The Shape and Development of an Electromagnetic Shower a BL4S EXPERIMENT the Particle Peers

The shape and development of an electromagnetic shower A BL4S EXPERIMENT The Particle Peers

Cecile Wiersema Isabelle Koster Abracha Koens Ilja de Goede Frederiek de Bruine Janiek Weening

Our proposal video: https://www.youtube.com/watch?v=va1ZnjllFDk

30-01-2020 A BL4S EXPERIMENT 2 Research question

Is there a difference in the shape and development of a positron-intitiated electromagnetic shower and an electron-intitiated electromagnetic shower?

30-01-2020 A BL4S EXPERIMENT 3 Electromagnetic (EM) particle shower

- Processes: pair production & bremsstrahlung - Shower radius as a property to compare e+ and e-

30-01-2020 A BL4S EXPERIMENT 4 Set-up - Performed in the DESY II Test Beam Facility - Beam telescope with 3x2 cm silicon sensors

30-01-2020 A BL4S EXPERIMENT 5 Set-up - Absorbers ◦ Tungsten: 2mm, 4mm, 9mm, 14mm; ◦ Copper: 20mm; - Energies ◦ 0.5 GeV, 1-6 Gev

- Annihilation may cause a difference

30-01-2020 A BL4S EXPERIMENT 6 Cuts to increase reliability

- We made cuts to the position of the first plane to ignore the edge particles

30-01-2020 A BL4S EXPERIMENT 7 Two-dimensional shower shape

30-01-2020 A BL4S EXPERIMENT 8 Shower radius

90% quantile

30-01-2020 A BL4S EXPERIMENT 9 Shower radius in mm

positrons electrons 1 GeV 3 GeV 5 GeV 1 GeV 3 GeV 5 GeV 2 mm 9.6 8.8 8.5 2 mm 9.6 8.8 8.5 4 mm 10.3 9.8 9.6 4 mm 10.3 9.9 9.7 Tungsten 9 mm 10.3 10.1 10.0 9 mm 10.3 10.1 10.0 14 mm 9.9 9.8 9.9 14 mm 9.9 9.8 9.9 Copper 20 mm 9.3 8.9 8.9 20 mm 9.2 8.9 8.9

30-01-2020 A BL4S EXPERIMENT 10 Shower radius in mm

Positron vs. electron

30-01-2020 A BL4S EXPERIMENT 11 Shower radius in mm

If the energy increases, the shower radius decreases

30-01-2020 A BL4S EXPERIMENT 12 Shower radius in mm

The absorber thickness influences the shower radius

30-01-2020 A BL4S EXPERIMENT 13 Shower radius in mm

According to the similar radiation length, the 9 mm tungsten and the 20 mm copper should have a similar shower radius

30-01-2020 A BL4S EXPERIMENT 14 Longitudinal development absorber thickness

30-01-2020 A BL4S EXPERIMENT 15 Longitudinal development different energies

30-01-2020 A BL4S EXPERIMENT 16 Longitudinal development particle type

30-01-2020 A BL4S EXPERIMENT 17 Comparing the number of clusters

6 GeV, 4 mm, positrons/electrons 102%

102%

101%

100%

99%

98%

97% 0 1 2 3 4 5 neg. uncertainty measured pos. uncetainty 100%

30-01-2020 A BL4S EXPERIMENT 18 Comparing the number of clusters

6 GeV, copper, positrons/electrons

103%

102%

101%

100%

99%

98%

97%

96%

95% 0 1 2 3 4 5 neg. uncertainty measured pos. uncertainty 100%

30-01-2020 A BL4S EXPERIMENT 19 Comparing the number of clusters

6 GeV, copper, positrons/electrons

103%

102%

101%

100%

99%

98%

97%

96%

95% 0 1 2 3 4 5 neg. uncertainty measured pos. uncertainty 100%

30-01-2020 A BL4S EXPERIMENT 20 Discussion - Scattering - Magnet deviations - 0.5 GeV - Antimatter as absorber

30-01-2020 A BL4S EXPERIMENT 21 Future - Fitting - Influence magnet deviations - Simulations

30-01-2020 A BL4S EXPERIMENT 22 Questions Contact us via: [email protected]

30-01-2020 A BL4S EXPERIMENT 23 Back - Up

30-01-2020 A BL4S EXPERIMENT 24 30-01-2020 A BL4S EXPERIMENT 25 Uncertainty

1 1 1 1 휎 = + + + 푛푝,푖 푛푝,0 푛푒,푖 푛푒,0

where for positrons 푛푝,푖 is the number of clusters in plane i, 푛푝,0 the number of clusters in plane 0, and 푛푒,푖 and 푛푒,0 the same for electrons.

30-01-2020 A BL4S EXPERIMENT 26