MQXFS 1 status Guram Chlachidze Stoyan Stoynev 02
- Slides: 8
MQXFS 1 status Guram Chlachidze Stoyan Stoynev 02 Dec 2015 LARP meeting
Status • L/Q tests and hipot were done on Monday after leads were cut • The magnet was pulled out of the VMTF after this • It is being examined on a table (horizontal position): first layer of the pizza box G 10 cover was removed • Negative lead is compromised inside the pizza box (see pictures), and positive lead seems in a better shape – visually only at this point – Need to inspect leads further to the magnet, in the pizza box supports where leads are in G 10 enclosure • Indications up to now are that the magnet itself is in good condition (as it was before cool down) – No quench developed inside the magnet 2
Assessing the damage (pictures) Support plate Lambda plate Support plate Pizza box 3
Assessing the damage (pictures) 2 Pizza box 4
Quench detection instrumentation Cu Copper lead VTap. Cl. XXX : Cu-SC 1 VTap. Slbs. XXX : SC 1 -SC 2 VTap. Sls. XXX : SC 2 -SC 3 VTap. Sl. XXX : SC 1 -SC 3 SC 1 SC 2 splice WC Pizza box SC 3 WC is used to define whole/half/quarter coil signals Magnet (volume) A 1 splice A 2 Lambda plate Support plate A 1 -A 2 is the first segment inside the magnet 5
L/Q measurements and hipot Measured at LBNL Frequency (Hz) Inductance (m. H) Q Factor 20 100 120 1000 10. 915 7. 9003 7. 5369 3. 8524 1. 433 2. 002 2. 012 1. 718 Measured at Fermilab 10/22/2015 Inductance (m. H) Q Factor 10. 92 7. 9077 7. 5445 1. 299 1. 92 1. 945 3. 8541 1. 707 Measured at Fermilab 11/20/2015 Measured at Fermilab 11/30/2015 Inductance (m. H) Q Factor 11. 07 8. 3987 8. 0507 3. 9837 0. 4053 1. 07 1. 185 1. 346 11. 06 8. 4378 8. 1031 4. 4195 1. 344 2. 156 2. 183 1. 82 Latest L/Q measurements are consistent with the initial tests of the magnet (within several per cent) Coil-to-ground hipotting was performed (at VMTF; leads were cut above the pizza box): At 1000 V the leak current was 0. 05 A - consistent with previous measurements. 6
Quench current and inductive voltage The Whole coil voltage was measured and in addition calculated. The calculation assumes inductance of Current magnitude for 10. 3 m. H for the magnet and is based on Quench 1 is normalized to match the Quench 2 magnitude the current profile. An averaging over 10 measurement points is made (points are at ~ 0. 1 ms intervals). Direct measurements Quench #1 ~ -450 V Quench #2 ~ -500 V The maximum voltage at the magnet was below 1000 V. 7
MIITs Studies not finalized, based on hypothesis that quench was detected in negative half-coil and quench data are available only for the positive lead FIRST QUENCH: Quenching was happening for about 80 s in the SC 2 -SC 3 segment. There is no voltage increase in the first (or any) segment inside the magnet. WC-A 1 (not a real segment) was quenching for ~ 10 s. MIITS in negative half-coil (-10 s to inf): 139 MIITS in positive SC lead between the magnet and the header (-80 s to inf): 741 SECOND QUENCH: Quenching was happening for about 100 s in the SC 2 -SC 3 segment. There is no voltage increase in the first (or any) segment inside the magnet. WC-A 1 (not a real segment) was for ~ 10 s. MIITS in negative half-coil (-10 s to inf): 115 MIITS in positive SC lead between the magnet and the header (-80 s to inf): 590 8
