Superconducting coils for damage studies

This page was created as source of information about small racetrack superconducting coils created for damage study foreseen in October 2022.

1. Measuring the gap size

The gap, where wire will be placed was designed to have a width of 4.9 mm (0.1 mm). To check this, twelve different pieces were measured with micrometer (precision 0.0001 mm).

Screenshot_2022-01-03_at_14.13.48.png

It could be seen from the attached table that, the actual size of the gap is in fact more than 0.02 mm bigger.

2. Labeling the coils

To distinguish between coils, they were labeled with numbers between 0-29. The label is always on side where the winding is started. Following table specifies the coils.

Coil's number Winding material Tension Additional information Washers inserted Current status G10 holder on Location
0 NbTi 8 kg Used for test-winding with copper Yes Qualified no UniGe
1 NbTi 8 kg   Yes Qualified no UniGe
2 NbTi 8 kg   Yes Qualified no UniGe
3 NbTi 8 kg   Yes Winded no UniGe
4 NbTi 8 kg On terminal the insulation is broken Yes Winded X X
5 NbTi 8 kg   Yes Winded no UniGe
6 NbTi 8 kg   Yes Winded no UniGe
7 NbTi 8 kg   Yes Winded no UniGe
8 NbTi 8 kg   Yes Winded no UniGe
9 NbTi 8 kg   Yes Winded no UniGe
10 NbTi 8 kg   Yes Qualified no UniGe
11 NbTi 8 kg   Yes Winded no UniGe
12 NbTi 8 kg   Yes Winded no UniGe
13 Nb3Sn 5 kg   Yes Unreacted no office
14 NbTi 8 kg   Yes Winded yes UniGe
15 NbTi 8 kg   Yes Winded yes UniGe
16 Nb3Sn 5 kg Test soldering 1 - high temp tape added Yes Reacted yes Polymer lab
17 Nb3Sn 5 kg 1B soldering, A miss - high temp tape added Yes Qualified yes UniGe
18 Nb3Sn 5 kg 1B soldering, impossible to deatach from holder piece   Destroied no office
19 Nb3Sn 5 kg 1C soldering, careless handling, B;C miss - high temp tape added Yes Reacted yes Polymer lab
20 Nb3Sn 5 kg 1C soldering - high temp tape added Yes Reacted yes Polymer lab
21 Nb3Sn 5 kg 1C soldering - high temp tape added Yes Reacted yes Polymer lab
22 Nb3Sn 5 kg 1B soldering - high temp tape added Yes Reacted yes Polymer lab
23 Nb3Sn 5 kg 1B soldering, C miss - high temp tape added Yes Reacted yes Polymer lab
24 Nb3Sn 5 kg 1B soldering Yes Reacted X Polymer lab
25 Nb3Sn 5 kg   Yes Unreacted X Daniel's office
26 Nb3Sn 5 kg 1C soldering - high temp tape added Yes Reacted yes Polymer lab
27 Nb3Sn 5 kg 1B soldering - high temp tape added Yes Reacted yes Polymer lab
28 Nb3Sn 5 kg Test soldering 1, Dismount 1, Polish 1, drilled x 2 second time into copper Yes Impregnated yes UniGe
29 Nb3Sn 5 kg 1C soldering Yes Reacted yes Polymer lab
Test soldering1: coil was in oven @ 230C for 15 minutes, but apparently it was not enoght. After that the soldering paste was scratched away. After that another soldering was performed. Coil stayed in over for 15 minutes at 270C. For soldering a solder with Ag was used.

1B soldering:

  1. Surface was cleaned with the alcohol
  2. Small portion of soldering paste(Sn63Pb37) was applied just on strand
  3. Coils were inserted into furnace for 10 minutes at 250C
  4. It was not enough for 6 coils so another 20 minutes at 260C
  5. Solder soaked in the groves, so small amount of solder was added where needed
  6. Coils were taken out and it was cooling down
  7. Coils were preheted again to 150C for 10 minutes
  8. Voltage taps were soldered to the coil
1C soldering:
  1. Surface was cleaned with the alcohol
  2. Through holders, which hold SC wire one pair of voltage taps was put in
  3. Small portion of soldering paste(Sn63Pb37) was applied just on strand
  4. Coils were inserted into furnace for 20 minutes at 260C
  5. All coils were taken out
  6. Second pair of voltage taps was soldered on hot coils (once soldering paste deliquified)
  7. On coils [19,20,29] during dismounting one voltage tap felt of (tap sticked to overlaying SC strand), so additional soldering of these taps was performed (preheat 10 minutes to 180C then solder)
Dismount 1: dismounting SS holder piece was done by putting a sharp knife in the interface between SS and Cu. By hammer two halfmoons was deatachted.

Polish 1: A small layer of resin after impregnation, which had to be taken out using a sharp knife and brushing mashine. The holes for screwing coil on VTI probe was full of epoxy, so had to be drilled out again.

17/08: new labes were created on last batch of 10 Nb3Sn coils. From #30 to #40. 38, 39 one tap lost => soldered on side. #40 all taps lost => one pair solderd on side.

(34 new is 29 old)

STATUS OF COILS ON 14TH OCTOBER:

Coil's number Winding material Tension Additional information Washers inserted Current status Location
0 NbTi 8 kg Used for test-winding with copper Yes Qualified Cryostat
1 NbTi 8 kg   Yes Qualified Cryostat
2 NbTi 8 kg   Yes Qualified C ryostat
3 NbTi 8 kg   Yes Winded office
4 NbTi 8 kg On terminal the insulation is broken Yes Winded office
5 NbTi 8 kg   Yes Winded  
6 NbTi 8 kg   Yes Winded Cryostat
7 NbTi 8 kg   Yes Winded Cryostat
8 NbTi 8 kg   Yes Winded  
9 NbTi 8 kg   Yes Winded office
10 NbTi 8 kg   Yes Cryostat Cryostat
11 NbTi 8 kg   Yes Winded office
12 NbTi 8 kg   Yes Winded  
14 NbTi 8 kg   Yes Winded Cryostat
15 NbTi 8 kg   Yes Qualified Cryostat

Coil's number Winding material Tension Additional information Washers inserted Current status G10 holder on Location
13 Nb3Sn 5 kg   Yes Unreacted no office
17 Nb3Sn 5 kg 1B soldering, A miss - high temp tape added, first qualified 15th July Yes Qualified yes office
18 Nb3Sn 5 kg 1B soldering, impossible to deatach from holder piece Yes Destroied no office
25 Nb3Sn 5 kg   Yes Unreacted X Daniel's office ?
28 Nb3Sn 5 kg Test soldering 1, Dismount 1, Polish 1, drilled x 2 second time into copper, second qualified on 25th July Yes Qualified yes UniGe

Coil's number Winding material Tension Additional information Washers inserted Current status Location
30 Nb3Sn 5 kg   Yes Qualified Cryostat
31 Nb3Sn 5 kg   Yes Impregnated office
32 Nb3Sn 5 kg   Yes Qualified C ryostat
33 Nb3Sn 5 kg   Yes Qualified Cryostat
34 Nb3Sn 5 kg   Yes Qualified Cryostat
35 Nb3Sn 5 kg   Yes Qualified Cryostat
36 Nb3Sn 5 kg   Yes Qualified Cryostat
37 Nb3Sn 5 kg   Yes Qualified Cryostat
38 Nb3Sn 5 kg   Yes Qualified Cryostat
39 Nb3Sn 5 kg   Yes Impregnated office
40 Nb3Sn 5 kg   Yes Impregnated office
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Topic revision: r27 - 2022-10-14 - DavidGancarcik
 
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