checks if a point (x,y) is internal or external to the chamber. P lies outside the polygon if for at least one edge is verified:

The function “ImpactPointAndNormal”, computes the crossing point between the segment Pin Pout and the chamber’s profile

These algorithms work for convex polygon !

BE-ABP-HSC Electron Cloud meeting 27-05-15

The “IsOutside” function 1/3

Convex Chamber Non-Convex Chamber


The “IsOutside” function 2/3Point-In-Polygon algorithm One simple way of finding if

a test-point is inside or outside a general polygon

The number of intersections for a ray, starting from the point and going in any fixed direction, says where is the point :

o If it is ODD, the point lies inside

o If it is EVEN, the point lies outside


The “IsOutside” function 3/3

Convex Chamber No-Convex Chamber


The “ImpactPointAndNormal” function 1/3



The “ImpactPointAndNormal” function 2/3 If the polygon is not convex,

we can have more crossing point between the segment Pin Pout and the chamber’s profile

The minimum value of the crossing point for a same segment shoud be taken

Pout

Pin



The “ImpactPointAndNormal” function 3/3


Convex/nonconvex switch

convex polygon

The specific algorithm can be applied !

if the sign of all the cross

products is the same

For each set of three adjacent

point A,B,C find the cross

product AB x BC

Algorithm to detect the type of polygon


Convex/noconvex switch

no-convex polygon

Algorithm to detect the type of polygon

For each set of three adjacent

point A,B,C find the cross

product AB x BC

if the sign of all the cross

products is the same

13

Electric Field X

Electric Field Y

PyPIC 1.02 : R

efined interpolation


Electric Field X

Electric Field Y

PyPI

C 1

.01:

Ext

rapo

latio

n m

etho

d

Document reference 14

Model of the LHC beam screen

The aim is to study the EC build up through the holes of the

LHC beam screen with and without baffle plates BE-ABP-HSC Electron Cloud meeting 27-

05-15

Document reference 15BE-ABP-HSC Electron Cloud meeting 27-05-15

Document reference 16

Conclusion and Next Steps Implementation in PyECLOUD of non-convex

chamber geometries

Improvement of the code in order to correctly manage :

o detection of in/out particles with respect to the chamber

o impact of particles against the chamber wallo Interpolation of the electric field near the boundaries

Simulations on EC build up will be carried out in order to quantify the EC threshold and the Heat Load with and without baffle platesBE-ABP-HSC Electron Cloud meeting 27-

05-15

BE-ABP-HSC

Thanks for your attention!


BE-ABP-HSC Non convex chamber in PyECLOUD Electron Cloud meeting 27-05-15 G. Iadarola, A. Romano, G....

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