Roughing Pump Research Articles

In-Line Thermal Desorption and Dielectric Barrier Discharge Ionization for Rapid Mass Spectrometry Detection of Explosives.

Thermal desorption (TD) of wipe-based samples was coupled with an in-line dielectric barrier discharge ionization (DBDI) source and rugged compact time-of-flight mass spectrometer (MS) for the detection of explosives, propellants, and postblast debris. The chromatography-free TD-DBDI-MS platform enabled rapid and sensitive detection of organic nitramine, nitrate ester, and nitroaromatic explosives as well as black powder and black powder substitute propellants. Parametric investigations characterized the response to TD temperature and optimized DBDI voltage, aerodynamically assisted entrainment, and fragmentation through in-source collision induced dissociation (isCID). Excess nitrate generated by the DBDI source yielded predominantly nitrate-adduct formation. Subnanogram sensitivities were demonstrated for all explosives investigated, except for nitroglycerin, specifically due to its volatility. Further, most analytes/explosives exhibited tens of picograms sensitivities. The platform also demonstrated the detection of propellant and military explosives from postblast debris. The TD-DBDI-MS system performed well without the need for aerodynamically assisted entrainment (and the associated rough pump), which along with requiring no additional gases (i.e., N2 or He) or solvents, aid in potential field deployment. The ease of TD-DBDI attachment and removal added trace solid or liquid residue detection to the rugged mass spectrometer, designed primarily for the analysis of volatile organic and inorganic compounds.

Vacuum Pumping System for ITER's Deuterium Tritium Operational Campaign

SummaryIn the ITER fusion experiment the torus vacuum pumping system is mainly involved in pumping plasma exhaust gases consisting of Deuterium/Tritium (DT) and trace quantity of helium. The currently proposed plasma operation plan for the six torus cryopumps is staggered for all fueling rate and plasma durations and therefore variable tritium inventories need to be handled. The ITER cryopumps and the backing vacuum pumping system are custom made tritium compatible pumping trains. Their compliant matrix not only asks for pumping efficiencies and hydrogen confinement but also respecting the specific tritium and deuterium (DT) inventories for measures on radiation protection and fire safety. In this article, we present a possible operation plan for torus vacuum pumping system in combinations with roughing pump trains for the ITER baseline plasma scenario. The operation of the vacuum system is driven by DT inventories in the different pumps and building sectors.The primary vacuum pump is torus cryogenic pump (TCP) followed backing roughing pump trains comprise the cryogenic viscous flow compressor (CVC), tritium compatible scroll and Roots pumps. The TCPs are regenerated during timed intervals for an uninterrupted and safe torus operation. Next to the demanding long pulse operation (1 hour) we present an operation plan for inductive short pulse (450 s), hybrid pulse (1000 s) and dwell time vacuum pumping operations [1]. However, the inductive and hybrid pulses are not as critical as long pulse operation pertaining to tritium and hydrogen inventory management.

Experimental Investigation of Tritium Compatible Stainless Steel Roots Pumps

SummaryThe tritium compatible Roots pump Okta 1500 (Pfeiffer Vacuum) is designed for pumping light gas species consisting of diluted radioactive gas, especially tritium mixed with other hydrogen isotopes and helium. Therefore, the pump is constructed of stainless steel and equipped with a special gas lubricated mechanical seal.The series of experiments presented in this work include the evaluation of the performance and an integrity check of the glide ring seal as well as the determination of the light gas pumping performance at low pressure. Those qualifications are needed for efficient embedding of the pump in the International Thermonuclear Experimental Fusion Reactor (ITER) project. As a nuclear facility (Installation Nucléaire de Base, INB) ITER is operated in accordance with the French nuclear safety regulations (INB guidelines) that demand qualification and integrity of the tritium bearing equipment to maintain performance and confinement of active gases at every stages via design, testing, commissioning, operation and surveillance. The experimental methodologies and findings are important to advocate the qualification of the pump for the purpose of radioactive light gas pumping as a roughing pump to back Torus high vacuum cryogenic pump.

A novel method for removing noncondensable gas from loop heat pipe

Noncondensable gas (NCG) is a critical issue in loop heat pipes (LHPs) for space missions and can arise due to plenty of reasons. Compensation chamber (CC) of an LHP, being a nearly stagnant point, accumulates NCG that arises due to any reason. NCG in an LHP intended for space use should be removed before its hermetic sealing itself. In this paper, a novel method is presented for the first time to completely remove NCG from LHPs through a series of attempts using a simple setup consisting of a pressure sensor, a rough vacuum pump and a metering valve connected to the CC. The method is demonstrated on an LHP with flat evaporator with acetone as working fluid and air as NCG. When the LHP operates, a certain amount of NCG is removed from the CC through the vacuum pump by momentarily opening and closing the metering valve in each attempt. Through a series of test runs, based on a decrease in the operating temperature and an increase in the maximum heat transport prior to deprime in each test run with reference to those of the previous test run, it is ascertained that a certain amount of NCG is removed in each attempt. A unique model is also proposed to predict the NCG mass based on the CC pressure and the predicted CC liquid level. Results of the proposed model are validated with those of previous experiments in the LHP containing capacitance gauge for CC liquid level measurement.

