Technical Exhibit 2 Cryrocooler System.docx

TECHNICAL EXHIBIT 2

CRYROCOOLER SYSTEM with Integrated IR Detectors

Technical Parameters for two small cryocooler(s) systems including custom Dewar and mounting flange:

1. Compressor/pump is <=1.8” Diameter by <=4.73.5” long,

2. The envelope for the cold head is <=.93” diameter (not including a heatsink) by <= 1.4” tall (not including a heatsink) and the cold finger Dewar protrudes about 1.5” from the mounting base and contains a 25mm diameter Germanium filter window.

3. The detectors on the cold tip must be at the focal point of the focusing mirror in the RS-25 line scanner, and the top side of the cold head should be within about 2.4” of the RS-25 scan head top surface. The additional inch within this 2.4” height above scan head measurement is to allow space for SMA, temperature, and vacuum port connectors. The goal is to minimize the overall height of the scan head assembly. These size limitations are due to space limitations in the airborne environment where the cryocoolers will be operated.

4. A split cryocooler system is necessary and provides for reduced risk of vibrations and electromagnetic interference (EMI) affecting the MCT IR detector signal output, and keeps overall scan head assembly height at a minimum.

5. Government provided detector pairs are removed from the government furnished LN2 Dewars onto the cold finger of a new cryocooler system (Contractor provided). Basically, the dual MCT detector pair is .165mm square each and spaced .889mm apart on a center line from Starboard to Port. Please see document “Forest Service cryocooler for detector, Item 1 image on page 7”.

The Forest service recognizes a small level of risk to remove and relocate the MCT detector pair with dual band filters, so new Teledyne/Judson detectors may be required if the relocation of government furnished detectors fails. If the relocation of existing MCT detector pairs is not successful, the Contractor and Technical Manager will coordinate the option for the Contractor to procure and install identical detectors (CLIN 0002) as contained within the Teledyne/Judson Technologies model# J15D12-M360-S165U-58-CF2:2E, Part# 453169 and deliver the new integrated cryocooled detector assemblies to the Forest Service. If new detectors are required additional time to acquire the parts is acknowledged.

Alternative: If it is not technically possible to mount identical detector pairs in their current formfactor, direct bonding of the detector pairs to the cold finger could be an option if the Technical Manager agrees this is the best course of action. Direct bonded detector pairs will have to conform to the electronic performance, and physical size, and spacing profile, as outlined in this document and Technical Exhibits 1, 4, and 5. Direct bonded detectors will also have identical performance and active area sizing and spacing as the detectors supplied with the Teledyne/Judson Technologies model# J15D12-M360-S165U-58-CF2:2E, Part# 453169, but the mounting substrate disk can be omitted. Additionally if direct bonded detectors are used the resealable vacuum port and dewar gasket seals can be omitted.

6. The MCT IR detectors currently used by the USFS are mounted on a 1/2” cold finger within a LN2 Dewar. The detectors and IR cold filters (3-5um & 8-12um) are attached to the cold finger with 2 screws each and are accessible via several additional screws that permit separating the vacuum portion of the Dewar. The detector is a dual band so there are four solder posts, two conductors for each detector with roughly 30ga wire connecting each detector to an isolated SMA connector on the Dewar body. Please see document “Forest Service cryocooler for detector, Item 1 image on page 7”.

7. The current detectors are covered by a dual cold filter assembly that is secured to the detector with two screws (reference Item 1). The RS-25 line scanner motor is mounted on the aft side of the scanner. The detectors are oriented in-line Starboard (Right) to Port (Left). The 8-12 um detector (Chan B) is oriented nearest the Starboard side and the 3-5um detector (Chan A) is oriented nearest the Port side (Left). The detector substrate is secured with two #0-80 THD screws to the end of a ½’ cold finger. The #0-80 THD screws are oriented perpendicular to a line drawn through the MCT detector centers. These screws can be seen in the “Item 1” image but they are partially obscured by the IR filter window assembly. The 0-80 THD screws are on a .375” bolt circle diameter. The detector is mounted looking downward. The best space for the cryocooler compressor/pump is beside the cold head on top of the RS-25 scan head, and to the Starboard or aft sides of the cold head assembly.

8. The Image labeled “Item 2 on page 8 in the document “Forest Service cryocooler for detector” shows the Starboard and aft sides of the scan head with rulers to give some perspective of the available space for alternate compressor/motor mounting locations.

9. The images labeled Items 2 and items 3.A through 3.K in the document “Forest Service cryocooler for detector” are associated with our King Air B200 aircraft and show the area and obstructions with the scan head mounted on the aircraft. The King Air B200 system is in a pod under the belly of the aircraft.

10. The images labeled item 4.A through 4.E in the document “Forest Service cryocooler for detector” are associated with our Citation Bravo and show the area and obstructions with the scan head mounted in the aircraft. The Citation Bravo system is in a scanner well (box) that is built into the cabin space, but it is outside of the pressure vessel.

