Experiments with Supersonic Beams as a Source of Cold Atoms

MCP Signal [arb. units]
2.0
1.5
(1)
1.0
(2)
0.5
(3)
0.0
2.0 2.5 3.0 3.5 4.0 4.5 5.0
Time of flight [ms]
Figure 4.31: Time of flight profiles where a variable phase is used in the coilgun All
three coils have the same predicted final velocity, 136 m/s. The phases used are,
(1) φi =32.9 ◦ and a cutoff phase φf =53.6 ◦ which is reached after 20 coils, and a
measured velocity vf = 130 m/s, (2) φi =38.6 ◦ and a cutoff phase φf =46.3 ◦ reached
after 47 coils with vf 136m/s, and (3) has constant phase φ =44.3 ◦ and 132m/s final
velocity. The slow peak of (1) has increased flux by a factor of 1.18 over (2) and a
factor of 1.85 over (3). The noise that appears on and around the unslowed portion
of the beam is electronic noise due to the pulsing of the coils. This data was taken
before the coil electronics was optimized, which is why the phases are higher than for
the data described in figure 4.30 and table 4.2.
108