A Swiss intergovernmental organization / research centre is looking for supplier of around 3000 shielding elements made from Tungsten Heavy Alloy (WHA) with low magnetic permeability.
The partner sought for a manufacturing agreement will be able to manufacture and deliver the shielding elements according to the tolerances listed.
The accelerator currently used by the Swiss NGO is installed in a 27 km circumference tunnel, about 100 m underground. Its design is based on superconducting twin-aperture cryo-magnets which operate in a superfluid helium bath at 1.9 K.
A project is running with the aim to upgrade the collider after 2020-2025 in order to maintain scientific progress and exploit its full capacity. By increasing its peak luminosity by a factor five over nominal value it will be able to reach a higher level of integrated luminosity, nearly ten times the initial design target. To this aim, the research centre is exploring new beam configurations and new advanced technologies in the domain of superconductivity, cryogenics, rad-hard materials, electronics and remote handling.
New beam screens are being designed for the beam apertures of the new cryo-magnets to ensure the required beam aperture while maintaining the ultra-high beam vacuum.
The beam screens will be equipped with tungsten heavy alloy shielding elements to intercept collision debris from the experiments, in order to minimise the heat load to the 1.9 K cryogenic system.
The Swiss NGO is looking for partners able to fulfil a manufacturing agreement for these types of tungsten shielding elements, according to the specifications detailed in the following and to drawings that will be provided separately.
- Type of partner sought: The chemical composition shall be in accordance with the following parameters:
Min W : 95% (The minimum percentage of tungsten shall be respected to ensure the efficiency of the shielding elements)
Max Cu+Ni : 5% (The percentage of copper and nickel shall be respected to ensure the mechanical properties)
Max Co : 0.1% (The percentage of cobalt shall not be exceeded to limit the residual radioactivity)
Max Fe : 0.003% (The maximum percentage of iron shall be respected to ensure the magnetic properties stipulated below)
Magnetic permeability of the shielding element should be
- At 60 K and 1×106 A/m : 1.0015
- At 60 K and 6×106 A/m : 1.0005
The finished shielding elements shall not present visible voids and shall be exempt from cracks. The density shall be 18.05 ± 0.3 kg/dm3.
The mechanical properties shall be according to the following:
Tensile strength Rm min 700 MPa
Yield stress Rp0.2% min 600 MPa
Elongation at break A5 min. 5%
Hardness HRC =34
Use of machining coolants/lubricants shall be subject to the Swiss organisation prior approval. Only halogen-free and silicone-free products are allowed.
Wire erosion in an aqueous solution is allowed provided measures are taken to avoid Zn containing residues on the components. Wire erosion in oil is not allowed since the oil residues cannot be sufficiently removed during cleaning.
In order to limit the outgassing rate, the finished shielding elements shall undergo an outgassing treatment under vacuum at =700° C.
- Specific area of activity of the partner: The partner sought is qualified in the manufacturing and testing of tungsten heavy alloy (WHA) parts.
The tasks to be performed by the partner sought:
•Production of the WHA material (forming and sintering);
•Machining of the components according to drawings provided by the Swiss research centre;
•Certificates of each sintering lot demonstrating the characteristics stated in the profile;
•Certificates of the finished shielding elements demonstrating compliance with the drawings;
•Packing of the components;
•Shipping to Switzerland if required.
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