Low-temperature analysis assembly and low-temperature analysis method

Abstract

Cryogenic analysis assemblies and methods are provided. These assemblies and / or methods may be configured for optical sample analysis. These assemblies and / or methods may include an objective lens assembly operably aligned with a sample support assembly, both the objective lens assembly and the sample support assembly being present within a vacuum housing; wherein the objective lens assembly defines an objective lens support housing an objective lens, the objective lens support coupled to a mounting ring within the chamber below the heater assembly; and an isolation member between the objective lens holder and the mounting ring, the isolation member supporting the objective lens holder and thermally isolating the objective lens holder from the mounting ring.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a continuation-in-part of U.S. patent application serial number 14 / 666,093 filed on March 23, 2015, which claims priority to and the benefit of U.S. provisional patent application serial number 61 / 968,651 filed on March 21, 2014, each of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to cryogenic analysis assemblies and cryogenic analysis methods. In certain embodiments, the present disclosure relates to assemblies and methods that include using a microscope objective during cryogenic analysis. Background Art

[0004] Many cryogenic researchers use optical microscopy to study single molecules. This is accomplished by using a microscope objective to focus and / or collect light from a sample held at cryogenic temperatures. Microscope objectives are precision-made chains of lenses that can only be used at room temperature. High light collection efficiency also requires that the objective have a very small working distance between its end and the sample. Researchers have historically traded objective performance for a longer working distance to allow the objective to be mounted outside the cryostat.

[0005] The present disclosure provides cryogenic analysis assemblies and cryogenic analysis methods, embodiments of which overcome one or more disadvantages of prior art cryogenic analysis assemblies and methods, particularly those cryogenic analysis assemblies and methods using microscope objectives. Summary of the invention

[0006] Cryogenic analysis assemblies and methods are provided. The assemblies and / or methods may be configured for optical sample analysis. The assemblies and / or methods may include: an objective lens assembly operably aligned with a sample support assembly, both of which are present within a vacuum housing; wherein the objective lens assembly defines an objective lens holder that houses the objective lens, the objective lens holder coupled to a mounting ring within a chamber below a heater assembly; and an insulating member between the objective lens holder and the mounting ring, the insulating member supporting the objective lens holder and thermally isolating the objective lens holder from the mounting ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Embodiments of the present disclosure are described below with reference to the following drawings.

[0008] Figure 1 is a part of a cryogenic analysis assembly according to an embodiment.

[0009] Figure 2 is another configuration of a portion of a cryogenic analysis assembly according to an embodiment of the present disclosure.

[0010] Figure 3 A low temperature analysis component according to an embodiment of the present disclosure.

[0011] Figure 4 According to an embodiment of the present disclosure Figure 3 Exploded view of the cryogenic analysis components.

[0012] Figure 5 FIG. 1 is a diagram showing an embodiment of the present disclosure. Figure 3 Part of the cryogenic analysis assembly.

[0013] Figure 6 An isometric cross-sectional view of a portion of a cryogenic analysis assembly according to an embodiment of the present disclosure is shown.

[0014] Figure 7 According to an embodiment of the present disclosure Figure 3 Drawing of the cryogenic analysis components.

[0015] Figure 8 Components of a cryogenic analysis assembly according to one embodiment of the present disclosure are shown.

[0016] Fig. 9 More components of a cryogenic analysis assembly according to an embodiment of the present disclosure are shown.

[0017] Fig.10 An exploded view of components of a cryogenic analysis assembly according to one embodiment of the present disclosure is shown.

[0018] Fig.11 FIG. 1 is a diagram showing an embodiment of the present disclosure. Fig.10 A cutaway isometric view of a component.

[0019] Fig.12 FIG. 1 is a diagram showing an embodiment of the present disclosure. Figure 7 Part of the cryogenic analysis assembly.

[0020] Fig.13 More components of a cryogenic analysis assembly according to an embodiment of the present disclosure are shown.

[0021] Fig.14 FIG. 1 is a diagram showing an embodiment of the present disclosure. Figure 7 Part of the cryogenic analysis assembly.

