JP3110456B2 - Rapidly cooled cryostat for large infrared focal plane arrays - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to an infrared detector assembly with improved performance,
More particularly, the present invention relates to an infrared detector assembly having an improved cryostat or cryostat for providing rapid cooling of a large-scale infrared focal plane array.

[0002]

[Prior art]

Infrared detectors are often used in connection with military equipment and night vision equipment for detecting electromagnetic radiation in the wavelength range of 4 to 16 micrometers. Many such devices are commonly referred to as focal plane arrays (FPAs) and operate at low temperatures (c
Since it has an infrared detector array that is generally most sensitive when operated at ryogenic temperatures, it requires a cooling device to create and maintain a low operating temperature.
Moreover, temperature fluctuations directly affect the sensitivity of the detector, resulting in undesirable electronic instability and electronic noise. Therefore, it is desirable to maintain the cooled detector at a constant temperature to eliminate instability and noise when operating the detector.

[0003] Generally, a cryogenic cooling system (cryogenic cooling system) is used.
The stem takes the form of a Joule-Thomson cryostat utilizing a conversion of a high pressure gas to a cryogenic liquid or a Stirling cryo engine with a closed cycle cooling system. The cooling device is used with a vacuum insulated dewar in which the electromagnetic wave detector array is located. The dewar is evacuated to remove the thermally conductive gas occupying the area surrounding the detector array, and possible heat losses due to convection and conduction are minimized. In addition, the evacuated dewar also prevents moisture from condensing on the detector array.

[0004] The dewar is cooled by placing the indented region of the dewar ("coldwell") in contact with the expansion chamber ("expander") of the cryogenic cooler. Typically, the expander is a cold end (cold en) supporting a pedestal (platform) in the focal plane.
d), ie, a cylindrical tube (cold finger) with a "heat sink" on which the detector array and related components are mounted. Alternatively, the dewar may be configured lacking cold fingers and the detector array may be mechanically directly supported by the focal plane pedestal.
In either case, thermal energy is removed from the detector array via a heat sink thermally conductively connected to the cryogenic cooling device.

[0005] Since the cryogenic cooling device is in thermal communication with the heat sink, the expansion of the high pressure gas (ie, argon, nitrogen) in the cold well absorbs thermal energy from the detector array, and the electronic components are most efficient. It can operate at temperature. Furthermore, it is desirable to simultaneously cool the cold shield surrounding the detector array to reduce electronic noise and improve background scenes.

To produce efficient conductive absorption of thermal energy from electromagnetic wave detector arrays and cold shields, the focal plane pedestal on which they are mounted is made of a material or material composition that possesses certain metallurgical properties. Need to be made. Ideally, these properties include high strength, high modulus and high thermal conductivity. In addition, the focal plane pedestal must have low thermal distortion characteristics to minimize premature detector failure.

[0007]

[Problems to be solved by the invention]

There are a number of design constraints that affect the design of the focal plane pedestal. Because the focal plane pedestal is a structural support member,
The pedestal must have sufficient bending stiffness to minimize the mechanical deflection of the electromagnetic wave detector. Such a need becomes particularly important where the infrared seeker assembly is used as part of a munitions system that experiences high levels of vibration and high levels of acceleration in the boost phase. Another important design parameter is the degree to which heat is transferred to the focal plane pedestal. More specifically, it is very important that the cooling time of the cold end component of the infrared detector array assembly mounted on the focal plane pedestal be less than or equal to a predetermined maximum predetermined time. Cooling time is a key design parameter, as infrared seekers are used in consumable ammunition and the target must often be confirmed shortly after (or shortly before) the ammunition is fired.

