HP 5061 Cesium Resonance

• HP 3325A frequency synthesizer
• HP 3456A digital voltmeter
• HP 5061A cesium beam frequency standard
• The 3325A generates the 12.x MHz signal
• The 5061A generates the 9180 MHz signal
• A 5 MHz house standard drive both the above
• 12.x MHz injected into 5061A harmonic generator A4 J2
• 5 MHz reference injected into 5061A 90 MHz multiplier A3 J5
• Beam current measured across meter M1 in "Beam I" position
• 5061A operated in open loop mode with modulation off
• A QBASIC program drove the 3325A and the 3456A over GPIB
• The 12.x MHz synthesizer was stepped 10 Hz per sample
• Sample rate was 2 or 3 samples per second
• Data collected for 12.450 MHz to 12.800 MHz
• 35,001 data points raw data (630 k bytes)
• Plots generated with Excel

500 kHz wide plot of the entire scan showing all seven resonances:

Zoom in 10x for a view of the middle peak only:

Zoom in another 10x for a closer look:

Zoom in another 10x and see just the 9192.631770 MHz center peak:
FWHM is 550 Hz giving a resonator Q of 17 million.

Final 50x zoom (10x vertical 5x horizontal) to see the very top of the peak:

Lab photos.

A four foot long chart recorder version of the seven resonances. Click on link and scroll down with your browser.

Lastly, a view of each of the seven peaks.

New data from Monday night (12-Mar-2001).

• 10 kHz wide scan
• 1 Hz resolution
• DVM set for 100 PLC (power line cycles) to remove measurement noise
• Sample rate was about 1.5 seconds per point
• It ran overnight
• 10,001 data points raw data (190 k bytes)

10x zoom

50x zoom

5x zoom