Status of the PANDA Solenoid Magnet Production in BINP PANDA meeting 2017 September 4-9 E.Pyata

PANDA meeting 2017 September 4-9 E.Pyata PANDA solenoid magnet The PANDA solenoid is designed to provide a magnetic field of 2 T with a uniformity of ± 2% and radial magnetic field integral in the range 0 to 2 mm over the central tracking region. The magnet is characterized by a warm bore of 1.9 m diameter, a free length of 4 m and 22.4 MJ of stored energy. Figure 1. Artistic cut side view of the solenoid magnet including contained detector systems. PANDA meeting 2017 September 4-9 E.Pyata

The main requirements to magnetic field of the PANDA solenoid magnet Since PANDA is a fixed target experiment, the main technical challenge is the insertion of a warm target pipe vertically to the solenoid axis in correspondence with the interaction point located at 1/3 of the length of the solenoid. In order to meet the above requirement while satisfying the magnetic field homogeneity constraints, the magnet is split in 3 interconnected coil modules Magnetic field In the region occupied by the MVD and the central tracker there are very stringent requirements for the magnetic field homogeneity. According to these, the absolute magnitude of the field shall not vary by more than 2% from the nominal field of 2 T over the whole tracker region, which is the main aim of the magnet design. Parameters of the magnetic field are summarized in Table 1. Table 1. Parameters of the magnetic fields. PANDA meeting 2017 September 4-9 E.Pyata

The main milestones of production of the PANDA solenoid magnet The scope of delivery includes: Magnetic and engineering design of the magnet including tools and support; Production and delivery of the magnet (consisting of yoke, cold mass and cryostat, alignment components, proximity cryogenics, support frame and platform beams) and all tools; Power converter and quench protection and instrumentation. Start contract 03/2017 Control assembling of the Yoke of solenoid at the BINP site 09/2019 Magnetic tests of the PANDA solenoid including safety system and electrical components at BINP (additional contract) 02 - 07/2020 Assembling and tests at the FAIR site Assembling of the Yoke at Darmstadt 03/2021 Acceptant tests at FAIR 08/2022 Installation of the PANDA solenoid magnet at worked position and start final acceptance tests 01/2023 Table 2. The main milestones. PANDA meeting 2017 September 4-9 E.Pyata

The main milestones of the yoke production Memorandum BINP/ plant SibElectroTherm (SET) 05/2017 Presentation design of the yoke after technological work of drawings in FAIR 20-25/07/2017 PDR of the yoke 25-29/09/2017 FDR of the yoke 11/2017 Contract with SET Purchasing raw materials 02/2018 Start of production 12/2017 Production of the first barrel octant 03/2018 Production of the all barrel octants 11/2018 Production of the frame and beams Production of the doors 03/2019 Control assembling at SET 04/2019 Finalization of the parts 05/2019 Assembling of the Yoke at BINP 09/2019 Table 3. The main milestones of the yoke production. PANDA meeting 2017 September 4-9 E.Pyata

Figure 2. Process Flow Diagram of the PANDA cryogenic system. PANDA solenoid 2017, TDR Flowscheme The Process Flow Diagram (PFD) of the PANDA cryogenic system proposed by Udo Wagner (CERN) is shown in Fig 2. The main components of the cryogenic system are: 1. the cryostat, which includes: • the superconducting coil cooled indirectly via the thermal contact with the aluminum support cylinder; • thermal shields cooled by gaseous helium; • the vacuum vessel; 2. the control dewar, which includes: • a vessel for liquid helium; • current leads; • valves, gauges; • vacuum shell. 3. a transfer line (Chimney) connecting the vacuum vessels of cryostat and control dewar; 4. transfer lines (TL) connecting refrigerator and control dewar. Figure 2. Process Flow Diagram of the PANDA cryogenic system. Flowscheme of the PANDA solenoid was approved. PANDA meeting 2017 September 4-9 E.Pyata

