Amendment 1 - 12 TESLA CRYOMAGNET Questions.pdf

12 TESLA CRYOMAGNET – 1333ND20QNB610475 – Questions with Responses

General Note: This requirement is for a complete and functioning Cryomagnet system. Offerors interested in this project have been directed, in the Statement of Work, to submit a Conceptual Design for their proposed system. There is no expectation of a near-completion, detailed plan/schematic of the proposed system during the solicitation response period.

The conceptual design is intended to be a generalized plan of action, in accordance with the Solicitation package (Statement of work, attachments and any amendments/Q&A), and consists of:

- An outlined summary of the steps a vendor will propose to accomplish the project goal.

- A list of deliverables.

- A list of any equipment (major and ancillary), with model numbers, necessary to manufacture the complete

12 Tesla superconducting magnet system.

- A list of any subset equipment being outsourced.

- A high-level estimated timeline (draft Gantt chart) to be delivered with the quote response. Further refinement of the Gantt chart will be developed after award.

Evaluations will be conducted on this design and the information provided to demonstrate the ability for the design to successfully fulfil the needs of this requirement. The finalization of this design and implementation of the manufacturing process will follow any award resulting from this solicitation.

Reference Question with Response

Page 4, Due date for quotations

The requirement SOW is a complex, custom-designed system. As such it requires a priori superconducting magnet design. We therefore request a minimum extension of 6 weeks to the August 25, 2020 date (i.e. to October 06, 2020) in order that the necessary design work and diligence can be applied. Please also note the reliance upon the provision of further information from NIST in this regard as critical design inputs, including responses to these questions.

RESPONSE: NCNR must make an award by 30 September 2020 to avoid losing the money for this requirement. We will grant an extension to 10 September 2020 at 2PM EDT. (see General Note above)

General There are likely to be design trade-offs which will require NIST feedback for optimization.

Please indicate if/how this may be possible – for example, is technical dialogue possible?

RESPONSE: Once an award has been made and a proposed conceptual design has been selected, there would be discussion between the NCNR technical team and the chosen vendor to optimize the final design.

Background Is a vendor requirement implied by “safeguards to protect both the equipment and personnel during operation”? For example, interlocks?

RESPONSE: Yes. Protection from runaway magnetic field, vacuum space overpressure safeguards, overtemperature safeguards for samples and magnet, and other such safeguards that would be necessary to protect equipment and personnel. Proximity interlocks will not be required from the vendor, for example.

Reference Question with Response

5.2.1 Please comment further on the restriction to air-cooled compressors. This restriction significantly limits the choice of pulse tube refrigerator which can be used on the system.

Since chilled water is necessary for turbo pumps, can this also be used for a water-cooled compressor which will enable a wider cryocooler choice and potentially smaller footprint.

RESPONSE: Chilled water for any components is not acceptable. GM style cryocoolers with sufficient cooling power are on the market that run on air-cooled compressors. NIST currently has a system such as this that sufficiently cools our 10T magnet. However, NIST does not oppose the use of Pulse Tube cryocoolers in the design of new 12T magnet system.

4.2.7 What neutron absorbing material is required? (material and thickness)

RESPONSE: Any neutron absorbing material excluding cadmium is acceptable.

4.2.8 Please confirm that the outer vacuum tail should be an Aluminum/Al alloy tail with 360-degree circumferential beam and height to match that of magnet access.

RESPONSE: The entire azimuthal angle for the beam path must be Aluminum/AL alloy, including the outer vacuum tail. The angle covering the dark angle does not need to be thinned.

4.2.8 What grades of Aluminum/Al alloy are acceptable?

RESPONSE: 6061 is typical, other low Cd content alloys are acceptable; 4000, 5000, and 6000 series alloys.

4.2.10 How have the maximum axial and lateral forces on the magnet been calculated, without having the actual magnet model? Can the environment information be provided so that the vendor can perform their own calculations and identify any trade-offs, using the actual magnet design model?

RESPONSE: NCNR has a number of superconducting magnets and have done the calculations based on prior experience. Once an award has been made and a proposed conceptual design has been selected, NCNR will work with the vendor to refine the models for the final design.

4.2.10 Please clarify the requirement for “no magnetic materials”. Stainless steel is typically an essential structural material in such systems, and while nominally non-magnetic does typically contain some residual magnetic traces.

RESPONSE: Materials that will have a relative magnetic permeability in the range from 1.000 to 1.01 when measured at magnetizing forces of 200 Oersteds (16k A/m).

4.2.10 What is the over-arching driving requirement between magnetic field, azimuthal angle, and the stated maximum dimensions? i.e. to which specification should the vendor target their design optimization?

RESPONSE: The stated maximum dimensions are hard limits to ensure fit within the existing instrument enclosures. Azimuthal angle and field are as specified in the SOW.

4.2.10 “Total system height”: Is there an allowance additional to the total height stated, for sample loading/extraction?

RESPONSE: Sample loading and extraction allowance is 2800mm above the flange provided the sample stick is normally removed during operation

Goniometer Is there a/what is the weight limit for the system on the goniometer?

