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Transnational AccessMagNet@CERN

WP9b

Marta BajkoCERN TE-MSC TF

The location of MagNet @ CERN

located in point 18 (is building nr.2173 known at CERN as : SM18)

Transnational Access....done?

Search on the CERN PHOTO LAB: “SM18”

Visits with highly qualified guides

Transnational Access:MagNet

…..SM18 is a unique facility at CERN for testing magnets and instrumentation at very low temperature (lowest being 1.9 K) and up to high currents (20 kA). It is equipped with 10 benches for testing superconducting magnets in horizontal position and with 2 vertical cryostats.

The quench onset is in-between Vtaps 2 and 3 . Not in the coil and not in the splices. It is located in the NbTi cable linking the two coils. Heat is propagating from this portion of cable

to Splice 2 and Splice 3.

-0.02 -0.018 -0.016 -0.014 -0.012 -0.01 -0.008 -0.006 -0.004 -0.002 0

-0.01

-0.005

0

0.005

0.01

0.015

0.02Zoomed area of Quench signals

Q1 Diff totQ2 Diff totQ3 Diff totQ5 Diff totU(1,71_1)-U(71_1,2)U(3,4) Splice 3U(161_1,2) Splice 2

Time [s]

Vol

tage

[v]

0)4,3(

0)2,1_71()1_71,1(

:

0)2,1(

U

and

UU

because

U

0)6,4()4,1( UUDiff tot

)4,3()3,2()2,1()4,1( UUUU

Indicates a quench onset in: )4,1(U

which is composed as following:

)3,2()4,1( UU

the signals

therefore we can only conclude that:

THRESHOLD of detection and protection: 50 mV, 10 ms

WP09 Objectives

….. to carry out: tests of superconducting magnets and instrumentation

FReSCa2 structure in LN2

WP09 Objectives

….. to carry out: tests for superconducting

magnets and instrumentation …..

Temperature measurement with

Optical Fiber

1544.4 1544.6 1544.8 1545 1545.2 1545.4 1545.6 1545.8 1546 1546.2 1546.4

-55

-50

-45

-40

-35

-30

-25

-20

-15

Wavelength [nm]

Am

plitu

de [

dBm

]

Axial FBGs

before gluingafter gluingunder pressurepressure release

Axial strain measurement on a magnet structure based on Optical Fiber

measurements

TaB

B

)()1(

WP09 Objectives…..CERN will offer infrastructure…..CERN will offer infrastructure, equipment ( including handling)…..CERN will offer infrastructure, equipment ( including handling) and expert support……

Infrastructure: SM18 layout

Horizontal test benches for 1.9 K or 4.2 K operation

Vertical test benchesfor 1.9-20 K operation

Vertical test installationsfor 77 K operation

Zone dedicated to the RF cavity activities for 1.9 K or 4.2 K operation

Infrastructure: horizontal test benches

From the initially built 12 horizontal benches 10 are operational today.

Horizontal benchesMagnet weight: 25 tonnesOperation temperature: 1. 9KMax. current in the magnet: 13 kAMax. pressure in case of quench : 20 barsMax. test voltage : 3 kV

The cooling is done in 3 steps: a. 300-80 K with LN2 cooled He gas, b. from 80-4.2 K with He gas and LHe and c. from 4.2-1.9 K by pumping the LHe of the

heat exchanger.

Cooling capacity:6 kW power plant sheared by RF and Magnets25 g/s total pumping capacity

Is heavy and expensive to adapt them!!

Magnet need to have its own cryostat!!

1 Cluster equipped with Energy Extraction system up to 80 mOHM

They are grouped in set of 2 benches forming a cluster.Each cluster is equipped by a set of equipment: PC, DAQ

Powering capacity: 4 x 14 kA/16V 1 x 17 kA/60 V

Infrastructure: vertical cryostats or feed box

HFM cryostat

20 kA power converter

Control Room

Valve box

DAQ

Cold buffer

Cryogenic ControlCryogenic rack

10 kA power converter

Pumping line

20 kA water cooled cables

Magnet weight: few kg- 15 tonnesOperation temperature: 4.2 K and 1. 9KMax. current in the magnet: 20 kA/24 VMax. pressure in case of quench: 3 barsMax. test voltage : 1 kV

The cooling is done with He gas and LHe. From 4.2-1.9 K by pumping the LHe of the heat exchanger of the cryostat (when we have the lambda plate).48 h cooling time!

