Difference between revisions of "BEC preparation"
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There are 28 steps in electronics while the ultracold atomic cloud is prepared. | There are 28 steps in electronics while the ultracold atomic cloud is prepared. | ||
# MOT preparation | # MOT preparation | ||
| + | ==Cooling and repumping== | ||
==Magnetic coils== | ==Magnetic coils== | ||
| − | Inductance 40 mH | + | Inductance 40 mH, How the switch on time is different from switch off, why it moves during one process? |
| + | ===January 2020=== | ||
| + | Measurement with a network analyzer and the test coil: | ||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! Resonant freq. [kHz] !! Capacitance [nF] !! Li [mH] !!Conditions | ||
| + | |- | ||
| + | | 1510 || 0 || || Only the coil | ||
| + | |- | ||
| + | | 718.25 || 0.47 || 3.9 || | ||
| + | |- | ||
| + | | 520 || 1 || 3.25 || 102 | ||
| + | |- | ||
| + | | 371 || 2.2 || 3.1 || | ||
| + | |- | ||
| + | | 173.75 || 10 || 3.27 || 103 | ||
| + | |} | ||
| + | Measurement with a network analyzer and experimental coils connected in series, measured near MOSFETs: | ||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! Resonant freq. [kHz] !! Capacitance [nF] !! Li [mH] !!Conditions | ||
| + | |- | ||
| + | | 391 || 0 || || Only the coil | ||
| + | |- | ||
| + | | 317 || 0.47 || 7.2 || | ||
| + | |} | ||
| + | <math> \omega_0 =1/\sqrt{L C_0}</math> | ||
| + | |||
| + | <math> L C_0 =1/\omega_0^2</math> | ||
| + | |||
| + | <math> L_i = (1/\omega_i^2-1/\omega_0^2)/C_i</math> | ||
| + | ==Switching times== | ||
| + | There are 24 MOSFETs (BZW50-47L) connected in parallel, we connect a TSV diode for each raw (IXN 180N25T). 420 A and 7 mH results in 617 J of energy stored. The peak voltage 2.9 kV is generated if we make the switching 1ms. In Spielman's group they claim to achieve a few us switching time (p 74. Garcia's thesis). Another option is to follow the technique proposed in Toronto. | ||
[[Category:BEC]] | [[Category:BEC]] | ||
Latest revision as of 13:25, 23 July 2020
There are 28 steps in electronics while the ultracold atomic cloud is prepared.
- MOT preparation
Cooling and repumping
Magnetic coils
Inductance 40 mH, How the switch on time is different from switch off, why it moves during one process?
January 2020
Measurement with a network analyzer and the test coil:
| Resonant freq. [kHz] | Capacitance [nF] | Li [mH] | Conditions |
|---|---|---|---|
| 1510 | 0 | Only the coil | |
| 718.25 | 0.47 | 3.9 | |
| 520 | 1 | 3.25 | 102 |
| 371 | 2.2 | 3.1 | |
| 173.75 | 10 | 3.27 | 103 |
Measurement with a network analyzer and experimental coils connected in series, measured near MOSFETs:
| Resonant freq. [kHz] | Capacitance [nF] | Li [mH] | Conditions |
|---|---|---|---|
| 391 | 0 | Only the coil | |
| 317 | 0.47 | 7.2 |
Switching times
There are 24 MOSFETs (BZW50-47L) connected in parallel, we connect a TSV diode for each raw (IXN 180N25T). 420 A and 7 mH results in 617 J of energy stored. The peak voltage 2.9 kV is generated if we make the switching 1ms. In Spielman's group they claim to achieve a few us switching time (p 74. Garcia's thesis). Another option is to follow the technique proposed in Toronto.
