1. Effect of the Solenoid Field on the Luminosity Monitor
The XXX PANDA meeting
Sep.7-11,2009, Juelich
Effect of the Solenoid Field on the Luminosity Monitor
Huagen Xu
IKP: T. Randriamalala, J. Ritman and T. Stockmanns
15 September, September, 2018

2. Outline One Tentative Geometry of LuMo
Effect of the Solenoid Field on LuMo
Confirmed Results
Summary 2

3. 1. One Tentative Geometry
16 Silicon sensors with trapezoidal shape on 4 planes;
Distance between neighbouring planes: 20cm.
Dimension: 2 cm(short side)X5 cm(height)X5.33 cm(long side);
Thickness : 150 μm;
Single/Double side stripped; 3

4. Digi & Reco Reco Hits Plot Strip on Front/Back Side, pitch = 50 μm
FrontSide
BackSide 4
Reco Hits Plot

5. Spatial Resolution
σ = 10 μm/30 μm
52.7 μm
σ = 30 μm/10 μm
158.2 μm 5

6. Track Theta RecoHitsTheta : Theta by fitting RecoHits ,
Beam axis θ
Hits
RecoHitsTheta : Theta by fitting RecoHits ,
MCHitsTheta : Theta by fitting MCHits,
MCtrue Theta : Theta of particle’s mother track 6

7. RecoHitsTheta - MCTruetheta MCHitsTheta - MCTruetheta
Theta resolution
RecoHitsTheta - MCTruetheta
MCHitsTheta - MCTruetheta 7

8. 2. Effect of the Solenoid Field
Field on
Field off
RecoHitsTheta Resolution vs
Beam Momentum
for antiproton
Difference 8

9. Peak of MCHits Theta RMS of MCHits Theta Field On Field Off On - Off 9
Field On
Field Off
On - Off

10. Field Map plotted one map file map file1+2+3+410

11. MCHits’ plot with field and with no field
Field On
Field Off
MCHits’ plot with field and with no field
BoxGenerator;
Beam Particle: antiProton;
Beam momentum: 1.5GeV/c;
Fixed theta: 5mrad;
Azimuth: 0~360;
Give rise to ~0.5 mrad shift toward beam axis for antiProton. 11

12. 3. Confirmed Information
Reason: due to the rectangular aperture of downstream door for solenoid, the Y-field is much higher than X-field.
Figure from Jost Lühning 12

13. Track of Proton from IP Emitted from IP with 1.5GeV/c and 5mrad
Figure from Jost Lühning 13

14. Track of Proton and antiProton from IP
Emitted from IP
with 1.5GeV/c
and 5mrad
Proton: red
antiProton: blue
Figure from Jost Lühning 14

15. Geane prediction (forward mode)
Start plane: IP plane;
Start position: IP position(0,0,0);
(antiProton with 1.5GeV/c and 5mrad) 15

16. (Geane – MC)/ (Geane Propagation Error)
Pull distribution
(Geane – MC)/ (Geane Propagation Error) 16
Geane Hits
fit theta
MCHits theta

17. Geane prediction (Backward)
Start plane: the first detector plane;
Start position: the MC Hits of antiProton on the first detector plane;

18. Position and Theta (Backward)
fX, fY at IP
Theta = 5.022mrad

19. 4. Summary
With a new tentative geometry of LuMo the effect of the Solenoid field was found, for antiProton with momentum of 1.5GeV/c the theta of track would be shifted ≈ LuMo ;
The effect was confirmed by Solenoid experts;
The effect was convinced by using Geane packages with forward and backward mode as well. 19

20. Thanks for your attention!20