11. A SolidWorks 3D model of the RS-25 scanner assembly is available after a signed NDA agreement is secured.

12. Provide a method to precisely position the cryocooled detector assembly on the scan head in the X, Y, and Z directions such that the detector sensors can be positioned at the focal point of the scanner. Using brass shims is acceptable for Z, and X & Y can be accomplished by following the mechanical design of the Kadel Engineering Corp Dewar mounting flange. The mounting flange bolt holes are .189” diameter, 6 places, on a 3.625” B.C.D.. Note: If the gas tube between the compressor/motor and the cold head of the cryocooler is rigid, then the compressor/motor will have to move with the cold head and move within the compressor/motor mount when precision positioning the cold head at the scanner focal spot.

13. A flexible transfer line from the compressor/motor to the expander (cold head) is desired for greatest ease of positioning the cold head and mounting of the compressor.

14. Two each dual band MCT infrared detector pairs mated (removable) to the cold finger of either the Thales LSF-9997 or the AIM SF-070 split linear cryocoolers utilizing a “flexure bearing compressor” (necessary for reduced vibrations) and has a minimum time to failure (MTTF) of >=20,000 hrs, or equivalent as described in these cryocooler manufacturers descriptions and the requirements in this document. These two cryocooler models are two designs believed to meet the size and performance requirements for this application.

15. Cryocooler must be; off the shelf available, recommended for new designs (i.e. not a near end of life product), and have a minimum mean time to failure (MTTF) >= 20,000 hours.

16. Provide a custom vacuum Dewar encasing the detectors and cold finger with an integrated wideband IR filter, mounting flange, connectors, and vacuum port.

17. The required minimum lift is a little less than 5mW. This is the power of the detectors self-heating due to bias currents.

18. The cryocooler must chill the detector pair to about 77 Kelvin for a minimum operating range of ambient temperatures from -40C to 60C.

19. The vendor will provide a chart of the cold finger tip temperature attainable by the proposed cryocooler with the MCT detectors mounted and powered for a range of ambient temperatures of -40 Centigrade to 60 Centigrade.

20. Two complete cryocooler systems are required and each will come with the cryocooler control electronics. Both systems must be able to automatically run to the set-point upon main power-up, such that the initial configuration and or set points are saved or preserved in such a way that no subsequent setup is necessary after main power-off/power-on cycling.

21. The cryocooler controller can have an alert signal output (logic or serial data) in case of cryocooler system malfunction so long as the communication line is normally quiet.

22. Under normal operation there will not be any serial data present on any transmission line between the computer in the pressure vessel and the cryocooler system outside of the pressure vessel. This is to eliminate any chance of signal cross coupling into the low level analog signal path. All noise in the analog signal path is visible in our fire map images.

23. The cryocooler must be operable from sea level to 28,000 feet above sea level. The cryocooler will be operated in an airborne environment, and it will live outside of the pressure vessel (i.e. not conditioned space) on aircraft.

24. Being that the cryocooler is in an airborne environment, the cryocooler must also be survivable from 28,000 feet to 45,000 feet above sea level.

25. Cryocooler and cryocooler controller must be IP65 water resistant or better over the temperature range -40C to 60C, and altitude operating range MSL (mean sea level) to 45,000 feet AMSL (above mean sea level).

26. The time to chilled equilibrium can be 10 to 20 minutes but should reach 80% (113K) of 77K within about 10 minutes.

27. Cryocooler bodies, controller, and detectors (Dewar) will be shielded and have a mechanical and electrical (not anodized) ground bonding point to minimize RFI/EMI emissions to reduce electronic noise coupling in the detectors output signal.

28. Cryocooler compressor/motor will have a mechanical dampening method to eliminate or reduce high and or low frequency vibrations. The RS-25 line scanner has a fast f2 mirror which make its focal point susceptible to seeing detector vibrations.

29. The main detector window containing the vacuum for the cold finger and detectors will be 25mm diameter by 1mm thick, 3-12um broad band Germanium with an antireflective coating such as Edmund Optic part number 83-349. The detectors will be centered on this window and sit .625” behind the outer surface of this window in order to maintain the current view cone, field of view. This diameter is needed to maintain a field of view (FOV) that is nominally 48.9Deg when viewed perpendicular to the sweep track across the detectors, and nominally 58.7Deg when viewed parallel to the sweep track across the detectors.

30. The mounting flange with Bolt Circle Diameter (BCD), and cold finger detector BCD mounting holes will conform to the mechanical layout of the Kadel Engineering Corp’s model KR360.

31. The mechanical outline and dimensions between the wideband Germanium window, the mounting flange, and the detector mounting position on the end of the cold finger will conform to the measured relationships as shown on the Kadel Engineering Corp KR360, and the Teledyne Judson model# J15D12-M360-S165U-58-CF2:2E, Part# 453169 drawings.