[0008] In most modern applications, large scale staring type hybrid focal plane arrays (F)
The use of PA) necessitates the use of a thicker focal plane pedestal or heat sink. Increasing the pedestal thickness improves the reliability of a good hybrid and reduces thermal fatigue associated with detector failure. Unfortunately, the use of a thick focal plane pedestal increases the joule loading of the device, and proportionally increases the cryostat cooling requirements. At present, infrared detectors using large area FPAs, silicon readout chips, and large cold seals can achieve a minimum cooling time of about 10 to 12 seconds with a conventional Joule-Thomson cryostat. It is possible. However, in most modern ammunition applications, a cooling time of about 5 seconds is defined as the maximum allowable duration.

[0009]

[Means for Solving the Problems]

In view of the above problems, it is an object of the present invention to provide an improved cryostat assembly featuring a rapid cooling capacity for cooling a relatively large area detector array. In accordance with the present invention, there is provided a dual Joule-Thomson cryostat assembly comprising two concentrically aligned cryostats located within a cold well of a detector assembly. Each of the cryostats is in communication with a source of high pressure gas released into the coldwell. The high-pressure gas is directed at the component to be cooled at a relatively high outflow rate to provide a relatively high film coefficient to maximize heat transfer. Both the inner and outer cryostats of the dual cryostat assembly are designed to deliver high pressure gas to the electromagnetic wave detector. Further, the inner cryostat sends high pressure gas to the outer cryostat to pre-cool the outer cryostat. The outer cryostat is also designed to deliver high pressure gas to cool the cold shield surrounding the detector.

[0010] Other advantages and advantages of the present invention will become apparent to one skilled in the art from a reading of the following examples and claims, taken in conjunction with the accompanying drawings.

[0011]

【Example】

The cooling capacity of a conventional Joule-Thomson cryostat cooler is directly related to the Joule load of the detector / Dur to be cooled and the maximum allowable cooling time. At present, the technical requirements for infrared detectors include large area detector arrays (FPAs) of at least about 80 K (Kelvin) and surrounding cold shields of at least about 200 K, The ability to cool within simultaneously is included. More specifically, technical requirements for military applications require that FPA and cold shield be operated at operating temperatures of 7
It is stipulated that cooling to 7 に K and 150 ゜ K is performed within about 5 seconds. As noted above, conventional Joule-Thomson cryostats are currently only able to cool the hybrid detector array and cold shield to a defined cold operating temperature in a minimum time of at least about 10 to 12 seconds. In addition, the increased thickness of the heat sink creates additional joule loading requirements that must be considered in the development of a cooling system that can provide the desired rapid cooling rate.

Although it is known to use a dual cryostat assembly consisting of an inner cryostat and an outer cryostat, in the past the inner cryostat was primarily used for pre-cooling the outer cryostat. A relatively small portion of the inner cryostat cooling capacity is thermally conductively coupled to the FPA via the outer cryostat end cap. Traditionally, cooling to cool the heat sink, cold shield, and focal plane array (FPA) was primarily provided by an outer cryostat.

Referring to the drawings, there is shown a rapid cooling cryostat or cryostat assembly 10 according to an exemplary embodiment of the present invention. FIG. 1 shows a rapid cooling cryostat assembly.
Infrared seeker (seeker) 10 effectively arranged inside
1 shows a detector assembly 12, such as an assembly. Detector assembly 12
Is secured to the support structure by a plurality of fasteners (not shown) extending through holes 14 in mounting flange 16. A dewar housing 18 seals the front end of the detector assembly 12 and has a central opening 20 covered by an infrared window 22. The window 22 is made, preferably from germanium or zinc selenide, to produce the desired transmission band and is used to transmit incident infrared radiation to the detector. Deer housing 18
A getter 24 is provided to absorb the outgassed gas leaking into an internal cavity 25 inside the interior.

