Attachment I - Specifications (Update Dec 7).docx

Specifications X-Ray CT System

I. Background

The Dimensional Metrology Group (DMG) and the Production Systems Group (PSG) at NIST requires an industrial X-Ray computed tomography (XCT) system to be used for several different research and measurement purposes.

The system will be used in the DMG development of error models that predict how different errors in the XCT system, such as geometric misalignments of the components, manifest themselves in XCT measurement results. This will enable NIST to determine a set of test positions for use in performance evaluation standards (ISO 10360 series and ASME B89 series, in particular), which are adequately sensitive to known error sources. For this, NIST requires a system with hardware and software flexibility, especially in access to machine control and the reconstruction process. NIST will use an understanding of the effect of error sources on measurement results along with an error map that NIST generates of the system (using laser interferometry and other tools) to provide estimates of the uncertainty of measurements that are made using the system. This will allow NIST to eventually offer low-volume, specialized, measurement services (calibrations) using the CT system. For this, NIST requires the lowest uncertainties possible. Measurement speed is generally not a concern.

The system will also be used to support PSG research in metal-based Additive Manufacturing (AM). NIST will use the CT system to measure parts to provide information about AM manufacturing processes and parameters. Three current areas of interest are void detection, comparability of CT results to contact-based coordinate measurements (touch-probe CMM) and the uncertainty of CT measurement of complex internal structures made by AM.

Both groups plan to routinely publish data and findings, in international journals and conference proceedings, related to the work described above and other areas of research of interest to NIST and NIST’s partners.

The requirements listed below represent the internal trade-offs that were made in order to support all activities as fully as possible.

II. Scope

NIST requires one (1) industrial X-ray Computed Tomography (XCT) measurement system. This system will be used for XCT performance evaluation research, measurement and analysis of AM parts, and calibration services.

III. Minimum Requirements

The system shall meet or exceed the minimum requirements identified below. All items must be new. Used or remanufactured equipment will not be considered for award. Experimental and prototype items will not be considered. The use of “gray market” components not authorized for sale in the U.S. by the Contractor is not acceptable. All line items shall be shipped in the original manufacturer’s packaging and include all original documentation and software, when applicable.

Contract Line Item Number (CLIN) 0001: The Contractor shall provide one (1) X-Ray CT system that meets the following minimum specifications:

System construction and components

1. The system shall, at a minimum, have four (4) axes of motion for the sample stage (three (3) orthogonal linear motions plus rotation) and one (1) axis of motion for the detector (along the source-to-detector axis). X-ray tube shall remain stationary during all scans (circular, helical, etc).

2. The system shall not rely on the use of coordinate technologies (e.g. touch probes or optical measurement systems) other than x-ray computed tomography to generate measurement results.

3. The sample stage shall be able to be positioned as close to the source as physically possible, and shall be able to travel at least 600 mm along the source-to-detector axis (Z axis, i.e. magnification direction), 250 mm in the up-down direction (Y axis, i.e. gravity direction), and 100 mm in the left-right (X axis) direction.

4. The sample stage shall provide at least 360 degrees of rotation with positioning ability better than or equal to 1 millidegree.

5. The sample stage shall have a centered load capacity of at least 20 kg.

6. The detector shall be variable-focus with a maximum focal distance of at least 1000 mm (source-to-detector). The detector shall have a minimum of 600 mm of travel along the source-to-detector axis.

a. (Stronger consideration will be given for detector motion in the plane of the detector and appropriate reconstruction techniques that result in a larger effective detector size, up to two times in both horizontal and vertical direction of the actual detector area, through the use of stitching.)

b. (Stronger consideration will be given for the ability to achieve improved resolution, up to double what the detector alone is capable of, through a combination of detector motion and software algorithms.)

7. The system shall have encoders on all axes of motion (linear and angular). (Stronger consideration will be given to systems with linear encoders that have resolution of 10 nm or better and accuracy of +/- 3 m or better.)