Vertical benches ( cryostats)

Magnet to be tested without its own cryostat!! Cryostat 1LONG

Cryostat 2DIODES /LEADS

Useful length (mm) 3800 1600Useful diameter (mm) 600 500

Cooling time 4.2 K (h) 44 5Cooling time 1.9 K (h) 12 2.5Consumption (l) 7300/8100 1100Consumption rate(l/h)

95/115 75

Working temp (K) 1.9 - 4.2 4.2 - 50Working pressure (mbar)

1250 1250

Max weight (t) 6 1.5Max energy (kJ) 500Nr of current leads( conventional)

2 x 13 kA +1 x 6 kA

2 x 15 kA

The station designed for “Sc Fast Cycled Magnet, and “Sc Link”

Supercritical He Feed Box

Magnet or Sc Link need to have its own cryostat!!

Energy Extraction system 5- 60 mOHM

Infrastructure: cryostats for 77 K

LN2 tank

Cryostat borrowed from RF

Magnet Flushing Station recuperated from LHC

Main Magnet series tests activity

Transfer lines

Control RoomTemporary placed in

the parking area

Magnet weight: 10 tonnesOperation temperature: 77 KMax. current in the magnet: 0 kAMax. pressure in the cryostat : 3 barsOuter diameter: 1.1 mLength: 4 m

The cooling is done with mixture of N2 gasand Liquid N2. Ex.with a DT< 100 K over 2 m and 10 tons cooling was done to 77 K in 2 days .

Vertical benches (cryostats) for 77 K

In addition we are in the phase of procurement of a VTI ( 300 -4.2 K) cryostat equipped with a 0.5 W cryocooler for instrumentation test like Optical Fibre based sensors

Diameter: 10 mmHeight: 50 mmWhereΔT= T1-T2 ≤ 0.5 KT1r-T1 ≤ 0.1 K

T1

T2

T1r

Variable Temperature Insert Cryogen Free Cryostat

Magnet to be tested without its own cryostat!!No possibility for electrical powering !!!!

For small size instrumentation

Our “jargon” with some numbers

Splice resistance measurements …in the range of the nOhm…

Energy Extraction with Dump resistor ….ms extraction time for energies up to 0.5 MJ

Quench detection thresholds…in the range of 50 mV and 10 ms verification timeWe use specific electronics developed for quench detection with differential signals.

Inductance measurements… also used for short detection

High Voltage test…in the range of the kV

AC losses …Specific dedicated equipment

Quench localization…with V taps or quench antennas…

Strain measurement…with resistive gauges or with optical fibers…

For operation…Temperature sensors up to 1.9 KPressure gaugesLHe level gauges LN2 level gauges

Quench heater powering…by discharge of capacitor benches

Magnetic measurements…field quality, transfer functions…

This is part of a qualification program for a magnet…. We do these measurements, we develop our equipment and we constantly work on the improvement with specialist across CERN in order to have the most reliable measurements done in the most efficient way.

Safety for users

The main hazards are linked to the use of cryogenics, high currents, high voltages, heavy loads, laser radiation, RF cavity radiation and a complex distribution of electricity and cryogenic fluids and gases.

Link to the Sm18 test facility web page

Modus Operandi for MagNet

Selection Panel (with several experts in testing)

will analyse from potential users of the installations of MagNet the proposals

• Feasibility of the experiment with the existing equipment and within the

• Proposed timeline • taking into account the CERN

needs of the installations and• Giving them the highest priority

• Scientific value of the potential result for the community

• Synergy with R&D activity in the field of Superconductivity and in general accelerators

the Approved experimentswill have the occasion to profit of the installations for 2 unit access /year for instrumentation test, 8 unit access/ year for magnet

test and 2 extra unit access/ year for additional magnetic measurements

The budget from FP7 will be used to installations, dismantling, transport of heavy equipment for test and for travel expenses of users; for expenses related to the stay at CERN to prepare and carry out (with the collaboration of CERN experts), and analyse the test results; and for transport of material related to experiments at the facility.

Link to the Sm18 test facility web page

Marta Bajko CERN

Thanks for your attention