The detector assembly 12 includes a detector 26 that receives the infrared radiation and generates a response electrical signal. Preferably, the sensing device or detector 26 comprises a photoelectric sensing element focal plane array 28 that is electrically interconnected to the integrated circuit readout board 30. The hybrid detector 26 is secured to the “heat sink” or focal plane pedestal 32 by a thermally conductive adhesive, thereby allowing advection of thermal energy from the detector 26. Preferably, the adhesive compound is of a silicon-based, room temperature, vulcanized type having a low glass transition temperature and suppresses thermal stress. The focal plane pedestal 32 is a low-distortion member adjusted to maintain the flatness of the surface in a low-temperature cooling state in order to increase hybrid reliability. A typical illustration of an enhanced focal plane pedestal 32 to enhance good hybrid reliability is assigned to the common assignee of the present invention.
U.S. Patent Application No. 07 / 397,808 filed August 23, 1989,
"LOW DISTORTION FOCAL PLANE P
LATFORM) ", the entire disclosure of which is expressly incorporated herein by reference. In this way, the focal plane pedestal 32 provides a relatively stress-free support structure on which the detector 26 is mounted. It should be recognized, however, that the structure of the focal plane pedestal is provided by way of example only and does not limit the scope of the invention.

The focal plane pedestal 32 includes an end cap member 34 and a low distortion mounting plate 36 commonly referred to as a “base plate”. The end cap 34 is disk-shaped and has a relatively small heat capacity,
Has relatively high thermal conductivity. End cap 34 has first and second surfaces 38 and 40, respectively. First surface 38 is substantially planar. In the illustrated embodiment, the second
The surface 40 of the cryostat assembly is configured to hermetically and hermetically seal the cold finger tube 42.
Defines an internal "expansion" chamber. Cold finger tube 42 has lower Dewar housing assembly 44
Inside and arranged axially. Preferably, the cold finger tube 42 is a relatively thin septum straight cylindrical member having a cold end 46 and a warm end 48 (in view of the respective temperature in use). The cold end 46 is sealed by the second surface 40 of the end cap 34. The interface between the cold end 46 of the cold finger tube 42 and the second surface 40 of the end cap 34 is provided with a thermally stable hermetic seal. Furthermore, since the cold finger tube 42 is a cantilevered support member, it must have sufficient bending rigidity to control the deflection of the focal plane pedestal 32 and thus the detector 26.

The mounting plate 36 has a disk shape having a larger cross-sectional area than the end cap 34. Preferably, the mounting plate
36 is made of a material such as ceramic and forms a relatively stress-free pedestal on which the detector 26 is mounted.
The mounting plate 36 is fixed to the first surface 38 of the end cap 34 using a thermally conductive adhesive.

The rapidly cooled cryostat assembly 10 is axially positioned and secured within the “expansion” chamber of the cold finger tube 42 to absorb thermal energy from the detector 26 to provide optimal detector performance. You. The cold finger tube 42 houses a cooling mechanism (the cryostat assembly 10) for cooling the detector 26 by a heat transfer process from the detector 26 to the low-temperature liquid.
As is known in the art, Joule-Thomson cryostats use high pressure gas that is released to the cold end of the cryostat's expansion chamber. Thereafter, the gas expands and liquefies and absorbs heat from the detector. The liquefied gas is then evaporated or "vaporized" and used to complete the heat transfer cycle. Any high pressure gas (i.e., argon, nitrogen, helium), or combinations thereof, used in a Joule-Thomson cryostat to produce the desired cooling characteristics is considered suitable for use in the present invention. Cold end 46 of cold finger tube 42
The expansion of the gas within the chamber causes thermal energy to
Absorbed from 32, thereby cooling detector 26.

