Towards (anti)hydrogen production Am elia Leite SPP/Irfu, Cea - - PowerPoint PPT Presentation

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Towards (anti)hydrogen production Am elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion Outline Motivation for GBAR

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Towards (anti)hydrogen production

Am´ elia Leite

SPP/Irfu, Cea Saclay

PHENIICS Doctoral School Days

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Outline

◮ Motivation for GBAR ◮ GBAR in 3 steps ◮ How do we produce (anti)hydrogen? ◮ Positron production and accumulation ◮ Positronium ◮ Proton source ◮ Conclusion

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 2

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Motivation

Weak Equivalence Principle is a cornerstone of relativity ↓ Never been tested with Antimatter ↓ Absence of primordial antimatter in the observable Universe → Different behaviour of antimatter under gravity? ⇓ GBAR: Gravitational Behaviour of Antihydrogen at Rest ↓ ¯ g measurement

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 3

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR: Gravitational Behaviour of Antihydrogen at Rest

Measure the acceleration of ¯ H in free fall

inertial mass of H free fall time gravitational mass of H free fall height gravitational acceleration initial vertical velocity

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 4

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR: Gravitational Behaviour of Antihydrogen at Rest

Measure the acceleration of ¯ H in free fall

inertial mass of H free fall time gravitational mass of H free fall height gravitational acceleration initial vertical velocity

Original idea: Use ¯ H+ ions to achieve µK temperature (0.1 m/s) by sym- pathetic cooling → e+ photodetachment → ¯ H free fall

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 5

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR in 3 steps

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR in 3 steps

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR in 3 steps

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 8

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR @ Saclay

e- linac 4.3 MeV W target+ moderator e-/e+ magnetic separator slow e+ beam line 3x106 e+/s

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 9

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Cross section measurements

1. Hydrogen and negative hydrogen ion production

p + Ps → H + e+ @Cea H + Ps → H− + e+ @Cern

e- e+ Ps

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 10

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Cross section measurements

1. Hydrogen and negative hydrogen ion production

p + Ps → H + e+ @Cea H + Ps → H− + e+ @Cern

e- e+ Ps

2. Antihydrogen and antihydrogen ion production

¯ p + Ps → ¯ H + e− @Cern ¯ H + Ps → ¯ H+ + e− @Cern

p e+ e+

H

+

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 11

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positron accumulation

Buffer gas trap Charged particles can be stored in a Penning trap ad eter- num (if your trap is good enough!) Yet the e+ need to loose enough energy → use a buffer gas for inelastic collisions: e+

8−11eV + N2 → e+ + N∗ 2

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 12

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positron accumulation

Buffer gas trap Charged particles can be stored in a Penning trap ad eter- num (if your trap is good enough!) Yet the e+ need to loose enough energy → use a buffer gas for inelastic collisions: e+

8−11eV + N2 → e+ + N∗ 2

Penning-Malmberg trap Store e+ bunches and form a plasma with 1010 e+

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 13

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Buffer gas trap

Two stage trap with a third stage accumulator Efficiency ∼ 20% to 30%

Cooling with CO2 or SF6 To Penning

Malmberg trap

50 eV e+ Trapping with N2 pumping

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 14

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Buffer gas trap

We are slowly building the trap from scratch...

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 15

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Buffer gas trap

Now it looks better but it’s not ready yet!

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 16

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Penning-Malmberg trap

Superconducting magnet: 5T → radial confinement

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 17

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Penning-Malmberg trap

27 annular electrodes: electrostatic field → longitudinal confinement

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 18

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Penning-Malmberg trap

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Accumulation technique

e+ injection → e+ confinement + stacking → e+ ejection

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 20

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Accumulation technique

e+ injection → e+ confinement + stacking → e+ ejection

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 21

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positronium production

Ortho-positronium, τ=142ns Para-positronium, τ=125ps e+ Mesoporous film, SiO2

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Proton source

Quadrupole Proton gun Steering & focussing Dri tube for TOF Faraday cup

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 23

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Reaction scheme

p Microchannel plate detector & Phosphor screen e+ H- Faraday cup Mesoporous film, SiO2 Ps Camera Si3N4 membrane H Electrostatic quadrupole p Camera Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 24

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Conclusion

◮ Setup assembly in progress ◮ Commission during summer ◮ Stay tuned for hydrogen production next fall!

Thank you!

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 25

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Questions?

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Extra Slides

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

GBAR vs AEGIS

GOAL: ∆g

g ≤ 1%

GBAR: cooled ¯ H+ → slow ¯ H L = 0.1 m and v ¯

H = 0.5 m/s ⇒ 20 cm

(T ¯

H ∼ 10 µK ∼ 7neV )

AEGIS: ¯ H beam L = 1 m and v ¯

H = 500 m/s ⇒ 20 µm

(T ¯

H ∼ 100 mK ∼ 7 µeV )

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 28

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Equivalence principle

“The trajectory of a point mass in a gravitational field depends

nly on its initial position and velocity, and is independent of

its composition and structure.”

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 29

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Buffer gas trap

10 mm orifice? 45 mm 391 mm 939 mm 1117 mm 1819 mm 2475 mm 0 mm 20 A 10 A 10 A 10 A 200 A H2 H2 H2 H2 H1 218 mm 1291 mm 2063 mm 2658 mm

B = 0.1 mT Turbo Cryo

685 mm 2295 mm 2823 mm 1481 mm

271 mm
366 mm
176 mm

H2 90 A

5T 1T

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 30

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positronium production

Mesoporous film

◮ pure silica (SiO2) with nanometer size pores ◮ emits orho-positronium (∼10 meV) upon

implantation of e+ (∼keV)

◮ high (∼30%) efficiency

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 31

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positronium production

Mesoporous film

◮ pure silica (SiO2) with nanometer size pores ◮ emits orho-positronium (∼10 meV) upon

implantation of e+ (∼keV)

◮ high (∼30%) efficiency

Ps cloud density: @Cea: 1010 Ps/cm3 @Cern: 1012 Ps/cm3

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 32

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positronium production & spectroscopy

Spectroscopy Detection of the fluorescence light: 3D to 2P transition → infra-red photon at 1312nm 2P to 1S transition → UV photon at 243nm

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 33

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Positronium production & spectroscopy

Spectroscopy Detection of the fluorescence light: 3D to 2P transition → infra-red photon at 1312nm 2P to 1S transition → UV photon at 243nm Detectors: Annihilation → scintillators Fluorescence → optical fibers + photomultipliers

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 34

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Hydrogen detection

Background sources

◮ Gamma radiaton from e+ and Ps annihilation ◮ MCP noise ◮ Charged particles - separated by TOF

Am´ elia Leite SPP/Irfu, Cea Saclay PHENIICS Doctoral School Days 35

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Motivation GBAR in 3 steps Cross section measurements Positron accumulation Proton source Conclusion

Cross section measurements

Only one previous study on p + Ps → H + e+ for p energies 11.3, 13.3 and 15.8 keV with a total of 211 events Merrison et al, Phys. Rev. Letters 78,2728 (1997)

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