COMBINED STRUCTURE OF UHV CHARACTERIZATION INSTRUMENT-INTERCONNECTED IN-SITU REACTION CELL AND BUILT-IN MASS SPECTROMETER ELECTRIC QUADRUPOLE

Abstract

A coupling structure of a UHV characterization instrument-interconnected in-situ reaction cell and a built-in mass spectrometer electro quadrupole is provided. One end of a stainless steel capillary is connected to a segregated in-situ reaction cell gas output pipeline, and the other end of the stainless steel capillary is a sampling port. A sampling gas flowing out of the sampling port is divided into two gas paths, wherein, one gas path enters a vacuum buffer chamber through a valve with a low flow control ratio, and the other gas path enters a mass spectrometer electro quadrupole through a valve with a high flow control ratio. When the mass spectrometer electro quadrupole performs sampling gas composition analysis on the interconnected in-situ reaction cell, its sampling time delay is negligible and the sampling analysis requirements for in-situ analysis of continuity, real-time and high time resolution are met.

Claims

1. A coupling structure of a UHV characterization instrument-interconnected in-situ reaction cell and a built-in mass spectrometer electro quadrupole, comprising a segregated in-situ reaction cell, wherein, an in-situ reaction cell gas output pipeline is connected to the independent segregated in-situ reaction cell, and the segregated in-situ reaction cell connects with a vacuum buffer chamber; a sample is transferred to a sample chamber of a UHV characterization instrument through a vacuum interconnecting transfer device, and the vacuum buffer chamber is separated from the sample chamber by a 1.sup.st gate valve; the sample chamber connects with a mass spectrometer electro quadrupole, and a turbo molecular pump-mechanical pump set is configured on the sample chamber; wherein, a first end of a stainless steel capillary pipeline is connected to the in-situ reaction cell gas output pipeline, and a second end of the stainless steel capillary pipeline is a sampling port; a sampling gas flowing out of the sampling port is divided into two gas paths, wherein, a first gas path of the sampling gas enters the vacuum buffer chamber through a first valve with a low flow control ratio, and a second gas path of the sampling gas enters the mass spectrometer electro quadrupole through a second valve with a high flow control ratio.

2. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 1, wherein, a flange is connected between the vacuum buffer chamber and the segregated in-situ reaction cell, and the flange is provided with a viewport for monitoring sample transfer; and wherein when the vacuum buffer chamber comprises an idle flange port, the idle flange port is changed to a ferrule tube to flange adapter; and when the vacuum buffer chamber does not comprises the idle flange port, the above flange is by employing a 2.sup.nd tee flange, the flange with the viewport for monitoring sample transfer is provided in a straight-through direction of the 2.sup.nd tee flange, the flange port in a non-straight-through direction of the 2.sup.nd tee flange is the idle flange port, and the idle flange port is changed to the ferrule tube to flange adapter; and wherein the first gas path of the sampling gas enters the vacuum buffer chamber via the ferrule tube to flange adapter through the first valve with the low flow control ratio.

3. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 1, wherein, the first valve with the low flow control ratio comprises a bonnet needle valve.

4. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 1, wherein, the second valve with the high flow control ratio comprises a high precision metering needle valve.

5. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 2, wherein, the sampling port of the stainless steel capillary pipeline is connected to a protection ball valve.

6. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 5, further comprising a 1.sup.st tee flange, three flange ports of the 1.sup.st tee flange are connected to the sample chamber, the mass spectrometer electro quadrupole and the second valve with the high flow control ratio, respectively.

7. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 6, wherein, one of the three flange ports of the 1.sup.st tee flange is connected to the second valve with the high flow control ratio, and the 1.sup.st tee flange is separated from the second valve with the high flow control ratio by a 2.sup.nd gate valve.

8. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 7, wherein, the ferrule tube to flange adapter, the stainless steel capillary pipeline, the protection ball valve, the first valve with the low flow control ratio, the second valve with the high flow control ratio, and the second gate valve connect with each other to form an installation module.