In order to minimize the amount of heat radiation sent to the detector 26 from heat sources other than the scene, a cold shield 50 is typically provided over the detector 26 and disposed centrally. . The cold shield 50 is bonded and fixed to the front surface 52 of the mounting plate 36 by bonding, and is disposed radially outward and coaxial with respect to the detector 26. The cold shield 50 has an opening 54 formed so as not to obstruct the optical path of infrared radiation from the outside that the detector 26 should receive. The cold shield 50 is supported by a fixed off-mounted conical support member 56 between the outer peripheral wall surface of the cold finger tube 42 and the rear surface 58 of the mounting plate 36 and is then thermally conductive. Heat transfer. The cold shield 50 has a thin wall structure and is made of a material with relatively good thermal conductivity. The cold shield 50 preferably has a relatively small heat capacity to reduce the required cooling time. Most modern infrared seeker applications require cooling the detector 26 to about 80 ° K while cooling the cold shield 50 to at least about 200 ° K. More specifically, it is desirable to make cold shield 50 of a material that can be cooled to at least about 150 ° K in about 5 seconds. Cold shield 50
Can be made of 6061-T6 aluminum, but other suitable materials can be used. Rapid cooling of the cold shield 50 is useful for increasing detector sensitivity by reducing electronic noise and improving background scenes.

To enable electrical communication between the detector 26 and external electronics, the wiring associated with the detector 26 is attached to the mounting flange 16.
Through the feed-through port 60. Referring now to FIG. 3, the means for directing an electrical signal from detector 26 to feedthrough port 60 is shown in more detail. In general, the plane on which the infrared detector 26 rests is "metallized" to form a conductive communication path. In particular, a predetermined pattern of a plurality of gold wires 62 is deposited on the front surface 52 of the mounting plate 36 before the detector 26 is mounted. The gold wire 62 extends radially from a position relatively close to the detector 26 to a plurality of positions near the outer periphery of the mounting plate 36. More specifically, the gold wire patterns 62 are spaced along the outer perimeter of the mounting plate 36, beginning at a distance of about 3.17 mm (about 1/8 ") from the two opposing edges of the integrated circuit readout board 30. A plurality of conductive pads 64. One end of the gold wire 62 is connected to the integrated circuit readout board 30 via a wire 66. The wire 66 is attached by wire bonding and is thermally and mechanically operated during cold operation. The conductive pad 64 is also connected to the feedthrough port 60 via the conductive wire 68.
Is wire-bonded to a feedthrough pin 70 extending through the wire. In this way, the electrical signal generated by the detector 26 is sent to an external control electronic circuit (not shown),
As a result, the premature occurrence of fatigue failure of the detector is suppressed to a minimum.

According to the present invention, a rapid cooling cryostat assembly 10
Is the inner cryostat 100 and the outer cryostat 1
02 with a double Joule-Thomson cryostat assembly. The inner cryostat 100 is coaxially arranged inside the outer cryostat 102, and the outer cryostat 102 is further coaxially arranged inside the cold finger tube 42. Inside cryostat
100 comprises a first elongated tubular mandrel 104 made of a rigid structural member made of a material having relatively low heat transfer properties. Use of low thermal conductivity material is the first mandrel
The cooling rate of 104 is slowed, resulting in more cooling of the component to be cooled. Inner cryostat 10
0 further comprises a tubing 106 having a radially extending fin 108 on its surface to form a first finned tube assembly 110. The first finned tube assembly 110 is the first
Is wound spirally around the outer peripheral wall surface 112 of the mandrel 104. The first finned tube assembly 110 is in fluid communication with a remote source of high pressure gas (not shown) and defines a first heat exchange circuit. The first heat exchange circuit is adapted to continuously supply high pressure gas to a plurality of terminal discharge orifices, the purpose and function of which are defined in detail below. The cold end 114 of the first mandrel 104 is sealed with a first cryostat end cap 116. Preferably, the cold end 114 of the first mandrel 104 is adhered to the first cryostat end cap 116 and defines a first long airtight chamber 117. Further, the first cryostat end cap 116 is made of a material having a relatively high thermal conductivity.