[0022] Fig.15 More components of a cryogenic analysis assembly according to an embodiment of the present disclosure are shown. DETAILED DESCRIPTION

[0023] Applicants have recognised that prior art techniques for longer working distances use windows placed between the objective and the sample and that these windows can introduce aberrations.

[0024] Applicants have also recognized that using a microscope for extended periods of time can cause thermal drift associated with room temperature fluctuations. When the mount holding the objective warms or cools, its material expands or contracts, causing the objective to come in and out of focus on the sample.

[0025] Mechanical vibrations also present problems for researchers. Applicants have recognized that fragile mounts can cause the objective to move relative to the sample beyond its optical resolution.

[0026] The present disclosure provides the following assembly and method: it can maintain an object (objective lens) at an elevated temperature while mechanically aligning the object (objective lens) with a sample inside a cryogenic system. Using the assembly and method of the present disclosure, this can be achieved through the interaction of three components: a cryogenic base, a thermal insulation support, a heater, and a thermometer. The present assembly can interface a microscope objective lens with a working distance greater than zero to image samples between 0K and 350K, and the window interface does not cause aberrations.

[0027] In addition to its primary purpose of connecting an objective interface at room temperature to a cryogenic atmosphere by isolating the heat load, this device can also be maintained at a very precise temperature, accurate to <10mK, which enables a virtually thermal drift-free environment to provide optical stability.

[0028] Reference Figure 1-Figure 15 The components and methods of the present disclosure are further described. Figure 1 , shows a portion of a cryogenic analysis assembly 10 according to an embodiment of the present disclosure, which includes an objective lens 12 and a sample 14 on a sample support 16. According to an exemplary embodiment, Figure 1 An objective 12 is depicted in operable alignment with a sample 14 within a cryogenic assembly. The objective 12 may be a set of optics and / or lenses that may or may not be bundled, but configured to provide a field of view of the sample 14 in operable alignment therewith. The sample 14 may be a solid sample, and the sample support 16 may be configured to support the sample 14 in operable viewing alignment with the objective 12, and to be cooled or heated.

[0029] Objective lens 12 may be maintained at a temperature that is different from the temperature of its surroundings. For example, the temperature of objective lens 12 may be different from the temperature of the sample and / or sample support. The temperature of objective lens 12 and / or the optics and / or lenses and / or lens surfaces of objective lens 12 may differ from that of sample 14 and / or sample support assembly 16 by at least 250K and / or at least 100K. Sample 14 and / or sample support assembly 16 may be maintained at a temperature below about 200K, and in some embodiments, below 40K and / or about 4K. According to one embodiment of the present disclosure, at Figure 2 and Figure 3The objective lens assembly 200 of the low temperature analysis assembly is provided in the present invention. The assembly 200 may include the objective lens 12 and the objective lens holder 50, to which the objective lens 12 may be mounted. The assembly 200 may also include a mounting ring 202 to operably align the objective lens assembly 200 with the sample 14. The mounting ring 202 may be attached to the sample support assembly 16 or the radiation shield 28 via screws or other mechanisms. The mounting ring 202 may be attached to a component at a cryogenic temperature. The objective lens assembly 200 may also include a thermal insulation support 95 between the objective lens holder 50 and the mounting ring 202 to facilitate the objective lens holder 50 and the mounting ring 202 to have different temperatures. The objective lens assembly 200 may also include a thermal control or heater assembly 24, which may be controlled to, for example, maintain the objective lens 12 at room temperature. For example, to protect the sample 14 from the influence of the thermal radiation load of the room temperature objective lens 12, the objective lens assembly 200 may also include a radiation shield 203 mounted to the mounting ring 202. The radiation shield 203 may also include a small aperture or window 204 to allow the objective 12 to observe the sample 14 .

[0030] The objective lens holder 50 is also shown in Figure 2 and the objective lens 12 can be adjusted closer to and further away from the sample 14, such as Figure 3 In addition, the objective lens mount 50 can enable lateral movement of the objective lens 12 relative to the sample 14. The objective lens mount 50 can enable indicating the position / distance relative to the sample support assembly 16. The objective lens mount 50 can be configured to integrate different objective lenses 12, different form factors and / or different optical properties.

[0031] Figure 2 Also depicted is an optional removable alignment reference 350 that enables simplified positioning / focusing of objective 12. Alignment reference 350 may be configured for different free working distances of objective 12.