Analytical ‘steady-state’-based derivation and clarification of the courant-friedrichs-lewy condition for pipe flow

This article addresses the problem of choosing the optimal discretization grid for emulating fluid flow through a pipeline. The aggregated basic flow model is linearized near the operating point obtained from the steady state analytic solution of the differential equations under consideration. Based on this model, the relationship between the Courant number (μ) and the stability margin is examined. The numerically set coefficient μopt, ensuring the maximum margin of stability, is analyzed in terms of the physical and technological parameters of the flow. As a result of this analysis, a specific formula is obtained based on parameters describing the mechanics (geometry and physics) of the flow through the pipeline, which leads to the optimal value of the Courant number, separately for smooth and rough pumping conditions. A more detailed analysis of the distribution of the optimal μ coefficient in relation to the parameters of the pipeline flow mechanics shows four cases to consider when determining the coefficient μopt. Surprisingly, in three cases, the CFL condition is insufficient, which is expressed in the form of the proposed procedure for choosing the optimal value of μ. The final dichotomous model is derived from the Monte Carlo simulation results in which the effect of each parameter on the optimal Courant number is estimated and consolidated. Taking into account the recognized general laws of physics and using numerical methods and mathematical analysis, simple and useful analytical relationships describing the flow process are obtained. In addition, computer simulations are performed to verify the correctness of the proposed procedure, as well as a number of other considerations related to the modeling of fluid flow in transport pipelines.

Tandem-in-time mass spectrometry analysis facilitated by real-time pressure adjustments

The pressure conditions are important for performing a variety of ion manipulations in mass spectrometers including ion transfer, ion dissociation and mass analysis. In contrast with lab-scale instruments, miniature mass spectrometers typically have simple configurations and reduced pumping power. In this study, a new design of configuration was implemented for a miniature ion trap mass spectrometer with a discontinuous atmospheric interface, realizing a real-time pressure adjustment within a single scan cycle to obtain optimal performance for different stages in a tandem-in-time mass analysis. Gas introduction from the connection between the turbo and rough pumps was used to elevate the vacuum pressure, with pinch valves and needle valves used to set the levels desirable. Pressures in a wide range from 0.01 mtorr to 10 mtorr could be set with great adjustability and stability. Multiple MS/MS analyses could be performed using a single ion introduction, with mass-selective ion transfer and collision induced dissociation at 2 mTorr while mass analysis below 0.5 mTorr.

Research on detection method of leakage rate of rough pumping valve in space environment simulator

As an important part of the vacuum system in the space environment simulator, the rough pumping system reduces the vacuum degree of the container from atmospheric pressure to the pressure of the high vacuum system when the space environment simulator starts up. As the key equipment of the rough pumping system, the rough pumping valve plays the role of isolating the rough pumping system from the environmental simulator, and its leakage rate has a direct impact on the vacuum degree that the space environment simulator can reach. Therefore, it is very important to detect the leakage rate of the rough pumping valve. In this paper, the leakage rate detection method of the rough pumping valve is introduced, including the valve delivery stage and valve installation stage to the simulator stage, in order to provide some basis for the follow-up valve leakage rate detection work

The tritium extraction and removal system for the DCLL-DEMO fusion reactor

During the pre-conceptual design phase of DEMO, different alternatives have been explored to be implemented as tritium extraction and removal system (TERS) for the blanket concepts considered in EUROfusion. The TERS is conceived to extract tritium from the breeder and to route it to the Tritium Plant for final processing. A careful review showed that those blankets operated with PbLi should use the permeation against vacuum (PAV) technique as primary option which is based on a one-step, fully continuous procedure. In this paper, a conceptual design of the TERS for the dual coolant lithium lead (DCLL) breeding blanket is presented, based on the European DEMO2015 layout (18 sectors, 2037 MW fusion power). The P&ID of the proposed TERS, integrated in the DCLL-PbLi loop, includes valves and instrumentation, as well as a revised design of the DCLL-PAV. The dimensioning of the permeator considered a tritium extraction efficiency of 80%. An exhaustive investigation on the vacuum system needed for the PAV is also presented. The choice of the most promising vacuum systems took into account the reliability and tritium compatibility of both high and rough pumps. Their pumping requirements, which are dependent on the PAV efficiency, tritium solubility and tritium partial pressure in the loop, are also discussed in this work.