The outer cryostat 102 comprises a second elongated cylindrical mandrel 118, the inner cylindrical wall 120 of which is tangential along the radially outermost of the fins 108 of the first finned tube assembly 110. It has a size that makes contact in the direction. Again, for the same reasons as described in the description of the first mandrel 104, the second mandrel 118 is made of a material having low thermal conductivity. The outer cryostat 102 also includes a tubing 122 with radially extending fins 124 on the surface. The tube material 122 is spirally wound around the outer peripheral wall surface of the second mandrel 118 to form a second finned tube assembly 126. Cold finger tube 42
An insulating thread, such as nylon, is tightly wound around the second finned tube assembly 126 to thermally isolate the fins 124 from direct contact. The second finned tube assembly 126 is in fluid communication with a second remote source of high pressure gas (not shown) and defines a second heat exchange circuit. The second finned tube assembly 126 has a plurality of discharge orifices and, as described in more detail below,
The purpose is to maximize the amount of heat absorbed from the detector 26 and the cold shield 50.

At the cold end 128 of the outer cryostat 102, a second cryostat end cap 130 is provided. Preferably, the second cryostat end cap 130 is
Made of a material having a relatively high thermal conductivity to maximize the heat transfer characteristics of the cryostat assembly 10. Typical materials chosen for the second cryostat end cap 130 are copper or tungsten. The second mandrel 118 is sealingly joined to the second cryostat end cap 130 to define a second elongate hermetic chamber 131 within which the inner cryostat 100 is operably disposed. Preferably, a portion of the front surface 132 of the second cryostat end cap 130 is adhesively bonded to the lower surface 40 of the end cap 34 by a thermally conductive adhesive. The use of such a thermally conductive adhesive allows thermal energy to flow efficiently directly from the detector 26 through the focal plane pedestal 32 to the rapid cooling cryostat assembly 10,
The detector 26 and the cold shield 44 are efficiently cooled.
More specifically, the second cryostat end cap
The front face 132 of 130 is stepped to provide a central ridge, the central ridge being adhesively bonded to the end cap 34 of the focal plane pedestal 32. The outer peripheral portion (the portion surrounding the central raised portion) of the front surface 132 of the second cryostat end cap 130 is the second cryostat end cap.
A first annular cavity 134 between 130 and the second surface 40 of the focal plane pedestal end cap 34 is configured to define a cold end 46 of the expansion chamber. Similarly, at the cold end 128 of the outer cryostat 102, a second annular gap 136 is defined between the front surface 138 of the first cryostat end cap 116 and the back surface 139 of the second cryostat end cap 130.

The first finned tube assembly 110 of the inner cryostat 100 terminates in at least one longitudinally oriented discharge orifice 140 and toward the back 139 of the central raised portion of the second cryostat end cap 130. To release the high-pressure gas flowing inside. In this manner, the gas released into the second annular gap 136 expands toward the second cryostat end cap 130 that is in direct contact with the focal plane pedestal 32. Accordingly, the inner cryostat 100 provides direct cooling of the focal plane pedestal 32. In addition, the first finned tube assembly 110 of the inner cryostat 100 extends along the outer peripheral wall of the first mandrel 104 and the cold end 128 of the outer cryostat 102.
A plurality of radially oriented discharge orifices 142 disposed in close proximity to the orifices. In this manner, the radially oriented discharge orifice 142 is directed toward the second cryostat end cap 130 to “pre-cool” the cold end 128 of the outer cryostat 102. The discharge orifice 142 seeks to obtain a relatively high film coefficient by the outflow velocity of the gas discharged from the orifice.

The second finned tube assembly 126 of the outer cryostat 102 terminates in a plurality of longitudinally directed discharge orifices 144 that generally surround the central raised portion of the second cryostat end cap 130. A discharge orifice 144 is provided within the first annular gap 134 to directly cool the focal plane pedestal 32. In addition, a second finned tube assembly 126 surrounds the outer periphery of the second mandrel 118 and is disposed adjacent the cold end 46 of the cold finger tube 42 with a plurality of radially directed discharge orifices 14.
6 is provided. More specifically, the radially oriented discharge orifice 146 is a remotely mounted conical support member 5.
6 and is adapted to directly cool its conical support member 56 to conduct cooling of the cold shield 50. The high outflow velocity of the high pressure gas ejected from the discharge orifice 146 provides a high film coefficient and maximizes heat transfer from the cold shield 50 via the conical support member 56.
In this way, rapid cooling of the cold shield 50 is achieved by directing the orifices 146 radially directed toward the conical support member 56.