9. The coupling structure of the UHV characterization instrument-interconnected in-situ reaction cell and the built-in mass spectrometer electro quadrupole according to claim 1, wherein, the stainless steel capillary pipeline performs a sampling on the in-situ reaction cell gas output pipeline, and is then directly adapted to a stainless steel pipeline with an amplified outer diameter, wherein the amplified outer diameter of the stainless steel pipeline is equal to or larger than of inch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG. 1 is a schematic diagram of a layout structure in the prior art of an ultra-high vacuum characterization instrument interconnected with an in-situ reaction cell;

[0051] FIG. 2 is a layout diagram of a coupling structure of a UHV characterization instrument-interconnected in-situ reaction cell and a built-in mass spectrometer electro quadrupole according to the present invention; and

[0052] FIG. 3 is an example of a sampling signal of the mass spectrometer electro quadrupole.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] In order to make the present invention more obvious and understandable, the preferred embodiments are described in detail with reference to the drawings as follows.

[0054] As shown in FIG. 2, the present invention provides a coupling structure of a UHV characterization instrument-interconnected in-situ reaction cell and a built-in mass spectrometer electro quadrupole. According to the prior patent solution, it is necessary to complete performing sampling from the in-situ reaction cell gas output pipeline 9 by the mass spectrometer electro quadrupole 7. In order to use the original configuration hardware of the ultra-high vacuum characterization instrument to achieve this assembly scheme, first of all, it is necessary to change the original two vacuum flanges of the ultra-high vacuum characterization instrument to flange adapters, which are two vacuum interfaces required for real-time sampling in the prior patent solution. Modification of first flange: the nipple flange 10 that connects the mass spectrometer electro quadrupole 7 and the ultra-high vacuum characterization instrument is changed to the first tee flange 12. Modification of second flange: one idle flange port on the vacuum buffer chamber 2 is changed to the ferrule tube to flange adapter 13 (the one idle flange port on the vacuum buffer chamber 2 may also be adapted to a ferrule tube having a larger diameter than that of this preferred embodiments). The remaining pipeline connections can all be completed outside the ultra-high vacuum characterization instrument. The stainless steel capillary 14 is connected to the in-situ reaction cell gas output pipeline 9 to form a sampling port, and the sampling port is protected by the 1/16 ball valve 15. A sampling gasline is divided into two gas paths, wherein, one gas path enters the vacuum buffer chamber 2 by connecting with the ferrule tube to flange adapter 13 through the bonnet needle valve 16 (low flow control ratio) as a differential gas path in the prior patent solution; and the other gas path enters the mass spectrometer electro quadrupole 7 by connecting with the first tee flange 12 through the high precision metering needle valve 17 (high flow control ratio) for analysis and sampling.

[0055] When the mass spectrometer electro quadrupole 7 does not need to sample the independent in-situ reaction cell 1, the second gate valve 18 is turned off, and the sample chamber 5 and a main chamber of the ultra-high vacuum characterization instrument connected with the sample chamber 5 are completely unaffected by the expanded and extended sampling part. Meanwhile, the 1/16 ball valve 15 is turned off, and the vacuum of the expanded and extended sampling part newly added is preserved by the vacuum buffer chamber 2. Moreover, the vacuum level of the vacuum buffer chamber 2 itself will not be affected.

[0056] In the solution of FIG. 2, by means of the pipeline design of the present invention, the existing main hardware devices, i.e. the mass spectrometer electro quadrupole 7, the first turbo molecular pump-mechanical pump set 3 and the second turbo molecular pump-mechanical pump set 8 form a topological structure relationship completely consistent with the prior patent solution, so that the online analysis of the gas composition during the preparation process in the independent in-situ reaction cell 1 is realized by means of the in-situ reaction cell gas output pipeline 9 through these hardware devices. Specifically, the first turbo molecular pump-mechanical pump set 3 actually plays the role of the differential pump set in the prior patent solution. When the pressure of the independent in-situ reaction cell 1 is relatively high, the split flow of the sampled gas flow to the first turbo molecular pump-mechanical pump set 3 can be increased by adjusting the bonnet needle valve 16, and the high precision metering needle valve 17 is cooperatively adjusted, so that even if the independent in-situ reaction cell 1 is at the maximum pressure of 10 bar, the pressure next to the mass spectrometer electro quadrupole 7 will be stably controlled at 10.sup.6 mbar or less. This ensures that any ultra-high vacuum characterization instrument is quickly restored to the background pressure of 10.sup.10 mbar after this characterization operation is completed.