Development of a low-debris laser driven tape drive soft x-ray source

This paper focuses on debris mitigation in a laser driven tape drive x-ray source. A smart design is being used to minimise the effect of shockwave reflection from the target's back and a continuous rough pumping is utilised to obtain an efficient purging of big lumpy debris particles out of the interaction chamber. The effect of low pressure (3–6 mbar) nitrogen buffer gas is studied together with a moderate magnetic field (0.14 Tesla) on both debris spall and hot ions trajectory. The target material for this work is a 15 μm VHS video tape composed of Mylar as carrier film with Fe2O3 and CrO2 powder. The experiments were conducted using a long pulsed 800ps, 50 Hz Nd: YAG laser. The results obtained appeared to be promising in reducing the damaging effect of large debris particles (between 50 and 140 microns) as well as small particles (∼ 5 microns) that deteriorates the efficiency of delicate optics.

Condensable Supersonic Jet Facility for Analyses of Transient Low-Temperature Gas Kinetics and Plasma Chemistry of Hydrocarbons

LEMPUS-2 facility is designed and built to study processes of cluster formation and plasma-chemical reactions that include atoms, molecules, and clusters, in supersonic jets. The facility is equipped with modern diagnostics tools and molecular-beam, electron-beam, mass-spectrometer, spectrometer, and laser systems for testing and fine-tuning technological processes in a laboratory environment. One of the key advantages of the discussed facility is that in a single system and a single experiment, it combines the tools for the activation of transient and steady-state supersonic flow with self-sustaining or nonself-sustaining discharge, and flow analysis using electron-beam spectroscopy and molecular-beam mass spectroscopy. Dry roughing and high-vacuum pumps enable accurate diagnostics of chemically reacting processes in virtually any gas mixture, including hydrocarbons. A pulsed flow regime controlled by developed in-house fast valves provides an efficient way to examine quasi-stationary flows at fairly high flow rates, with significant material and energy savings. The facility serves a number of purposes, from cluster-surface interaction studies with thin film and surface structure formation, to high-pressure jet expansions that emulate spacecraft nozzles at high altitudes, to technological process development, primarily focused on hydrocarbons. Details of key applications of the facility are presented that include the gas dynamics of cluster jets, the formation of heterogeneous clusters, the study of plasma-chemistry of hydrocarbons, and the thin film deposition.

Analysis of whole human blood for Pb, Cd, Hg, Se, and Mn by ICP-DRC-MS for biomonitoring and acute exposures

We improved our inductively coupled plasma mass spectrometry (ICP-MS) whole blood method [1] for determination of lead (Pb), cadmium (Cd), and mercury (Hg) by including manganese (Mn) and selenium (Se), and expanding the calibration range of all analytes. The method is validated on a PerkinElmer (PE) ELAN® DRC II ICP-MS (ICP-DRC-MS) and uses the Dynamic Reaction Cell (DRC) technology to attenuate interfering background ion signals via ion-molecule reactions. Methane gas (CH4) eliminates background signal from 40Ar2+ to permit determination of 80Se+, and oxygen gas (O2) eliminates several polyatomic interferences (e.g. 40Ar15N+, 54Fe1H+) on 55Mn+. Hg sensitivity in DRC mode is a factor of two higher than vented mode when measured under the same DRC conditions as Mn due to collisional focusing of the ion beam. To compensate for the expanded method's longer analysis time (due to DRC mode pause delays), we implemented an SC4-FAST autosampler (ESI Scientific, Omaha, NE), which vacuum loads the sample onto a loop, to keep the sample-to-sample measurement time to less than 5min, allowing for preparation and analysis of 60 samples in an 8-h work shift. The longer analysis time also resulted in faster breakdown of the hydrocarbon oil in the interface roughing pump. The replacement of the standard roughing pump with a pump using a fluorinated lubricant, Fomblin®, extended the time between pump maintenance. We optimized the diluent and rinse solution components to reduce carryover from high concentration samples and prevent the formation of precipitates. We performed a robust calculation to determine the following limits of detection (LOD) in whole blood: 0.07µgdL−1 for Pb, 0.10µgL−1 for Cd, 0.28μgL−1 for Hg, 0.99µgL−1 for Mn, and 24.5µgL−1 for Se.

Design of cold compressor systems in terms of operational and economical aspects

In the past, cooling at 2 K used to be an exotic application in large scale cryogenics. The required sub-atmospheric helium bath was established with the help of one of the following two technical approaches - rough vacuum pumping at ambient temperature or turbo compression at cryogenic temperature - ora combination of both. The aforementioned approaches are still being applied, but the optimum distribution between warm and cold stages is not always obvious. In the last few years, 2 K cooling became a new state-of-the-art in the fields of experimental and applied physics. Standardisation of the machinery and its control significantly reduced commissioning time which has clearly been demonstrated during start-up of refrigeration plants such as Fermilab and DESY. Thus, the technological readiness of cold compressors has successfully been proven. This paper presents criteria for the optimisation of a cold compressor system under operational and economical aspects depending on the required 2 K cooling capacity.