Obviously, to cool the detector 26, the first and second
Both heat exchange circuits emit high-pressure gas toward the focal plane pedestal 32. The spacer cap member 150 and the ring 152 cooperate with the warm end 42 of the rapid cooling cryostat assembly 10 to form the inner cryostat 100 and the outer cryostat 1.
02 and relative positions of the annular gaps 134 and 136 are defined and maintained. As shown, an absorbent material, such as felt 160, fills the annular voids 134 and 136. The felt 160 retains liquid cryogenic fluid (cryogen) generated near the respective cryostat end caps 116 and 130 and the pedestal end cap 34 as a result of gas expansion, and the liquid cryogenic fluid evaporates within the felt 160. To provide a relatively stable cooling environment.
The use of felt 160 narrows the range of temperature fluctuations and therefore
The temperature change rate of the detector 26 is reduced. In addition, felt 16
The use of zero results in a reduction in vapor pressure in the area to be cooled by retaining the liquid cryogenic fluid in proximity to the detector 26 and focal plane pedestal 32 that require the most cooling capacity. In this way, the high-pressure gas is guided to a place requiring a strong low-temperature cooling capacity and expanded. In this way, rapid cryogenic cooling over a relatively large area is achieved by the high pressure gas released at the structural location to be cooled most efficiently in the expansion chamber. After passing through the area providing useful cooling, the cryogenic fluid retreats through the fins 108 and 124 of the inner and outer cryostats, respectively, in countercurrent heat exchange with the incoming high pressure gas inside the tubing 106 and 122.

The present invention provides a dual joule load for cooling a high joule load detector and dewar assembly to a desired temperature with substantially less cooling time than conventional cryostat assemblies.
A Thomson rapid cooling cryostat assembly 10 is used. Thus, more efficient cold cooling of the focal plane pedestal 32 and the detector 26 occurs. In addition, the outer cryostat 10
The cold shield 50 cools much more rapidly than previously known because the high outflow velocity of the gas emanating from the second terminal orifice results in a relatively high film coefficient to directly cool the support member 56.

In another embodiment, the second cryostat end cap 130 of the outer cryostat 102 is modified
It is conceivable to provide an opening extending through the second surface 42 of the end cap 34. In this case, the second annular gap
The low temperature cooling provided by the inner cryostat 100 in 136 is directly transferred to the focal plane pedestal 32.

With the understanding of the detailed description, drawings and claims of the present invention, it is possible to obtain other advantages by using the present invention, and to make modifications without departing from the true spirit of the present invention. Something is obvious to those skilled in the art. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a longitudinal sectional view of an infrared seeker assembly with an enhanced performance rapid cooling cryostat showing the relevance of the operation of various components.

FIG. 2 is an enlarged view of a cold end of the performance improving cryostat assembly of FIG. 1;

FIG. 3 is a plan view of FIG. 1 with the dewar housing and cold shield removed to show the electrical connection of the components.

[Explanation of symbols]

 10 Rapid cooling cryostat assembly 12 Detector assembly 14 Hole 16 Mounting flange 18 Deer housing 20 Central opening 22 Infrared window material 24 Getter 25 … Internal cavity 26 Detector device 30 Integrated circuit readout board 32 Focal plane pedestal 34 End cap 36 Mounting plate 42 Cold finger tube 50 Cold shield 54 … Opening 56 …… Off-mount conical support member