[0057] If the vacuum buffer chamber 2 does not have the idle flange, the flange 11 with a viewport for monitoring sample transfer may be changed to the second tee flange of the same diameter, the flange with the viewport for monitoring sample transfer is retained in the straight-through direction, and one idle flange port is purposingly added in the non-straight-through direction of the second tee flange which is newly added to complete the modification of the above second flange port. In order to cooperate with the vacuum interconnecting transfer device 4 to transfer a sample in the vacuum buffer chamber 2, a plurality of observation windows must be equipped, and thus the position of the ferrule tube to flange adapter 13 is guaranteed.

[0058] The above ferrule tube to flange adapter 13 is required to be adapted to a stainless steel pipeline with an outer diameter of inch or larger.

[0059] The following is an example of upgrading and modifying an XPS analysis device equipped with a vacuum interconnected in-situ reaction cell to further illustrate the present invention.

[0060] The XPS analysis device is purchased from ThermoFisher of model ESCA 250Xi; both the vacuum interconnection device and the independent in-situ reaction cell 1 are purchased from Fermi Instruments, wherein the model of the independent in-situ reaction cell 1 is HPGC 300; the model of the mass spectrometer electro quadrupole 7 is SRS300; and both the models of two turbo molecular pump-mechanical pump sets are Edward. Specifically, because the molecular pump is configured according to the ultra-high vacuum characterization instrument, the pumping speed of the molecular pumps are greater than 200 L, which is much higher than the pumping speed required by the prior patent solution. This is the normal situation of the configuration of the ultra-high vacuum characterization instrument, and thus the sampling control result obtained by the present invention patent in a practical application is better than the embodiment of the prior patent solution. In the implementation of mass spectrometry signal acquisition, the pressure of the sample chamber 5 is always stabilized at a set value of 10.sup.6 mbar or less, while a stable and clear signal for the gas composition with a content of 1 ppm still exists under the condition of 10.sup.8 mbar. FIG. 3 shows a sampling signal of a very short helium pulse next to the in-situ reaction cell gas output pipeline 9 obtained by the mass spectrometer electro quadrupole 7, and there is no obvious time delay (which is far less than the sampling interval of the mass spectrometer electro quadrupole) between its corresponding time and the occurrence time of the helium pulse. In an actual operation, by adjusting the flow ratio of the sampling signal through the bonnet needle valve 16 and the high precision metering needle valve 17, the mass spectrometer electro quadrupole 7 has a sensitive signal response to the independent in-situ reaction cell 1 under a vacuum condition of 0.01 bar to a medium-high pressure condition of 10 bar, which exceeds the design requirement of the pressure of 1 to 10 bar in the sampling area. After the mass spectrometer electro quadrupole 7 completes performing sampling from the independent in-situ reaction cell 1, the 1/16 ball valve 15 and the second gate valve 18 are separately turned off, and the vacuum buffer chamber 2 and the sample chamber 5 are restored to an optimal vacuum background within a few minutes.

[0061] In the present embodiment, the connection between all the hardware devices and the ultra-high vacuum characterization instrument conforms to the structure of FIG. 1.

[0062] In the connection of the expanded and extended sampling pipelines of the mass spectrometer electro quadrupole 7, the 1/16 ball valve 15, the bonnet needle valve 16, the high precision metering needle valve 17 and the pipeline fittings connected to them all employ domestic valves, which are mainly purchased from Shanghai X-tec Fluid Technology Co., Ltd. The added gate valve is purchased from the VAT brand.

[0063] Preferably, in installation, the distance between the capillary and the X-ray characterization instrument is minimized, reducing the gas delay time in the pipeline, and this delayed time relative to the dead volume of the in-situ reaction cell is negligible.

