LARP MQXF MagnetsCryogenic Testing at Fermilab’s Industrial

Building 1

Roger RabehlTechnical Division/Test & Instrumentation

DepartmentJanuary 31, 2014

Cryogenic Testing of MQXF Magnets at Fermilab

• Operational phase durations for cryogenic testing of MQXF magnets at Fermilab have been estimated for both single and double cold mass cryostats.

• These phases are:– Cool-down from 300 K to 4.5 K– Pump-down from 4.5 K to 1.9 K– Recovery/refill at 4.5 K following a quench– Warm-up from 4.5 K to 300 K

Updated Operational Figures of Merit – Horizontal Testing

• Assumptions: Cool-down and warm-up– Each MQXF cold mass is treated as a 9570 kg, low-

carbon steel lumped capacitance.– 10 g/s He supply flow rate with 75 K DT (FRS: 100

K DT max.).– He supply temperature range of 4.5 – 300 K.– Cool-down: DT = Max. magnet temp. – He supply

temp.– Warm-up: DT = He supply temp. – Min. magnet

temp.

Updated Operational Figures of Merit – Horizontal Testing

• Calculated results: cool-down and warm-up– 1 MQXF• Cool-down to 4.5 K: 68 hr• Warm-up to 300 K: 93 hr

– 2 MQXF• Cool-down to 4.5 K: 137 hr• Warm-up to 300 K: 186 hr

Updated Operational Figures of Merit – Horizontal Testing

• Assumptions: 1.9 K pump-down time– Scales with LHe volume (feedbox below lambda

plate + magnet) using Q2a&b operational data• Feedbox below lambda plate: 400 liters• Q2a&b (cold masses + external HX): 400 liters• MQXF: 250 liters/cold mass

• Feedbox + Q2a&b: 800 liters• Feedbox + 1 MQXF: 650 liters• Feedbox + 2 MQXF: 900 liters

Updated Operational Figures of Merit – Horizontal Testing

• Calculated results: 1.9 K pump-down

* Historically, the first 1.9 K of each day is longer than subsequent pump-downs that day. This is because the test stand is put into overnight condition (i.e., shut off the LHe supply and let the test stand ride on compressor suction) each night with the penalty of refilling and a longer initial pump-down as the test stand re-stabilizes the next day. This strategy needs to be revisited.

1.9 K pump-down[hr]

Q2a&b 3

1 MQXF 2.5

2 MQXF 3.5

Updated Operational Figures of Merit – Horizontal Testing

• Assumptions: 4.5 K recovery/refill following quench– Scales with stored energy using Q2a&b

operational data• Q2a or Q2b: 1.4 MJ• Q2a&b: 2.8 MJ• 1 MQXF: 5.3 MJ• 2 MQXF: 10.6 MJ

Updated Operational Figures of Merit – Horizontal Testing

• Calculated results: 4.5 K recovery/refillStored energy

[MJ]4.5 K recovery/refill

[hr]

Q2a or Q2b 1.4 0.5

Q2a&b 2.8 1

1 MQXF 5.3 2

2 MQXF 10.6 4