2022/12/28 (Wednesday)
- Lab in-personnel: Matt
| Status | Run 76 finished |
|---|---|
| Setup | DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) |
| IVC closed and Turbo pumping for a few days. No tower - this is just a leak test. | |
| 1115 | Perform Tower electrical check, to see if resistances look different compared to before the Run76 installation (compare with 2022 March 9) . This is to look for clues about the extra HV leakage we saw after the HV mishap during Run 76. |
| Run 76 Tower Electrical Checkout, Pre and Post | ||||
|---|---|---|---|---|
| Device | Label | Unit | Pre R76 Value | Post R76 Value |
| Face5pA | Side1pE | Ω | 337.1 | 326.9 |
| Face5pB | Side1pB | Ω | 140.8 | 140.4 |
| Face5pC | Side1pD | Ω | 418.4 | 405.4 |
| Face5pD | Side2pE | Ω | 321.7 | 319.1 |
| Face5pA-pB | same side inter | kΩ | 1.375 | 0.497 |
| Face5pA-pC | same side inter | kΩ | 1.876 | 0.697 |
| Face5pA-pD | opp side inter | kΩ | 2.709 | 2.145 |
| Face5pB-pC | same side inter | kΩ | 1.328 | 0.431 |
| Face5pB-pD | opp side inter | kΩ | 2.225 | 1.951 |
| Face5pC-pD | opp side inter | kΩ | 2.612 | 1.903 |
| Face5LED1 | pin-to-chassis | V | 1.067 | 1.067 |
| Face5LED2 | pin-to-chassis | V | 1.01 | 0.863 |
| Face3pA | Side2pC | Ω | 377.1 | 376 |
| Face3pB | Side2pF | Ω | 516.9 | 515.2 |
| Face3pC | Side1pC | Ω | 438.7 | 438.9 |
| Face3pD | Side1pF | Ω | 440.6 | 406.5 |
| Face3pA-pB | same side inter | kΩ | 1.848 | 0.376 |
| Face3pA-pC | opp side inter | kΩ | 2.813 | 2.618 |
| Face3pA-pD | opp side inter | kΩ | 2.776 | 2.203 |
| Face3pB-pC | opp side inter | kΩ | 2.906 | 2.707 |
| Face3pB-pD | opp side inter | kΩ | 2.803 | 2.276 |
| Face3pC-pD | same side inter | kΩ | 1.936 | 1.084 |
| Face2pA | Side2pB | Ω | 140.8 | 140.5 |
| Face2pB | Side2pA | Ω | 87.1 | 87 |
| Face2pC | Side1pA | Ω | 101.1 | 100.9 |
| Face2pD | Side2pD | Ω | 389.7 | 386.9 |
| Face2pA-pB | same side inter | kΩ | 0.774 | 0.765 |
| Face2pA-pC | opp side inter | kΩ | 1.992 | 1.628 |
| Face2pA-pD | same side inter | kΩ | 1.347 | 1.321 |
| Face2pB-pC | opp side inter | kΩ | 2.121 | 1.766 |
| Face2pB-pD | same side inter | kΩ | 1.644 | 1.524 |
| Face2pC-pD | opp side inter | kΩ | 2.395 | 1.902 |
Observations:
- All resistances are at least a little lower now than at the beginning of R76
- The biggest changes are in same-side interchannel resistances.
- The biggest drop is Side 2 C-F, which fell by 80%
- Side 1 E-B, E-D, B-D all fell by more than 60%
- Side 2 A-B, B-D barely changed, falling less than 2%
- Also big drops in opposite-side interchannel resistances.
- Drops range between 7% and 21%
- Changes in resistances of channels themselves are small
- most less than 1%
- highest drop is Side1pF, 8%
- Considering that the HV mishap applied high bias to Side 1, you might expect Side 2 to be less affected
- Only one Side2 interchannel resistance was strongly affected: Side2 C-F. The others we looked at changed by less than 8%
- All the Side1 interchannel resistances were strongly affected, falling by 44% to 68%
- Note that Face2 is the only case where we are measuring between some channels on different DIBs
- The same-side interchannel resistances measured between different DIBs show the smallest changes
- suggests that maybe some of the damage is in the DIBs, or in the bond-pad region near the DIBs
Table below shows which SQUET channels showed damage when we measured at the breakout box at 13 K:
| Cable | SQUET | problems |
|---|---|---|
| Cable2 | ZC-70 | SQUID_A reads open |
| Cable1 | ZC-39 | SQUID_C and SQUID_D read open |
| Cable3 | ZC-13 | SQUID_C and Feedback_C read open |
| 1430 | Check ZC-70 on bench: SQUID_A indeed reads open, other SQUIDs OK. Take cover off of SQUID card: inspect wirebonds with magnifying glass. They all seem to be OK. |
|---|---|
| 1515 | Prepare ZC-74 for wirebonding (this SQUET has not been modified, planning to reduce all four shunt resistances). But as it turns out, the wirebonder in the Hanany lab (wirebonder is now managed by Vlad Pribiag) is down, needs repairs. Don't know when that will happen, talked to Paul Crowell about it. |
| 1615 | Work on shorts on Tower Face 6 wires that we replaced yesterday. Looks like they are all fixed. Start reattaching the cover plates, we'll finish later. |
| 1735 | Bring SQUET ZC-74 to Ke Wang lab. Wei Ren helped us with Ke's wirebonder (which is the same kind as the other one). Reduced shunts on all four, although didn't quite manage to get double bonds on the bottom two. Used wirebonder power 375/350 (reduced from 475/350), bond time 40/40. Scraped copper with razor blade first. |