B163 - FRESCA

1. B163 - FRESCA Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation , 12 April 2006

2. General • Fresca was built in 1995-1998 and has been operational since then. • Presently run by 2 staff, 1 PT support and also used by one PhD. • FEATURES: • 88 mm dipole up to 10.3T (at 1.9 K), housed in an independently cooled cryostat. • Test volume of about 600 mm x 70 mm  • Samples (NbTi, Nb3Sn) up to cross-section of about 35x35 mm2 can be measured under pressure in a sample holder. • Sample current with external 32 kA PS or internal s.c. transformer (>36 kA). • Possibility of up to 200 measurement wires. • Automatic data acquisition for most of the tests. • Measurement devices: 4 ch x 1 MHz, 16 ch x 100 kHz, 32 ch x 200 kHz acquisition, 30 ch x 10 Hz Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation , 12 April 2006

3. Type of measurements • UI-measurements (as function of B, B-direction, T and dI/dt)  Ic, Iq, n-value • UB-measurements (as function of I, B-direction, T and dB/dt) flux jump stability • RRR measurement (as function of B if needed) • Measurement of the self field along the cable  transport current distribution among the strands, BICCs • Measurement of splice/joint resistances (accuracy better than 0.05 nW) • Measurement of (Minimum) Quench Energy (as function of B, I, T, heater position, heat pulse duration) • Measurement of quench velocity (as function of B, T) Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation , 12 April 2006

4. Programs for coming years • LHC reception (4 cool-downs): • measurements on samples of final cable deliveries • Target: approve final cables of the LHC contracts • LHC feedback program (4 ? cool-downs per year): • LHC NbTi cables (01x-07x) • Target: Perform any type of measurement that could help to better understand magnet (quench) behaviour of the LHC magnets • Splice-uniformity program (4 cool-downs): • Measurement of Ic, Iq and n as function of B,T,dI/dt • Joints with lengths of 4, 6, 8, 10, 12 cm • Target: understand to what extent non-uniform joints/splices influence the electrical characteristics of a cable. Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation , 12 April 2006

5. Programs for coming years • MQE program (10 long cool-downs per year): • various Ra and Rc, • with/without core, impregnation, soldering etc • NbTi with Cu or resistive matrix • Target: understanding beam loss sensitivity, validation & optimization of cables for new applications (cycled magnets, ...), PhD work G. Willering • GSI-MQE program (3 long cool-downs): • 3 cored NbTi cables with low/medium/high Ra • Target: understanding if Ra has to be as small as possible in order to imrpove stability • Nb3Sn, Nb3Al program (4 long cool-downs per year): • FermiLab, Twente, NED? • RRP, PIT, (M)JR, RHQT • Target: Flux jump stability, MQE, Ic(B,T)  cable degradation, pressure dependence? Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation , 12 April 2006

6. Programs for coming years • Cold-weld program (4 cool-downs): • Measurement of Ic, Iq and n as function of B,T,dI/dt • Cable samples with 1, 4, 10, 18 cold welds • Target: understand to what extent cold-welds influence the electrical characteristics of a cable. • Transformer program (3 cool-downs): • increase the current of the transfomer (towards 50 kA) • improve the accuracy of the regulation and measurement system. • Target: reduce helium consumption, and enable testing of Nb3Sn cables to higher currents Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation , 12 April 2006