[0032] refer to Figure 3 and Figure 4, depicting a cryogenic analysis assembly 20 in both a cross-sectional view and an exploded view, which includes an objective lens assembly 200, which is configured to operably align the objective lens 12 with the sample 14 in the sample support assembly 16. The assembly 20 may include a sample support assembly 16 that physically supports the sample. The assembly 20 may include a vacuum housing 26 and a vacuum housing cover 22, which may be maintained at room temperature. A shield 28 may surround the sample 14 and be within the housing 26, and the shield 28 may be configured to reduce radiation transmission between the sample 14 and the housing 26. The shield 28 may, for example, prevent 40K radiation from being transmitted to the housing 26 by isolating the sample 14 from the housing 26. The shield 28 may, for example, be constructed of aluminum. The positioner 29 may be piezoelectrically driven and present below the sample 14.

[0033] like Figure 3 and Figure 4 , the cryogenic assembly 20 includes an objective lens assembly 200 that is operably aligned with a sample shield 28 and a sample support assembly 16 within a vacuum housing 26. The objective lens assembly 200 can be configured to operably align the objective lens 12 with the sample 14. The vacuum housing 26 can include a housing viewing port 260. The assembly 20 can include a vacuum housing cover 22 that can be maintained at room temperature.

[0034] A sample radiation shield 28 can be between the objective lens assembly 200 and the sample support assembly 16, which can be operably aligned around the sample 14 and within the housing 26. The sample shield 28 can be configured to prevent radiation transmission between the sample 14 and the housing 26. The shield 28 can be constructed of a thermally conductive material (e.g., aluminum, copper) and also include a sample viewing port 280 that allows the sample 14 to be observed via ports 260 and 280 when the sample viewing ports are operably aligned. The shield 28 can be maintained at the same temperature as a portion of the sample support assembly (e.g., a first level of 40K). By maintaining the shield 28 at these lower temperatures, higher temperatures (such as those of portions of the objective lens assembly and / or housing 26) can be isolated from the sample 14. As part of the sample support assembly 16, the positioner 29 can be piezoelectrically driven and present below the sample 14.

[0035] Objective lens assembly 200 may also include a heater assembly 24 that can be controlled to maintain objective lens 12 at a predetermined temperature; for example, above mounting ring 202, radiation shield 203, sample radiation shield 28 (see, e.g., Figure 3), sample 14 and / or sample support assembly 16. As an example, heater assembly 24 may maintain support 50 and objective 12 and additional portions of objective assembly 200 at 300 K, while mounting ring 202, radiation shield 203, sample radiation shield 28 (see, e.g., Figure 3 ), the sample 14 and / or the sample support assembly 16 are maintained at or below 40 K. To protect the sample 14 from the thermal radiation load of the higher temperature objective lens 12, the objective lens assembly 200 includes a mounting ring 202 (see, e.g. Figure 3 ) of the radiation shield 203 (see, for example, Figure 3 ). The radiation shield 203 may also include an aperture or window 204 to allow the objective 12 to view the sample 14 unimpeded. According to an example embodiment, the mounting ring 202 and shield 203 may be thermally connected to the sample radiation shield 28 and maintained at 40 K or below. By providing a thermal environment around the optics 12 that maintains that temperature, optical drift is significantly reduced, which allows the user to place the optics at a working distance from the sample for an extended period of time without losing focus.

[0036] Next reference Figure 5 and Figure 6 ,exist Figure 5 , a portion of the assembly 20 is shown, which includes a vacuum housing 30 that may be at room temperature and a portion of the sample support assembly 16 that may be at cryogenic temperature. Figure 6 An isometric cross-sectional view of a portion of the assembly 16 is shown in . The sample support assembly 16 can include a first stage support ring 32 that can be 40K and a second stage support ring 34 that can be 4K. Therefore, this interface between the sample support assembly 16 and the vacuum housing 30 is configured to achieve efficient sample replacement by maintaining several parts of the sample support assembly at two different temperatures. The first stage support ring 32 can allow for the attachment of the radiation shield 28. The second stage support ring 34 can allow for the attachment of the sample. The first stage support ring 32 and the second stage support ring 34 can be physically connected to each other and to the vacuum housing 30 by means of an isolation member 201 to allow the first stage support ring 32, the second stage support ring 34 and the base housing 30 to be maintained at different temperatures, but still be sufficiently mechanically engaged to provide a vacuum.

