Notes from meeting

Participants : Herve allain, David Vincent, Nicolas Commaux, Patrick Graffin, Clement Lorin, Damien Simon, Jean Marc Gheller (CEA)

Carlo Petrone, Arnaud Foussat (CERN)

1. STAARQ test station layout by J.M Gheller

The main features and scope of supply of the magnetic measurement shaft categories for MQ and MQYY to be cold tested on new STAARQ test station were presented.

• 2 MQYYs (4.03 m long), 6kA
  • aperture 90 mm
  • MQYY magnetic length 3.7 m
  • anticryostat inner diameter 66 mm
• 6 MQs (3.45 mlong), 13kA
  • aperture 56 mm
  • magnetic length 3.2 m
  • anticryostat inner diameter 40 mm

The CAD layout of the station area for magnet uplifting, rotation, removal of transport corset jig was shown

The access insert preparation platform will use two levels in order to perform splices, to install instrumentation, the AC+MM coils mechanical assembly  and to carry out related connections at the top cryostat level.

The magnet once connected on insert platform shall be moved out through the side of the insert platform once magnet is fully equipped.

As reminded, the design of lambda plate is adaptative to both MM and AC systems size requirements as presented. 

The test cryostat has been designed within the following weight and size limits:

• 12 t magnet weight limit,
• 6 m long
• 660 mm maximum outer diameter

The assembly of the magnet insert resting onto a dummy cryostat flange foresees some possible trial assembly of the lambda plate onto the platform with Fuji pressure sensitive film.

The environment around the cryostat top flange and dimensions was shown to be able to design dedicated AC support jig.

1. AC procurement SCHEDULE- J.M. Gheller

MQYYM:

• The cold test of the MQYYM is planned from April 2020 in the saturated LHe II refurbished existing cryostat and operating cryoplant.
• All the MM shaft components for MQYYM have been delivered at CEA.
• The MRU unit is available and one of the QIM to be used is being assembled, to be shipped from CERN by Feb 2020.

MQ, MQYY:

• The reception of ACs is foreseen to be commissioned mechanically onto the dummy magnet of MQYYM either from the time window in Feb 2021 or from June 2021 depending on the procurement schedule of ACs, MM shafts equipments..

1. MM shafts design options – C Petrone

Several  existing options for the MM shafts were presented, analysing the pro and cons as function of the technology and budget constraints

The first idea of a scanning coil system to reuse LHC shaft of MQ has been discarded due to extra development and hardware cost

• It was concluded that existing LHC shaft design used glued end interface , not suitable for vertical operation with limited angle using a membrane
• Total cost of translating mechanical structure including motor, encoders  evaluated at 31 kEur. The solution is estimated to be expensive and time consuming for performing all development. The constraint to install all the guiding structure onto the top of cryostat is also a drawback
• CERN has stated that the time and resources to develop the translation system is not available.

The option 1 consists in using one dedicated array of measuring coils in each of two apertures and would require large amount of handling, risky operation.

• Use of 5 sections, 810 mm (MQ), 925 mm (MQYY)
• The MQ length is based on LHC old design also in for sake of comparison
• A 1.5 mm gap on the radius is designed for keeping a clearance into the shaft.
• 2 MRUs would be necessary to perform the measurements.
• CP reminded that the procurement of MRUs is under CERN responsibilities and this option would require two units.

The option 2 would require 2 arrays of coil in each magnet MQ, MQYY with a total of 4 coils

The last option 3 would require 2 coils of MQ type, extended in length to cover both magnet lenght

• The advantage would be to use only one common AC design, one type of mole adapted to length which would allow to save the supply of additional 2 AC and 2 Moles
• As pointed out by D Simon, the drawback is the attenuation on high orders harmonics beyond b6.
• D. Simon also mentioned that in case of option 3, it would then not be necessary to extend the AC and mole length for the MQYY measurement and that the preferred option by default could be based onto the MQ mole design. This case has to be put in balance with the necessity to characterise b14 on optimised MQYY

or novel collared magnet design

The decision on to the option of design is urgent to be taken to optimise the number of segments either to 5 to 6 and the final shaft dimnnsio.

length, to refine the scope of supply and start procurement form 2020.

1. Open design items (all):

• Some guiding plate at bottom and top of the shafts need to be designed to allow centering
• The position and interface of this centering shaft device needs to be checked on the MQ which has the connection box leads at the bottom in test station  
• Assembly sequence :
  • The preferred assembly scenario of the MM shaft is horizontal, insertion should be done horizontally
  • The handling tooling of AC and insertion of moles are not yet designed, CEA shall evaluate the possibility to insert successive segments of the shaft into the anticryostat which would require a rolling system. The handling feature could use the upper bell by adding anchoring functionalities.
  • The uplifting handling tool of the assembly shat and AC has to be designed. As discussed the first steps of insertion of MM segments should be attended by CERN specialist at the start of MM campaign.
• The question of a fast DAQ MM coils used as Quench analysis tool option wlll be checked by CEA, especially for MQ without voltage taps
• Design of MRU support
  • Supporting bars with possible stabilizers shall be added to react the torque due to MRU. Top clamping support onto the MRU to be added.
  • It is requested to increase the support pads diameter welded onto the ISO K 400 mm flange to screw the support posts of MRU
  • C. Petrone proposes to add a second bellow to compensate the alignment angles of the MRU.
• The electrical insulation of shaft shall be checked by CEA designer.
• Current readout : The signal of magnet current readout need to be transmitted to the MM system with a minimum precision of 100 ppm.
• AC heaters as based on the example of HLLHC heaters onto a pipe diameter 150 mm was shown.  The idea by CEA is to use several circuits to allow minimum heating configuration in case of failure mode. A total of heating power 10, 15 W is planned, to be confirmed by H Allain

1. Test station area visit (All):

The test cryostat hall area to be refurbished has been visited. A pit shall be drilled in the zone of the future insert for preparation work.

The possible locations of the MM system working area requirement of minimum 8 m2 , less than 8 m away from cryostat.

The available floor area is located under the main 20 kA busbars routed at 3 m height and the impact from the bus magnetic field should be assessed.

1. Action items:

A00 -The final option amongst available advanced design of scope of supply of shafts and anticryostats has to be decided by CEA, CERN management as function of budget constraints and available resources.

A01- CEA to design the interface holes in end plates of magnet for the MM shaft centering device.

A02-  As a total of 220 ke budget is needed to develop dedicated measurement ACs, Moles for the MQYY. Action on CERN to clarify the availability of the budget

A03 - A preliminary estimate of the need for the intervention by CERN personnel on CEA site for the preparation and operation start, shall be done by DS.

A04 – The stability of PC current is required and its measurement accuracy on the station shall be confirmed by CEA.

A05 – Drawing approval: The future assembly drawings of the magnetic measuring shafts by CERN shall be validated by STAARQ team

The assembly sequence drawing of shafts into the AC by CEA shall be checked,  validated by CERN.

A06 – A design review of open points abovementionned shall be organised by CEA before launch of hardware procurement.