MBHSP02 test STATUS and first results Guram Chlachidze for the 11T Test Group March 5, 2013 FERMILAB

Introduction MBHSP02 is a 1 m long prototype of the 11 T dipole magnet with coils #5 and #7 0.7 mm diameter Nb3Sn strand of RRP 150/169 sub-element design 40 strand Rutherford cable with a 11 mm wide and 25 µm thick stainless steel core Round strand parameters provided by OST E. Barzi, D.Turrioni, FERMILAB-TM-2552-TD, 2013

MBHSP02 instrumentation 10 voltage taps on the inner layer (IL) and 9 voltage taps on the outer layer (OL) One voltage tap (VT) was missing before cool-down (05B5) and one VT (07A4) became floating after the ramp # 9

MBHSP02 instrumentation (cont’d) Each coil is equipped with 2 protection heaters Heaters are composed of 2100 mm long, 0.025 mm thick and 21.5 mm wide (in mid-plane) or 26 mm wide (in pole area) stainless steel strips used One layer of Kapton (114 µm) insulation was placed between the heaters and coil

MBHSP02 instrumentation (cont’d) PCB based Quench Antenna (QA) with 3 segments installed on the inner surface of each coil Lead end QA is located at ~ 2 cm from the VTA6 and return end QA is located ~ 2 cm before VTA8 MD LE RE

MBHSP02 instrumentation (cont’d) 61 strain gauges (SG) were installed on shell, coils and bullets for monitoring mechanical strain and coil stresses during the magnet construction and testing 2 resistive temperature sensors (RTD) were mounted at top, middle and bottom of the magnet outer skin

Short sample limit (SSL) estimation Extracted witness samples used for the SSL estimation Load lines were provided by CERN Different parameterization of the critical current density used to compare results E. Barzi, D.Turrioni, FERMILAB-TM-2552-TD, 2013

Test status Warm magnetic measurements Feb 18 Cool-down Feb.19-20 Magnetic measurements at 4.5 K Feb. 22 Quench training at 4.5 K Feb. 23, 25-26 Ramp rate Study Feb. 26 Holding quenches at 4.5 K Feb. 28 Quench training at 1.9 K March 1, 4 Quench training and ramp rate study March 5-7 Holding quenches at 1.9 K March 8 Magnetic measurements at 1.9 K March 11-14 Quench protection study, Energy loss measurements, etc

MBHSP02 Quench Performance

Ramp rate dependence at 4.5 K Quench at 10 A/s developed in b2_b3, all other quenches in a4_a5 segment of coil #7

Splice resistance measurements B1_B2 resistance measured in coil #7 only No indication of problem (0.10 ± 0.16) nΩ More measurements will be done later, including b1_b3 segment in coil #7

Holding quenches at 4.5 K Holding magnet at a pre-set current until spontaneous quench happens Magnet still unstable at 9500 A

Holding quenches at 4.5 K (cont’d) No spikes found before the quench Ramp #30, quench at 10300 A Ramp #31, quench at 9500 A

Voltage Spikes at 4.5 K Voltage spike threshold of 40 mV applied Noise pick up from power supply

Quench locations

Quench locations (cont’d) Most quenches initiated at ends

Quench locations at 4.5 K

Quench locations at 1.9 K

MBHSP02 vs. MBHSP01

Guram Chlachidze, CERN-Fermilab internal review Backup Slides

Quenches in mid-plane block Ramp #28 at 10 A/s