[0037] As shown, the cryogenic analysis assembly 20 may include a base housing 30 that is coupled to the housing 26 and may be at room temperature. Also depicted is a portion of the sample support assembly 16 that may be at cryogenic temperatures (e.g., 40K and 4K). The sample support assembly 16 may include a first-stage support assembly 32 and a second-stage sample support assembly 34. These staged assemblies may be maintained at different temperatures, for example, the first stage is maintained at 40K and the second stage is maintained at 4K. According to an example embodiment, the sample radiation shield 28 may be thermally coupled to the first stage and thus maintained at the same temperature as the first stage (e.g., 40K). In addition, the first-stage support assembly 32 may protect the second-stage support assembly 34 from the thermal radiation of the base 30.

[0038] The first stage support assembly 32 may include a support ring 320 and a shield support 322. The support ring 320 and / or the shield support 322 may be maintained at 40K, for example. The shield support 322 may be surrounded by the insulation member 201. One of the insulation members may be operably engaged between the support 322 and the base support mounting ring 31. Another of the insulation members may be operably engaged between the support 322 and the second stage sample support assembly 34. The shield support 322 may be configured as a radiation shield to prevent radiative heat transfer between the insulation members 201.

[0039] The second stage sample support assembly 34 may include a ring 340 operably engaged with a sample support platform 342 and a sample support platform ring 344. The second stage sample support assembly 34 may be operably engaged with the first stage sample support assembly 32 via other insulating members 201. According to example embodiments, the first stage may be maintained at a higher temperature than the second stage. Components of the first stage at this higher temperature may serve to protect lower temperature components of the second stage from room temperature components of the housing or base of the assembly.

[0040] As an example, component 32 can be maintained at 40K, while component 34 can be maintained at 4K. Both support components 32 and 34 can be connected to a cold (e.g., cryogenic) source configured to provide at least two cooling temperatures. Wherein the first-stage support ring 320 is configured for attaching a radiation shield 28, which can be maintained at a temperature (e.g., 40K) that is lower than room temperature but higher than the temperature of the sample 14 (e.g., 4K). The second-stage support ring 340 can allow the sample 14 to be attached. The first-stage support ring 320 and the second-stage support ring 340 can be physically connected to each other and to the base shell 30 by means of an isolation member 201, so that the first-stage support ring 320, the second-stage support ring 340 and the base shell 30 can be maintained at different temperatures but still mechanically engaged. Next, refer to Figure 7 , another depiction of a cryogenic assembly 20 is shown having an objective lens 12 operably aligned with a sample 14 . Figure 7 include Fig.12 and Fig.14 Details of the portion shown in FIG.

[0041] refer to Figure 8 , showing a perspective view and a cross-sectional view of the shield 28. The shield 28 can be configured to support the objective lens assembly 200, for example, via internal threads. The mounting ring 202 has mounting holes configured to attach the objective lens assembly 200 to the top 281 of the radiation shield 28. Fig.10 and Fig.11 To further clarify the engagement, an exploded view and a perspective cutaway view of the objective lens assembly 200 are provided.

[0042] refer to Figure 9-11 , providing a detailed view of the objective lens assembly 200. The objective lens holder 50 can be configured to support and house the objective lens 12. The holder 50 can include a sleeve 52 defining an internal chamber 54. The objective lens 12 can be within the chamber 54. The objective lens 12 can be coupled to the sleeve 52 by an objective lens coupling device 56. The objective lens coupling device 56 can be configured to move the objective lens 12 between several positions in the chamber 54. Therefore, the objective lens 12 can be movable within the chamber 54 to focus on features of the sample 14. The objective lens holder housing 58 can surround the sleeve 52. The objective lens holder housing 58 can be configured as a thermal radiation shield that protects the objective lens from temperature fluctuations in the housing 26. The sleeve 52, the device 56, and the housing 58 can be mechanically coupled, but thermally isolated from the mounting ring 202 by the insulating member 95. Therefore, when the shield 28 is maintained at one temperature, the objective lens 12 can be maintained at another temperature. The mounting ring 202 has mounting holes to attach the objective lens assembly 200 to the top of the radiation shield 28.