8. The system shall have an open x-ray tube or tubes in one of the following configurations (a-d). (Stronger consideration will be given for a, b, or c configurations.)

a. 240 kv transmission,

b. 225 kv dual transmission/reflection

c. 225 kv rotating target reflection, or

d. 225 kv reflection

e. 240 kv reflection

9. The x-ray tube voltage shall be user selectable.

10. The x-ray tube current shall be user selectable. If a transmission tube, it shall produce a maximum of at least 50 W of power available at the target. If a directional/reflection tube, it shall produce a maximum of at least 225 W of power available at the target.

11. The x-ray tube shall meet one of the following requirements related to spot size,

a. For a 240 kv transmission tube, spot size shall be less than or equal to 4 µm at 3 W power, 4 µm at 10 W power, and 6 µm at 20 W power

b. For a 225 kv dual transmission/reflection tube configuration, spot size shall be less than or equal to 4 µm at 3 W power, 4 µm at 10 W power, and 6 µm at 20 W power for transmission tube, and 3 µm at 3 W power, 10 µm at 10 W power, and 20 µm at 20 W power for reflection tube

c. For a 225 kv rotating target reflection tube, spot size shall be less than or equal to 10 µm at 3 W power, 10 µm at 10 W power, and 10 µm at 20 W power in rotating target configuration

d. For a 225 kv reflection (non-rotating target) tube, spot size shall be less than or equal to 10 µm at 10 W power, and 20 µm at 20 W power.

e. For a 240 kv reflection tube, spot size shall be less than or equal to 10 µm at 10 W power, and 20 µm at 20 W power Spot size may be estimated as two (2) times the JIMA resolution.

12. The x-ray tube and target shall be cooled using a chiller external to the cabinet.

13. The system shall have an amorphous-silicon digital flat panel detector.

14. The detector shall have a useable imaging area of at least 300 x 300 mm.

15. The detector shall have a pixel size of less than or equal to 150 m.

16. The detector shall have a minimum of 2500 x 2500 pixels.

17. The detector shall have 16-bit resolution.

18. The detector shall be capable of a minimum of 2.5 frames per second for a full resolution (unbinned) scan.

19. The system shall include a subsystem for maintaining temperature control of the internal cabinet environment which uses a fan to circulate air. (Stronger consideration will be given to systems in which the cabinet temperature is maintained with an independent system capable of heating and cooling the cabinet.)

20. The system shall include a radiation enclosure rated for the maximum x-ray voltage and power of the x-ray tube. Safety interlocks shall be present to ensure x-ray source cannot be turned on until radiation enclosure is in a configuration where x-rays are contained.

21. The radiation enclosure shall have at least one accessible cable access port to allow feed-through of NIST-owned sensors to the interior of the cabinet.

22. The system shall allow hardware integration of a Deben CT5000 load frame system, including cables and load frame structure, through 360 degrees of rotation. Free-rotation cable hardware (such as a slip ring) is not necessary.

23. The radiation enclosure shall have a window, of minimum 200 x 200 mm size, to allow the sample to be viewed during a CT scan.

24. The system shall include a Windows 10-based computer (or computers) with hardware and software sufficient for acquiring, reconstructing, and evaluating a full-resolution (2500 x 2500 pixels minimum) scan consisting of at least [maximum # of pixels in either direction x 1.5] radiographs using the provided software. For example, this would be 3750 radiographs for a 2500 x 2500 pixel detector.

25. The system shall include a monitor for each computer.

26. The maximum required power shall not exceed 220 v AC 3-phase at 60 Hz.

27. The system shall not require air above 90 psi (620 kPa).

28. The system shall fit through 2.16 m (85") tall opening (can be in disassembled state) in order to get into the laboratory. The maximum cabinet width shall not exceed 1.8 m.

Software

29. The system shall be able to capture and export a single digital radiograph in a standard (non-proprietary) image format.

30. The system shall be able to acquire and reconstruct CT scans with circular and helical scan trajectories. (Stronger consideration will be given for ability to acquire and reconstruct additional trajectories such as offset scanning and multiple extended field of view scanning.)

