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LEPTA project

Measuring lifetime of positronsLaboratory of nuclear problems

Supervisor: S.Yakovenko

JINR, Dubna

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Goals of the LEPTA project

• Dynamics of coupling motion in the stellatron

• Electron cooling of positrons

• Positronium generation in flight

• Positronium physics

• Electron cooling with circulating electron beam

• Feasibility study of antihydrogen generation in flight

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septum

kicker

cooling section

positronium detector

positron trap

Design of the LEPTA

22Na106 e+ per sec

10 6100sec=10 8 e +

10 4 Ps per sec

e-gun

collector

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General parameters of the ringCircumference , m 17.2

Particle energy, keV 1 - 10

Longitudinal magnetic field, G 300 - 1000

Radius of the toroidal solenoids, m 1.45

Helical quadrupole gradient, G/cm 0 - 20

Length of the helical quadrupole, m and number of steps of the helix

1.62

Number of positrons in the ring 1*108

Residual gas pressure, Тоrr 1*10-10

Design of positronium beam parameters

Intensity, atom/s 110

Angular spread, mrad 1

Velocity spread 1104

Beam diameter at the exit of the ring, cm 1.1

Positronium decay length, m 8.52

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Beam diagnostic tools and correction coils disposition

Horizontal PU

kicker

Helical quadrupole

Electron gun

Vertical PU

DL

D = 79 mm, L = 126 mm

Vertical PU

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Beam lifetime

10 µs

“Killer” pulse wasapplied to the kicker plate

signal from PU

y = 74,962e-0,1728x

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10

100

0 2 4 6 8 10 12

time, msec

U,

mV

Our results:

Lifetime: 5,787037 ms