[0043] A portion of the component 20 is Fig.12 , which is shown as a detailed view of the thermal control assembly 24, which is coupled to the objective lens holder 50 around a bezel 72, which may be coupled to the objective lens holder 50, for example, via a bolted connection. The objective lens holder 50 may be coupled to the thermal control assembly 24 (shown in Fig.13 76, which forms a housing for the circuit system 78. The heater assembly 24 may also include an inner section 79. The section 79 may be an electrical wire, such as a copper wire, that is wrapped inside the groove. This section may be pressed into the outer section. The heater assembly 24 may also include a heater ring 77 that may be held in place via the cap 76.

[0044] The heater assembly 24 can be configured to provide heat to form a warm zone of the lens holder by using a resistor element to provide thermal energy through a Joule heating method. A processing circuit system such as a proportional integral differential controller (PID) can be used to control the temperature to provide a stability of 2mK. As described, the heater assembly 24 can include five components: an inner section, a housing, a printed circuit board (PCB), a top cap, and a retaining ring. The wires wound around the inner section can be resistor elements. The inner section can be pressed into the housing. The processing circuit system in the form of a PCB can be installed on the top of the housing. The processing circuit system can include a thermistor, a connector, a conductive body for the resistor element connection, and a thermostat. The thermistor can be used in conjunction with a primary heater winding for PID control, and the thermostat is used to form a fail-safe backup device in conjunction with an uninterruptible power supply (UPS) and a secondary winding. A top cap 76 is installed on the top of the PCB and bolted to the housing to provide a firm thermal connection through a heater ring system. A retaining ring 79 is threadedly connected to the lens holder 50 to provide a firm thermal connection to the mounting area. The retaining ring may be captured between the top cap 76 and the inner section 77 .

[0045] Another part of the assembly 20 is Fig.14 Detailed view of the engagement of objective lens mount 50 within assembly 20 is shown in FIG. 1 . Insulation support 95 extends to mounting ring 202 at a point that can provide a surface for epoxy joint 94. Insulation support 95 can be a G10 (fiberglass, polyetheretherketone (PEEK) and / or Teflon) insulation. Threaded interface 96 can couple mounting base 97 of insulation assembly 91 to assembly 20. 98 is a threaded connection that allows retaining ring 99 to couple and / or engage with insulation member 203. According to Fig.15 , the objective lens assembly 200 may also include a radiation shield assembly 205. The radiation shield assembly 205 may also include a member 203, which may be a beryllium copper orifice having a thickness of approximately 100 microns. The member 203 may be transparent and / or define an opening so that the objective lens 12 receives emission from the sample and / or provides emission to the sample. According to an exemplary embodiment, the objective lens 12 may be configured to provide emission to the sample that may cause sample excitation; the objective lens 12 may also be configured to receive emission in the form of light to observe the sample. The member 203 may also be integrated as a part of the objective lens and / or optical device, for example. This isolation member may be between the retaining ring 99 and the base 97.

[0046] The radiation shield assembly 203 can be threaded onto the mounting ring 202 of the objective lens assembly 200. The radiation shield assembly 203 can include a mounting base, a thin perforated disk, and a retaining ring. The mounting base can maintain the temperature of the orifice to the temperature of the radiation shield. The small orifice on the thin disk limits the radiation from the warm zone to the sample stage to reduce the heating of the sample. Due to the thickness of 100 microns, the thin disk also achieves a short working distance, which is smaller than the working distance of the microscope objective. The retaining ring maintains the position of the perforated disk while also maintaining good thermal contact between the disk and the mounting base.

