Run 25

For this run we've taken some PSDs and noise data (~500 events) for various configurations with the DCRC boards and flexible/rigid side coaxes.

The flexible side coax for this run used the new SCAB board, which used surface mounted devices rather than wirebonded devices. The SCAB and assembled flexible side coax are pictured below.

Figure 1: Finished Flexible Side Coax v2 SCAB (left) and Unsoldered Flexible Side Coax v2 SCAB (right)
Larger image: 3968 x 2232
Figure 2: Assembled Flexible Side Coax v2.

For a description of the procedure, see Run 24's Run Summary: Run 24 Setup Description

• Took data for DCRC32 attached to the flexible side coax and DCRC33 attached to the vacuum side coax. We took PSD data at rest (without inducing microphonics) and after dropping a weight onto the fridge frame (this is the same weight used in Run 24 but wrapped in some clean room wipes this time).
• Boards were swapped and the drop test was performed again showing no noticeable difference.
• Connected both coaxes to DCRC32 while DCRC33 was off so as to eliminate interference from the other DCRC's power supply. Data was taken at rest and we did a mass drop test.
• Connected both coaxes to DCRC33 took data at rest, did a mass drop test, and hit the fridge with a mallet.

The following day At Rest, 20cm Drop Test, and Hitting Frame PSD data (trace length of 26.2144ms) was taken for the four following configurations:

• DCRC32 attached to Flexible Side Coax; DCRC33 attached to Vacuum Side Coax.
• DCRC33 attached to Flexible Side Coax; DCRC32 attached to Vacuum Side Coax.
• DCRC32 attached to both Side Coaxes; DCRC33 turned off.(To prevent interference between power supplies).
• DCRC33 attached to both Side Coaxes; DCRC32 turned off.(To prevent interference between power supplies).

Data was taken on 2012/03/21, 2012/03/22, and 2012/03/23. PSD data collected on these days can be found on their respective run diary pages. Note that after the first day of taking data, the fridge-side lights were turned off to clean up the PSDs.

• 2012/03/21 - only PSD data was taken (lights on)
• 2012/03/22 - PSD data was taken at rest, dropping a mass, and hitting the frame. Noise data (~ 500 events) was taken at rest and while hitting the frame. The trace length for the PSDs on this day were 10 ms.
• 2012/03/23 - PSD data was taken for the same configuration as March 22nd. Noise data was taken at rest and while dropping a mass.

Some notes on data taking and inducing microphonics:

• When hitting the fridge frame with the mallet, tower temperature increased noticeably.
• Qo on both side-coaxes exhibited noisy sinusoidal behavior that got worse when walking/working around the fridge. It seemed very sensitive. For example, if the condenser line was lifted (perhaps it was touching the ebox), Qo's noise would sharpen dramatically, and then die back down.
• We attempted to use the installed piezo speaker to induce microphonics but there was no noticeable effect. Only 500 mV were applied to the speaker, so for the next run we'll increase this output to ~ 10 Vpp. We also put normal table top speakers on top of the fridge but there was still no noticeable effect. Picture of "detector" with piezo speaker installed

Conclusion

• The PSDs from the vacuum and flexible side coaxes were found to be comparable.
• Qo of the Flexible Side Coax was consistently slightly noisier near 1.5kHz than Qo of the Vacuum Side Coax. However, Qi on the Flexible Coax remains similar to Qi on the Vacuum Coax.
• Figure 3 shows plots typical of the data set. The rest of the PSD data can be found at: Charge Noise PSDs
• Pulses have been acquired for all the tests described above for further analysis offline if deemed necessary. Noise data was also acquired for each board configuration at rest and with the 20 cm drop test. This list of data can be found here: 2012/03/23 Noise Data Taken

• Run 26 will test Flexible Side Coax v_2, which includes the updated SCAB and SCHUBA boards:
• Updated SCAB and SCHUBA Boards