[0064] Preferably, the stainless steel capillary 14 performs a sampling on the in-situ reaction cell gas output pipeline 9 and is then directly adapted to a stainless steel pipeline with an amplified outer diameter of inch or larger, so as to achieve the maximum vacuum flow conductance. That is, the connection with the mass spectrometer instrument achieves zero time delay.

[0065] Preferably, in FIG. 2, acting as the pipeline fittings of the mass spectrometer electro quadrupole 7 to perform direct sampling on the independent in-situ reaction cell 1, the mass spectrometer electro quadrupole 7, the ferrule tube to flange adapter 13, the special stainless steel capillary pipeline 14, the 1/16 ball valve 15, the bonnet needle valve 16, the high precision metering needle valve 17 and the second gate valve 18 all connect with each other to form an installation module, facilitating the disassembly and experimental operations. The entire installation process does not affect the overall operation of the ultra-high vacuum characterization instrument and does not cause vacuum breakdown to the main instrumentation chamber.

[0066] Preferably, by means of the modular installation design, the newly added sampling expanded and extended functional module of the mass spectrometer electro quadrupole 7 connects with the chambers of the original ultra-high vacuum characterization instrument only through the first tee flange 12 and the ferrule tube to flange adapter 13. When the mass spectrometer electro quadrupole 7 does not perform the expanded and extended sampling function for the independent in-situ reaction cell 1, the 1/16 ball valve 15 and the second gate valve 18 are simply separately turned off, so that the vacuum buffer chamber 2 and the sample chamber 5 are restored to the work structure before modification, and the newly added sampling expanded and extended functional module is also under the protection of ultra-high vacuum.

[0067] Preferably, on the basis of the prior patent solution, the bonnet needle valve 16 and the high precision metering needle valve 17 are used to regulate the split flow of the sampled gas flow. In combination with the advantage of the large pumping speed and the good vacuum background owned by the molecular pump of the ultra-high vacuum characterization instrument, it is realized that when the mass spectrometer electro quadrupole 7 performs direct sampling from the independent in-situ reaction cell 1 (1 to 10 bar), the pressure of the sample chamber 5 is always stabilized at the set value of 10.sup.6 mbar or less, and up to 10.sup.8 mbar there is still a stable and clear signal for the gas component with a concentration of 1 ppm.

[0068] Preferably, by means of the pipeline design of the present invention, a direct vacuum transition from the independent in-situ reaction cell 1 (1 to 10 bar) to the mass spectrometer electro quadrupole 7 (10.sup.8-10.sup.6 mbar) is realized. After the mass spectrometer electro quadrupole 7 completes direct sampling from the independent in-situ reaction cell 1, the vacuum buffer chamber 2 and the sample chamber 5 are restored to the optimal vacuum background within a few minutes.

[0069] Preferably, by means of the pipeline design, the important hardware devices of the original ultra-high vacuum characterization instrument is fully utilized, including the mass spectrometer electro quadrupole 7, the second turbo molecular pump-mechanical pump set 8 and the first turbo molecular pump-mechanical pump set 3, which account for 90% or more of the hardware cost of the prior patent solution, greatly saving the device costs.

[0070] In summary, based on the characteristics of the devices, the present invention provides an online mass spectrometry sampling and analysis function for the in-situ reaction cell of the ultra-high vacuum characterization instrument at an extremely low cost, expands the analysis capability of the built-in mass spectrometer electro quadrupole of the ultra-high vacuum characterization instrument to a gas reaction environment of 1 to 10 bar, and completely covers the accuracy requirements corresponding to pressure and gas composition range of the in-situ reaction cell of the ultra-high vacuum characterization instrument. The sampling part meets: (i) the requirement of real-time sampling, no time delay, and sensitive response to the acquisition of trace pulses; (ii) the pressure range of the in-situ reaction cell of the ultra-high vacuum characterization instrument, that is, the upper limit requirement of the medium-high pressure, and (iii) the original operation requirements of the ultra-high vacuum characterization instrument without changing its basic structure when the extension and expansion function is implemented. Moreover, the sampling part is easy to install, small in volume, clear in module design, and does not affect the use of other functions of the original instrument and personnel action, which is also helpful for monitoring other similar related environments or fundamental research on chemical engineering reaction.