Continuation of the front page (56) References JP-A-5-180691 (JP, A) JP-A-2-236125 (JP, A) JP-A-2-148427 (JP, U) JP-A-2-107041 (JP) U.S. Pat. No. 2,107,040 (JP, U) U.S. Pat. No. 4,954,708 (US, A) U.S. Pat. No. 4,918,312 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01J 5/02 G01J 5/48 G01V 9/04

Claims (15)

(57) [Claims] The cold end of a cold finger tube for providing a vacuum dewar for simultaneously cooling a detector and a cold shield supported on a focal plane pedestal, said focal plane defining an expansion chamber within the detector assembly. A cryostat device for use in the detector assembly of the type that is in thermal communication with a portion, comprising: a first tubular mandrel and a first end cap formed to enclose the first mandrel. An outer cryostat arranged in the axial direction of the cold finger tube, and wound around an outer peripheral wall of the first mandrel,
A first supply pipe for supplying a pressurized cryogenic fluid for cooling a first region located adjacent to the focal plane pedestal and proximate to the cold end of the cold finger tube; First orifice means cooperating with the first supply pipe to discharge the pressurized cryogen in one area to cool the focal plane pedestal and detector; and A second orifice means cooperating with the first supply pipe to release fluid and cool the cold shield; a second orifice formed to enclose the second cylindrical mandrel and the second mandrel. Two end caps, the second end caps being displaced from the first end caps and defining a second cooled region, axially arranged within the first mandrel. Inside cryos And Tsu DOO, be wound around the outer peripheral wall of said second mandrel,
A second supply pipe for supplying a pressurized low-temperature fluid to the second cooled area; releasing the pressurized low-temperature fluid in the second area to release the focal plane pedestal and the detection; Third orifice means cooperating with the second supply pipe to cool the vessel, and cooperating with the second supply pipe to discharge the pressurized cryogen and cool the outer cryostat. And a fourth orifice means. 2. The apparatus of claim 2, further comprising a support member fixed between the cold end of the cold finger tube and the cold shield, wherein the support member is made of a material having a relatively high thermal conductivity and is close to the cold shield. The cryostat device according to claim 1, wherein the cryostat device is disposed so as to form a relatively good heat conduction path between the cryostat device and the cold shield. 3. The first and second mandrels are made of a relatively low thermal conductivity material, and the first and second end caps are made of a relatively high thermal conductivity material. The cryostat device according to 1. 4. The cryostat device according to claim 2, wherein the first supply pipe has a first fin on a surface thereof, and the cold fluid flowing from the cold finger cold end and the first area is supplied to the first supply pipe. Cooling the pressurized cryogenic fluid that passes over the first fin and flows through the first supply tube toward the first and second orifice means; Has a second fin on a surface thereof, and a cryogen flowing from the first end cap in the second area passes over the second fin and passes through the second supply pipe. A cryostat device for cooling the pressurized cryogenic fluid flowing toward third and fourth orifice means. 5. The first and second cooled regions form first and second annular gaps, respectively, and the first and second annular gaps contain an absorbent material filled therein. 5. The method of claim 4, wherein the absorbent material has a relatively low heat capacity to facilitate relatively constant cooling during expansion of the pressurized cryogenic fluid in the first and second annular voids.
The cryostat device as described. 6. The first orifice means includes a first discharge orifice extending through the first supply tube, the first discharge orifice directly cooling the focal plane pedestal and providing the detector with the first orifice. The cryostat device of claim 5, wherein the cryostat device is directed to discharge a cryogenic fluid pressurized to absorb heat from the first annular cavity. 7. A second discharge means extending through said first supply tube disposed along a periphery of said first mandrel for directly cooling said support member. 7. The cryostat device according to claim 6, further comprising an orifice to reduce a cooling time required to cool the cold shield to a desired cryogenic temperature. 8. The third orifice means includes a third discharge orifice extending through the second supply pipe, the third discharge orifice cooling the first end cap. The third orifice is configured to direct pressurized cryogenic fluid into the second annular cavity, wherein a portion of the first end cap is configured to contact a focal plane pedestal. The cryostat device according to claim 7, wherein the surface pedestal is directly cooled to absorb heat from the detector. 9. The fourth orifice means extends through the second supply tube located along the periphery of the second mandrel and is directed to pre-cool the outer cryostat. 9. The cryostat according to claim 8, further comprising a discharge orifice. 10. The method according to claim 10, wherein said detector is at least about 80 K and said cold shield is at least about 200 K.