[0047] The objective lens assembly 200, radiation shield 28, and sample support assembly 16 can be configured to work independently and / or in conjunction to reduce vibrations between the objective lens 12 and the sample 14. The objective lens assembly 200 can provide most of the interface and provide most of the thermal isolation for the objective lens 14. The objective lens assembly 200 is connected to the shield 28 interface. The objective lens assembly 200 can provide thermal isolation by utilizing the thermal resistance of the insulating support 95 that connects the internally threaded lens tube to the radiation shield mount. The G10 insulating support 95 can add a large amount of thermal resistance to the system, allowing the internally threaded lens tube and the microscope objective to be maintained at a temperature of ~295K, while the 40K radiation shield mount can be maintained at ~40K. The objective lens assembly 200 also protects the microscope objective from cooling due to radiation loss by encasing the microscope objective with the internally threaded lens tube.

[0048] The radiation shield 28 can protect the sample from room temperature radiation while also providing a stable location for the objective lens assembly 200 to be mounted. The radiation shield can be rigidly mounted to the first stage ring 32 of the sample support 16, which is maintained at a temperature of 40K, with a temperature stability approaching 50mK. This in turn maintains the radiation shield at this temperature and stability. The radiation shield has windows that allow optical access from the side of the sample space, which allows freedom of imaging techniques.

[0049] The cryogenic assembly of the present disclosure may be operated using additional components of the cryogenic instrument described in U.S. Patent No. 8,746,008, which is incorporated herein by reference in its entirety. The operator may also use the Cryostation of Montana Instruments, Inc. Tm (Cryo-Optical Thermostat) (Montana Instruments, Bozeman, Montana) is used with the components of the present disclosure to observe samples using an objective lens. In particular, the present disclosure can utilize the cryogenic power of the cryogenic instrument via conduction to achieve temperatures as low as 4K. Conductively coupling specific portions and / or components of the cryogenic analysis system of the present disclosure and / or heating the coupled portions of the system can provide the temperatures of these components at the levels described herein.

[0050] In accordance with the statute, embodiments of the invention have been described using language more or less specific with respect to structural and methodological features. However, it is to be understood that the invention as a whole is not limited to the specific features and / or embodiments shown and / or described, since the disclosed embodiments include forms of implementing the invention.

Claims

1. A cryogenic analysis assembly configured for optical sample analysis, the assembly comprising: an objective lens assembly operably aligned with a sample support assembly, both of which are present within a vacuum housing; wherein the objective lens assembly defines an objective lens holder for supporting the objective lens, the objective lens holder being coupled to the mounting ring below the heater assembly; as well as An insulating member is provided between the objective lens holder and the mounting ring, the insulating member supporting the objective lens holder and thermally isolating the objective lens holder from the mounting ring.

2. The assembly of claim 1 further comprising a sample radiation shield operably engaged between the objective lens assembly and the sample support assembly.

3. The assembly of claim 2, wherein the sample radiation shield defines at least one opening configured to allow visual inspection of a sample within the cryogenic assembly.

4. The assembly of claim 1, wherein the sample support assembly further comprises a first stage support assembly operably aligned around a second stage sample support assembly, wherein a first isolation member engages the first stage support assembly with the second stage sample support assembly.

5. The assembly of claim 4, wherein the first stage support assembly includes a support ring engaged with a guard support.

6. The assembly of claim 5, further comprising a second insulating member between a base of the assembly and the first level support assembly.

7. The assembly of claim 4, wherein the first stage support assembly is thermally and operably engaged with a sample radiation shield aligned between the sample support assembly and the objective lens assembly.

8. The assembly of claim 1, wherein the objective lens assembly further comprises an objective lens coupled to a sleeve, wherein the objective lens and the sleeve are thermally engaged to be maintained at the same temperature.

9. An assembly according to claim 8, wherein the objective lens is movable between a plurality of positions within a chamber defined by the sleeve.

10. The assembly of claim 1, further comprising a housing surrounding the objective lens assembly and the sample support assembly.

11. The assembly of claim 10, wherein the housing defines a plurality of inlets configured to observe a sample within the assembly.

12. The assembly of claim 11, further comprising a sample radiation shield engaged between the objective lens assembly and the sample support assembly.

13. The assembly of claim 12, wherein the sample support assembly comprises a first level support and a second level sample support, the first level support and the second level sample support being separated by a sample support isolation member.

14. The assembly of claim 13, wherein the sample radiation shield is thermally bonded to the first stage support.

15. The assembly of claim 14, wherein the mounting ring is thermally coupled to the sample radiation shield and the first stage support.

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