| Checking SQUET ZC-23 |
| | In the last run we used ZC-23 on DIB3, whose only connected channel is DIB3pC which connects to Side1pA. This SQUET should have all of its shunt resistances reduced by 1/3 by wirebonding the 10 mΩ resistor in parallel with the 20 mΩ. But IbIs measurements suggested that the shunt resistance was the standard 20 mΩ. So we'll take a look and see whether the wirebond is there or not. |
| 1330 | Measure the QET to QET Return resistances on the stripline side. Remembered that in the past the shunt-reducing wirebonds made measurable differences in these resistances at room temperature. Found the following: pA/B/C/D = 12/21/20/12 Ω. So maybe pA and pD are reduced but pB and pC are not. |
| 1345 | Removed the protective cover from the SQUID card, and accidentally touched the pC bonds, damaging most of them. So it will certainly need to be rebonded. |
| 1445 | Finish rewirebonding. Redid all the damaged bonds on pC. It did indeed look like the extra bonds on pB and pC to reduce the shunts had come loose on the copper side. Maybe the bonds were too short and the thermal cycle broke them. Also the copper had not been scraped to make a shiny spot when I did the original bonds - I scraped it this time. Redid the shunt-reducing bonds on both pB and pC. |
| 1500 | Reassemble SQUET and remeasure QET to QET returns: all around 12 Ω now, good. |
| 1510 | Check the other phonon-related resistances - except for pA (known problems - open SQUID) all look good. |