Figure 3. Modifying design of the cryostat and supports. CDR of cryostat and Dewar box - 12/2017 TDR cryostat vacuum vessel is designed as two concentric shells with thick annular end plates, all made of aluminum alloy 50833. The nominal wall thickness is 45 mm for the outer cryostat shell and 40 mm for the inner shell. The thickness of the flanges is 55 mm. The large thickness of the shells allows to minimize the displacement of the cold mass under the action of magnetic forces relative to its nominal position. The deviation of the coil position from the nominal one within allowable limits may lead to magnetic decentering forces applied to the coil in axial direction and in a direction normal to the cryostat axis up to 168 kN and 51 kN respectively. So the total maximal force which can be applied to the cryostat in the horizontal plane (additionally taking into account the seismic acceleration of 0.75 m/s2) can be up to 185 kN. The exact location of the cold mass inside the cryostat after its assembly should be defined with maximum precision. This is necessary to determine an optimal position of the superconducting coil inside the yoke aperture. The target vertical pipe is traversing the magnet upstream of its centre at about 2/3 of the cryostat length. It will pass in between the two sub-coils of the solenoid through a warm bore in the cryostat. Therefore the cryostat for the superconducting coil is has to have two warm bores of 100 mm diameter, one above and one below the target position, to allow for insertion of internal targets. The cold mass of the cryostat is suspended on four vertical rods. Eight horizontal tie rods of radial suspension fix the cold mass against shifts under the action of decentering magnetic forces and seismic loads in lateral direction. The axial tie rods (eight pcs.) hold the cold mass against its shifts due to decentering axial magnetic forces acting both in the cryogenic input direction and in the opposite one, as well as against seismic loads acting in axial direction. The position of the cold mass in axial direction is fixed in the area of the hole for the target (the fixation point is placed asymmetrically with respect to the cryostat center). According to calculations of loads on the support of cold mass made by Helder Pais Da Silva (CERN) the loads are too high and we suggest using a different design of support (Fig. 3). Also material of the vacuum shell of the cryostat is stainless steel now. At this case mechanical and thermal loads should significantly decrease. Figure 3. Modifying design of the cryostat and supports. PANDA meeting 2017 September 4-9 E.Pyata

Figure 4. Longitudinal section of the cryostat with cold mass. PANDA solenoid 2017, cold mass The PANDA solenoid is designed to provide a magnetic field of 2 T over a length of about 4 m in a bore of 1.9 m. The solenoid is split in 3 inter-connected coils. A view of the Target Spectrometer, including the magnet is shown in Figure 1. Each coil is a six layers solenoid enclosed in a coil casing to rigidly contain the internal forces exerted on the conductors due to the magnetic field. The coils and the coil casing constitute the cold mass, which must be maintained at liquid helium temperature (~ 4.2 K) in order for the winding to be in the superconducting state. The cooling of the cold mass is achieved indirectly through the circulation of liquid helium in pipes welded on the coil casing. The TS solenoid is designed to operate at a current of ~5 kA. The conductor is a superconducting NbTi/Cu wire based Rutherford cable co-extruded in a high purity aluminum stabilizing matrix, featuring high electrical and thermal conductivity. The production design and contractual follow-up of the construction of the cold mass including the conductor manufacturing, its integration into the cryostat and test have been committed by the PANDA Collaboration to BINP. Thickness (after cold work) at 300 K mm 7.93 ± 0.03 Width (after cold work) at 300 K 10.95 Critical current (at 4.2 K, 5 T) A > 14690   Critical current (at 4.5 K, 3 T) > 16750 Overall Al/Cu/sc ratio 10.5/1.0/1.0 Aluminum RRR (at 4.2 K, 0 T) > 1000 Al 0.2% yield strength at 300 K MPa > 30 Table 4. Conductor mechanical and electrical parameters. Figure 4. Longitudinal section of the cryostat with cold mass. Figure 5. Cold mass cross-section. PANDA meeting 2017 September 4-9 E.Pyata Figure 6. Drawing of the conductor.

PANDA meeting 2017 July 20-25 E.Pyata Conductor PANDA solenoid 2017, Conductor Cost ??? Conductor`s manufacturers Furukawa, Japan - according to CERN specification, 1.5 year production time But now absent possibility to produce extrusion of Rutherford cable to Al. 2. BINP, 1.1 year production time, if samples will produce according to CERN specification A.A. BOCHVAR HIGH-TECHNOLOGY SCIENTIFIC RESEARCH INSTITUTE FOR INORGANIC MATERIALS (VNIINM), Russia – strands - according to CERN specification VNIINM and k - Rutherford cable, according to CERN specification BINP, extrusion of Rutherford cable to Al, according to CERN specification Hitachi, Japan - according to CERN specification, ? year production time – closed production from 2013 (last project – Mu2e) Supercon, USA - according to CERN specification, ? year production time Production of the Rutherford cable: Furukawa, VNIINM, Supercon, Bruker… PANDA meeting 2017 July 20-25 E.Pyata Conductor

PANDA meeting 2017 September 4-9 E.Pyata PANDA solenoid 2017, Power Supply and Energy Extraction System for the PANDA magnet Responsible person - Dr. Erokhin Alexandr, BINP Requirements for the external protection system (Quench detection and Energy Extraction): The amount of the stored energy to be extracted is 22.4MJ. Stored energy should be extracted to the external dump resistor with the value of 0.1 Ohm. The active elements of the dump resistor should not be hotter than 100C. Power Supply (four VCH1300) – parameters Nominal output power 61,2kWt; Nominal output current 5100А; Nominal output voltage 12V; 8 hours run Stability - < 0.01% from nominal; Output ripples in voltage: 0-300Hz - < 10mV rms, 0-40кГц – < 100mV rms; Control Interface – CAN Form factor 19” x 3U Conceptual Design Report was presented in FAIR GSI, 21.07.2017 FDR - 06/2018 PANDA meeting 2017 September 4-9 E.Pyata

Thank you for your attention PANDA meeting 2017 September 4-9 E.Pyata