31. The system shall have the ability export each corrected radiograph of a CT scan (if radiographs are corrected prior to reconstruction) in a standard (non-proprietary) image format. (Stronger consideration will be given to systems that also allow the export of uncorrected radiographs and the bad pixel map in a standard image format.)

32. The system shall have the ability to reconstruct any given set of images (simulated or otherwise externally generated) provided they represent a CT scan trajectory and system geometry that are within the scope of operation for the system. Any information or formatting required by the system to perform this reconstruction, such as image file format and system geometry description, shall be clearly and completely defined so that the appropriate files can be generated by NIST.

33. The reconstruction software shall have, at a minimum, the ability to reconstruct volumes using a filtered backprojection reconstruction algorithm. The vendor shall provide an explanation of the reconstruction process to include the type/size of reconstruction filter and window applied for filtered backprojection algorithm, the relationship between reconstructed image intensity (float, 16-bit, and 8-bit) to attenuation coefficient, and image rescaling process from float to 16/8-bit images. If special acquisition and reconstruction process is applied, suitable explanation shall be provided.

a. (Stronger consideration will be given if the system can also reconstruct using iterative reconstruction methods.)

b. (Stronger consideration will be given to the software allowing the change of FDK reconstruction filter type and size for the filtered backprojection algorithm.)

c. (Stronger consideration will be given for software that allows reconstructed image intensity relatable to physical attenuation value and allowing custom rescaling of reconstructed image intensity from float to 16/8-bit images.)

34. Software shall be provided which can perform the following radiograph processing functions: noise reduction which the user may choose to apply, bad pixel correction, offset subtraction, and intensity (gain) correction. If multiple gain images are acquired, suitable gain correction algorithm should be implemented, and details of the process shall be made available.

35. Software shall be provided which can perform the following functions: beam hardening correction, ring artifact reduction, and region of interest reconstruction.

a. (Stronger consideration will be given for systems capable of focal spot drift correction.)

b. (Stronger considerations will be given to a system incorporating hardware-based ring artifact removal process (e.g., fine movement of detector or sample stages)

36. The system shall include software for the analysis and visualization of voxel data which has the following capabilities: surface extraction to a cloud of 3D coordinates (point cloud); manual and semi-automated segmentation tools for the separation of materials and geometry within one data set; subvoxel surface determination with automatic, manual, and interval-based options; geometry element fitting; geometric comparison of voxel, mesh and CAD data; and automated wall thickness analysis.

37. Hardware and/or software access shall be provided to allow NIST to control all axes of motion (to include read-out of encoder position and motor control) so that the user can define and automate trajectories using any combination of axes of motion. This motion shall be able to be integrated with radiograph capture, third party hardware (such as a laser interferometer), and third-party analysis software. (Stronger consideration will be given for systems that provide scripting software which allows NIST to achieve this level of control and integration.)

38. NIST shall be provided access to view and edit all system geometry parameters that are used during the reconstruction process. File structure and formatting shall be clearly and completely defined so that the appropriate files can be generated by NIST.

39. NIST shall be provided with software, reference artifacts, and access to perform, at any time before and/or after a CT scan, calibration of the system geometry parameters that are used by the reconstruction process.

Other Specifications

40. A spare parts kit for the X-ray tube, including a minimum of two (2) filaments, shall be included.

41. A prefilter kit consisting of at least six (6) prefilters of different thicknesses and/or materials, shall be included.

42. Sufficient information (e.g. 2-D CAD drawings in pdf format) to enable design and construction of mounting fixtures for parts and for the interferometer optics used for error mapping shall be provided to NIST for the detector mount, rotary table, and source mount shall be provided to NIST upon award.

43. Restrictions that affect NISTs ability to publish CT data (including radiographs, reconstructed volumes and surface coordinates) and research findings are not acceptable.

Performance

44. In order to show the performance of the system meets overall requirements, artifact testing for two items will be required as part of the solicitations evaluation criteria and inspection and acceptance per below.

CLIN 0002: The Contractor shall provide one (1) year of maintenance to commence after the acceptance that meets the following minimum requirements:

1. Check and test all parts and mechanical and electrical systems functionality.

2. Clean all parts, replace with spare parts where and when needed. If additional replacement parts outside the scope of work for the above tasks is needed the Contractor shall contact the Contracting Officer for approval prior to installing the additional parts.

