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

Arjan Verweij, AT-MAS, Workshop on test facilities and measurement equipment needed for the LHC exploitation, 12 April 2006 General Fresca was built in 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, Nb 3 Sn) up to cross-section of about 35x35 mm 2 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 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 n  ) 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 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 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 Nb 3 Sn, Nb 3 Al 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 Programs for coming years 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 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.