Geant 4 Detector Simulation

05/02/23 Chun-Min Jen, Summer 09, May Syracuse Uni.

1

Uniform B-field

5 m

Supposed that “Everything” is composed of “Vacuum” …

1.5 m

detector # : 0 1 2 3 4 5 6 7

Chun-Min Jen, Summer 09, May Syracuse Uni.

205/02/23

Sample: Signal Criteria

Generate 6’000 & 60’000 events Etotal = 3 GeV – 7 GeV incident = 25º - 35º All e- (negatively charged, light particle) No interactions w/ any matter, for example,

the tracking chambers, medium and the target (point source).

Single hit per tracking chamber / detector “Purely” helix motion in an uniform B-field


305/02/23

X’ (t)

Y’ (t)

Uniform B-field : Summary X (t) = a*cos(t+)-a*cosY (t) = a*sin(t+)-a*sinX (t) = C*cos*t

X (t) = a*cos(t)-aY (t) = a*sin(t) X (t) = -0.5*a*2*t2Y (t) = a**t X = X7-X4 = -0.5*a*2*(t7

2 – t42) ; X/t = -0.5*a*2*(t7

+ t4) ; X = (X/t)*t + X -(X/t)*t = 0.5*a*2*t7*t4 = 0.5*(C*P┴/e*B)*(e*B/P)2*(Z7*Z4/C2*cos2) ~ sin/ P*cos2tanrec ~ (Y7 - Y4)/(Z7 - Z4) = tanini

=X (t)

Y (t)

cossin

-sincos

Rotation Transformation

Physics Invariance = 0

t << 1 /

S1S2 Z

B = 1.5 T ( )Y

X


405/02/23

3 GeV 25º 30º 35ºT (period) (sec) 1.40e-7R (m) 2.82 3.33 3.82 Z (per T) (m) 38.05 36.36 34.39 5 GeVT (period) (sec) 2.33e-7 R (m) 4.70 5.56 6.37 Z (per T) (m) 63.42 60.60 57.32 7 GeVT (period) (sec) 3.27e-7 R (m) 6.57 7.78 8.92 Z (per T) (m) 88.78 84.84 80.25


605/02/23

/ (sin / P*cos2Based on P.3

/ (/ P)Based on P.7

v.s. P

v.s. P

v.s. ini v.s. ini


705/02/23

/ (/ P)Based on P.7

/ (sin / P*cos2Based on P.3K2 ~ 14 – 15

P (rec, )= K2*sinrec / *cos2rec

ini (rec, ) = rec

K1 / Pini

= 0.017

K1 ~ too small

K1 / ini

= 0.045

K1 abandoned!

K2 / Pini

= 14.1

K2 is more reliable

and stable!

K2 / ini

= 15.3


805/02/23

S

S1 / Pini

= 9.13 S1 / ini

= 15.3

S v.s. Pini S v.s. ini


905/02/23

(S1 / ) / Pini

= 0.05(S1 / ) is reliable!

(S1 / ) / ini0.009

= 0.05

/ (sin / P*cos2Based on P.3K2 ~ 14 – 15

P (rec, )= K2*sinrec / *cos2rec

ini (rec, ) = rec

(S1 / ) = 0.05S1 (P, ini) = 0.05*= 0.05* K2*sinrec / P*cos2rec

S / v.s. PiniS / v.s. ini

S /


1005/02/23

To-Do List :

Figure out the problem which caused X and Y not equal to zero. (in P.5 – P.6)

Apply a non-uniform B-field and as realistic materials as what the proposal described to our G4 simulation.

Compare the outcome with that derived from the uniform B-field case. See how much it may change with the impact of a non-uniform B-field as well as interactions between negatively charged electrons and materials on G4 simulation.

Proceed to the multi-hit case. More sophisticated. Need more time Programming…

Geant 4 Detector Simulation

Technology

Transcript of Geant 4 Detector Simulation