3. Update system software to newest version if available at time of service.

4. Provide certification showing that system meet original manufacturer’s specifications.

5. One (1) visit per period of performance.

IV. Site Preparation

NIST will prepare the laboratory for the XCT system prior to installation.

V. Delivery

Delivery shall be FOB Destination (or equivalent terms, such as INCOTERMS Delivered Duties Paid) are required and shall occur not later than (NLT) twenty-eight (28) weeks ARO.

FOB Destination means: The contractor shall pack and mark the shipment in conformance with carrier requirements, deliver the shipment in good order and condition to the point of delivery specified in the purchase order, be responsible for any loss of and/or damage to the goods occurring before receipt and acceptance of the shipment by the consignee at the delivery point specified in the purchase order; and pay all charges to the specified point of delivery. The contractor shall deliver all Line Items to:

The National Institute of Standards and Technology 100 Bureau Drive, Building 219 Gaithersburg, MD 20899

VI. Inspection and Acceptance

In addition to the inspection and acceptance terms articulated in 52.212-4, the Government reserves the right to perform such performance tests and evaluations as defined below to verify specified system performance. Such tests and evaluations, if performed, shall be conducted within the environment that the system is to be operated. The Contractor has the right to be present during the tests and evaluations, if performed, at the Contractor’s expense.

The measurements requested of the Contractor during the procurement process will be repeated using objects of the same nominal sizes and materials. It is expected that the system produces similar results for both Artifact A and Artifact B. Specifically for Artifact A, it is expected that for the maximum errors in center-to-center length, size, and form be no greater than 125% of the errors in the values submitted or the optional manufacturer supplied specifications, whichever is greater. It is also expected that for Artifact A the image acquisition time for each scan, reconstruction time for each scan, and first to last (repetition of first) image movement be no greater than 125% of the values submitted. For Artifact B, it is expected that for the total image unsharpness value at the central plane (1/MTF10) be no greater than 125% of the total image unsharpness value (1/MTF10) submitted. It is also expected that for Artifact B the image acquisition time for each scan, and reconstruction time for each scan be no greater than 125% of the values submitted.

The Government will test, inspect, and accept the equipment onsite within 15 business days of the completion of installation and training of the XCT system. A visual inspection of the XCT system will be performed by the NIST TPOC to identify surface defects or any form of indication that the XCT system was damaged during transport to NIST. The Government will have sole discretion to require repair or replacement of damaged and/or nonconforming supplies at no cost to the Government. The Government, at any time prior to acceptance, may reject the XCT system due to defects and/or nonconformance.

VII. Installation

The system shall be installed by the Contractor no later than one (1) month after delivery, unless otherwise agreed to by NIST and the Contractor. Installation, at a minimum, shall include uncrating/unpackaging of all equipment, set-up and hook-up of the system, demonstration of all specifications, and removal of trash. Rigging does not need to be included. Onsite installation and demonstration shall be done at NIST, Gaithersburg, MD- Building 219.

VIII. Training

The Contractor shall conduct a minimum 3-day training session for up to five (5) users at NIST. The training shall provide a thorough demonstration of all system functions, maintenance, data administration, and basic troubleshooting. The training may be completed at NIST immediately after installation/set-up and on-site measurements demonstrating that no damage or misalignment issues arose during transportation and installation but shall be completed no later than 1 month after installation, unless otherwise agreed to by NIST and the Contractor.

IX. Warranty

The Contractor shall warrant the entire system for a period of a minimum of 1 year after receipt of the equipment and shall be in accordance with terms in FAR 52.212-4.

X. Payment Schedule

The Contractor shall be paid, in accordance with Net 30-day payment terms, upon receipt and acceptance of a proper invoice. One lump sum payment will be authorized upon the Contractor’s completion of delivery, installation, training, and NIST’s acceptance.

Note: Offerors may propose an alternate payment schedule in its quotation submission for the Government’s consideration.