10. Operate to cool at the same time in less than seconds.
The cryostat device as described. 11. A dewar housing defining a vacuum cavity, a focal plane pedestal in the vacuum cavity, a detector mounted on a first surface of the focal plane pedestal, concentrically surrounding the detector, And a cold shield attached to the first surface of the focal plane pedestal; and an end hermetically sealed to a second surface of the focal plane pedestal to define a cold end, wherein the cold end is the focal point. A cold finger tube in thermal communication with the seat, a thermally conductive support member for forming a relatively high heat conduction path between the cold end and the cold shield, the detector and the cold shield And cooling means for simultaneously cooling to a respective low temperature within a predetermined time, wherein the cooling means comprises an inner cryostat concentrically arranged on the cold finger. Cooling means having a side cryostat, wherein the inner cryostat is provided with first supply means for feeding a pressurized cryogen to the cold end of the cold finger tube; and First orifice means oriented to discharge a fluid, and pre-cooling the outer cryostat while cooling the focal plane pedestal and the detector, wherein the outer cryostat is mounted on the cold finger tube. A second supply means for delivering a pressurized cryogen to a cold end; and a second orifice means oriented to discharge the pressurized cryogen, the focal plane A detector assembly for cooling the cold shield simultaneously with cooling the pedestal and the detector. 12. The heat conductive support member is fixed between an outer surface of the cold finger tube and the second surface of the focal plane pedestal, and the support member is disposed proximate to the cold shield. 12. The detector assembly according to claim 11, wherein 13. A method for simultaneously cooling an electromagnetic wave detector and a cold shield both mounted on a focal plane pedestal thermally conductively coupled to a cold finger tube in a vacuum dewar of the detector assembly, An inner cryostat in communication with a first source of pressurized cryogen and an outer cryostat in communication with a second source of pressurized cryogen, wherein the inner and outer cryostats are within the cold finger. Inserting a double Joule-Thomson cryostat assembly concentrically disposed within said cold finger tube; and providing a support member to said cold finger tube to provide relatively high thermal conductivity communication between each other. Closely arranged between the cold finger tube and the focal plane pedestal And securing the serial support member, the second in order to cool the detector supported within
Discharging a pressurized cryogen from the source to the focal plane pedestal; and pressing the pressurized cryogen from the second source to cool the cold shield to the support member. Discharging a pressurized cryogenic fluid from the first source toward the focal plane pedestal to cool the detector support; and preparatory to the outer cryostat. Discharging a pressurized cryogenic fluid from the first source toward the focal plane pedestal for cooling. 14. The inner cryostat includes a first cylindrical mandrel and a first end cap member that closes a terminal of the first mandrel disposed near a cold end of the cold finger tube. Wherein the cold end is in thermal communication with the focal plane pedestal, the first mandrel is made of a material having a relatively low thermal conductivity, and the first end cap has a relatively high thermal conductivity. 14. The method of cooling a detector assembly according to claim 13, wherein the detector assembly is made of the following materials. 15. The outer cryostat includes a second cylindrical mandrel and a second end cap member that closes a terminal of the second mandrel disposed near a cold end of the cold finger tube. Wherein the cold end is in thermal communication with the focal plane pedestal, the second mandrel is made of a material having a relatively low thermal conductivity, and the first end cap has a relatively high thermal conductivity. Made of material,
15. The method of cooling a detector assembly according to claim 14, wherein said second end cap is formed to have a portion that contacts said focal plane pedestal.