32. The center of the detector pair shall be centered on the cold finger, and the detector pair shall be centered within the 4 inch mounting flange diameter to within a circle of radius .002828 inch. (This is to facilitate mating the cryocooled detectors at the focal center by utilizing clearance between mounting screws and the mounting flange holes on the 3.625 bolt circle diameter (BCD).

33. Two output connectors, one for each detector will be isolated SMA connectors.

34. Provide a resealable Vacuum port similar to the ¼” insert valve on the Teledyne Judson Technologies model# J15D12-M360-S165U-58-CF2:2E. This is a Kadel Engineering Corp KR360 Dewar. The vacuum port is a re-sealable Cryolab SV8-082 (1/4”) Series or similar.

35. Provide Part number for the appropriate vacuum valve operator.

36. The dewar will be re-sealable to provide a method to access the removable cold filter and detector pair. The cryocooler Dewar will be separable via machine screws. (i.e. not a welded and pinched off vacuum chamber for the detectors).

37. The cold head, cold finger/detector assembly must be able to mechanically fit and mount on top of the RS-25 line scanner with the detectors at the focal point and in the proper orientation as described above and here, 8-12um on the Starboard side and 3-5um on the Port side, and while minimizing the overall height of the RS-25 scanner with the cryocooler mounted.

38. Provide 2 each spare gaskets suitable for resealing the Dewar hermetic seal.

39. The Detectors and cold filter pair will be attached with #0-80 THD machine screws to the cold finger, and specify the screw material (i.e. stainless, brass etc.) and maximum tightening torque for these screws. Specify any bonding agents and or thermally conductive product used to secure the detector pair to the cold finger.

40. The RS-25 line scanner motor is mounted on the aft side of the scanner. The detectors must be oriented in-line Starboard (Right) to Port (Left). The 8-12 um detector (Chan B) is oriented nearest the Starboard side and the 3-5um detector (Chan A) is oriented nearest the Port side (Left). The detector substrate is secured with two #0-80 THD screws to the end of a ½’ cold finger. The #0-80 THD screws are oriented perpendicular to a line drawn between the MCT detectors. These screws can be seen in the image in document “Forest Service cryocooler for detector”, “Item 1”, but they are partially obscured by the IR cold filter window frame assembly. The 0-80 THD screws are on a .375” bolt circle diameter. The Image in document “Forest Service cryocooler for detector”, “Item 2” shows the Starboard and aft sides of the scan head with rulers to give some perspective of the space where the detector is mounted and space for the cryocooler compressor.

41. The mounted detectors will be presented looking straight downward. The best space for the cryocooler compressor/pump is on the Starboard or aft sides. We currently have an INS navigation system mounted on the front side and a defrost heater assembly mounted on the Port side.

42. The inside and outside of the tube containing the vacuum area of the cold finger and detector must be prepared with a low reflectance surface and employ a baffle washer that encroaches on the view cone but does not block it, to reduce secondary reflections within the vacuum area of the tube containing the detectors. The only exception to the dewar containment tube having a low reflectance surface is the gasket area that makes a vacuum seal to the cold head. The USFS has a solid model example of this part currently in use. The surface was prepared by lightly sandblasting the surface using Brown Aluminum Oxide, type A, Grit 120 from K-Deer LA, Inc, followed by hard anodizing black. Through rinsing is required between and after anodizing cycles to prevent outgassing of anodizing process chemicals when put under vacuum in the Dewar. This resulted in a relatively flat black surface which has proved to function as prescribed since the beginning of June 2019.

43. Cryocooler and controller must operate off a mains power of 28VDC. 28VDC is the main power source in the aircraft.

44. Each cryocooler system must be serialized and identify which Teledyne Judson MCT detector pair is contained within each serial numbered cryocooler.

45. Provide cryocooler datasheet and model/part number information.

46. Provide cryocooler system warranty period and method of execution information.

47. Vendor to provide all drawings and or solid model files of the cryocooler parts and assembly if they exist or are generated for this project, and if new detectors are bought, then a legible measured 2D drawing(s) and or 3D solid model file(s) of the detectors, substrate, and cold filters (i.e. engineering drawings) is required. A shrink to fit partially legible 2D .pdf printed on a 8.5” x 11” sheet of paper is not acceptable.

48. Provide all controller technical data, configuration information, and saved configuration files.

49. Provide operation narratives and technical drawings and or solid model files of custom parts.

50. Provide narratives and or technical data for any modifications or deviations to the off the shelf cryocooler.

51. State the type and pressure of gas used in the cryocooler system.

52. The vendor and USFS will share mechanical drawings and or solid model files and work together to determine the best methods to mount cryocooler and cold head/finger/detector.