RESPONSE: 400 kg

Due Date This is an unreasonably fast turnaround and we request an extension of at least 7 days, for not less than 14 days after clarifications are released for preparation of the tender submission.

RESPONSE: NCNR must make an award by 30 September 2020 to avoid losing the money for this requirement. We will grant an extension to 10 September 2020 at 2PM EDT.

Submission Please clarify if there are any email format or firewall concerns for this submission. Per specifications in Quotation Preparation Instructions, we understand that five independent PDF documents should be provided, with cross-references as necessary. If any file size restriction exists, accommodations can be made.

RESPONSE: The NIST maximum size of a file is 25MB per email.

4.1.1 Please confirm this requirement is for conduction-cooled cryogen free operation only; the phrase ‘…use of an initial charge of helium gas to initialize a self-cooling cryogenic system…’ appears to allow for a re-condensing liquid helium cryostat type.

RESPONSE: The system must be operable continuously with no initial or ongoing charge of LIQUID cryogens. This does not preclude gaseous helium from condensing within the system as needed for cooling the VTI.

4.1.3.6 Please clarify what is meant by the ‘…VTI…’. The requirement states it is for an integrated Dilution Refrigerator (DR) , this VTI statement appears to be consistent with a removable DR insert and not with an integrated DR.

RESPONSE: The system is an integrated Dilution Refrigerator. VTI refers to the place where the sample is inserted into. This system does not have a removable Dilution Refrigerator.

4.1.4 The magnet temperature change limit of + 1K during sample change is partly in the hands of the care and skill of the operator. Further, if the design of the superconducting magnet has a higher temperature rise tolerance than + 1K is this permitted by NCNR? We do not wish to be limited in our design flexibility.

RESPONSE: The design of the system and the training provided by the vendor must be such that a trained operator can perform sample change without warming the magnet beyond its superconducting phase.

4.1.6.1; 4.1.7; 4.3.2, 4.3.2.4

Please clarify the required operating temperature for the DR; there appears to be some inconsistency in the sample thermometry and control requirements, please clarify:

1. Section 4.1.6.1 requires the sample probe to have calibrated sensors for 0.02K to 40 K;

RESPONSE: It is necessary to have multiple sensors that are optimized and different ranges in order to cover the full range of possible sample temperatures.

2. Section 4.1.7 requires a maximum sample temperature of 100 K and a minimum of 0.050 K with a stability of ±0.001K (over 48 hours);

RESPONSE: It is necessary to have multiple sensors that are optimized and different ranges in order to cover the full range of possible sample temperatures.

3. Section 4.3.2 requires the temperature controller to be optimised for < 50mK control;

RESPONSE: This is correct.

4. Section 4.3.2.4, the DR temperature control requirement, requires a sample temperature stability of ±500 mK over the operating range.

RESPONSE: [Correction] The ramping is changed to “as low as 0.001 K/m” and the control stability is changed to “10 microK at 50 mK”.

4.1.7 Please confirm the 100 microWatt cooling power at 100 mK requirement is in the mixing chamber and not at the sample.

RESPONSE: Yes.

Please clarify the role of the optional ‘sock’ and its associated heating requirement.

RESPONSE: If the system design requires a sock to condense recirculating helium, then the heater exists to warm the sock in the event of a capillary ice blockage.

Cross-referencing to section 4.1.3.6 please clarify the requirement and the role of the VTI and its needle valve heater.

RESPONSE: Heater for the VTI needle valve exists to warm the associated capillary in the event of an ice blockage.

4.2.7 Please define ‘…near…’. This needs to be more clearly specified. We plan to place cd shielding to protect the surface of the magnet exposed to the beam-path but confirm this cd shielding will not impede the other related requirements (split, vertical access, azimuthal access).

RESPONSE: This is a radiation safety requirement due to high prompt gamma radiation in cadmium exposed to neutrons. Cadmium is not permitted because Cadmium will cause a radiological safety concern because of elevated prompt-gamma radiation

4.2.10 Please clarify the magnet performance requirements (homogeneity, 5G line, split and vertical angle) are in conflict according to our technical evaluation. Does NCNR have any potential concession in the magnet requirement? Meeting what appear to be the key requirements (outer diameter limit of cryostat, split & vertical angle, operating field 12T) makes:

a. the 5G line at 2m not possible, and

b. homogeneity of 1 % in 2cm DSV (the 0.6% in 1 cm DSV is met) not possible to achieve in our initial evaluation.

RESPONSE: Yes. There is flexibility for consideration in both requirements.

4.3.9 Please clarify the requirement for provision of source code for magnet temperature protection.

RESPONSE: This requirement is to ensure that NCNR has full access to view and change all parameters for the magnet temperature protection. If such software is produced by the vendor for this system, then the source code is a deliverable.

4.5.1 Please clarify the lift test certification requirement. We routinely provide certified lift eyes/lift points, but do not hold a standard certification procedure. Please advise any standards to achieve with the trolley arrangement.

RESPONSE: If the vendor provides full engineering models for liftable items, including center of gravity modelling, and all calculations used to show why each certified lift point was chosen, then NCNR will accept this.