Advancement of atmospheric-vacuum interfaces for mass spectrometers with a focus on increasing gas throughput for improving sensitivity.

Ion sampling from an electrospray ionization (ESI) source was improved by increasing gas conductance of the MS inlet by 4.3-fold. Converting the gas throughput (Q) into sensitivity improvement was dependent on ion desolvation and handling of the gas load. Desolvation was addressed by using a novel slot shaped inlet that exhibited desolvation properties identical to the 0.58 mm i.d capillary. An assay tailored for "small molecules" at high chromatographic flow rate (500 μL/min) yielded a compound dependent 6.5 to 14-fold signal gain while analysis at nano chromatographic flow rate (300 nL/min) showed 2 to 3.5-fold improvement for doubly charged peptides. Improvement exceeding the Q (4.3-fold) at high chromatographic flow rate was explained by superior sampling of the spatially dispersed ion spray when using the slot shaped capillary. Sensitivity improvement across a wide range of chromatographic flow rate confirmed no compromise in ion desolvation with the increase in Q. Another improvement included less overflow of gas into the mass analyzer from the foreline region owing to the slot shape of the capillary. By doubling the roughing pump capacity and operating the electrodynamic ion funnel (EDIF) at ∼4 Torr, a single pumping stage was sufficient to handle the gas load. The transport of solvent clusters from the LC effluent into the mass analyzer was prevented by a "wavy shaped" transfer quadrupole and was compared with a benchmark approach that delivered ions orthogonally into a differentially pumped dual EDIF at comparable gas Q.

MEMS-Scale Turbomachinery Based Vacuum Roughing Pump

This study forms part of a program to develop a micro-electro-mechanical systems (MEMS) scale turbomachinery based vacuum pump and investigates the roughing portion of such a system. Such a machine would have many radial stages with the exhaust stages operating near atmospheric conditions while the inlet stages operate at near vacuum conditions. In low vacuum such as those to the inlet of a roughing pump, the flow can still be treated as a continuum; however, the no-slip boundary condition is not accurate. The Knudsen number becomes a dominant nondimensional parameter in these machines due to their small size and low pressures. As the Knudsen number increases, slip-flow becomes present at the walls. The study begins with a basic overview on implementing the slip wall boundary condition in a commercial code by specifying the wall shear stress based on the mean-free-path of the gas molecules. This is validated against an available micro-Poiseuille classical solution at Knudsen numbers between 0.001 and 0.1 with reasonable agreement found. The method of specifying the wall shear stress is then applied to a generic MEMS scale roughing pump stage that consists of two stators and a rotor operating at a nominal absolute pressure of 500 Pa. The zero flow case was simulated in all cases as the pump down time for these machines is small due to the small volume being evacuated. Initial transient two-dimensional (2D) simulations are used to evaluate three boundary conditions, classical no-slip, specified-shear, and slip-flow. It is found that the stage pressure rise increased as the flow began to slip at the walls. In addition, it was found that at lower pressures the pure slip boundary condition resulted in very similar predictions to the specified-shear simulations. As the specified-shear simulations are computationally expensive it is reasonable to use slip-flow boundary conditions. This approach was used to perform three-dimensional (3D) simulations of the stage. Again the stage pressure increased when slip-flow was present compared with the classical no-slip boundaries. A characteristic of MEMS scale turbomachinery are the large relative tip gaps requiring 3D simulations. A tip gap sensitivity study was performed and it was found that when no-slip boundaries were present the pressure ratio increased significantly with decreasing tip gap. When slip-flow boundaries were present, this relationship was far weaker.

Consequences of plasma disruption mitigation by massive gas injection on the ITER torus cryopumping system

The ITER torus exhaust pumping system is based on six primary vacuum cryogenic pumps, and a rough and regeneration pumping system that can pump the exhaust gases from the torus cryopumps to the tritium plant. Massive gas injection is a proposed concept to mitigate plasma disruptions in ITER. The present paper identifies the limitations and down-times of the ITER torus pumping system after a massive gas injection event. Deuterium, helium, neon, and argon injections are discussed. The resulting high pressure in the torus is leading to high mass flows and heat fluxes to the cryogenic pumps, resulting in a significant and rapid temperature increase of the pumping surfaces normally cooled at 5K. However, the consequences on the torus pumping system operation depend on the gas species and quantities injected. Finally, the regeneration of the cryopumps, the rough pumping of the torus, and the overall torus pumping system turnover time until vacuum and thermal conditions for the start of the next plasma pulse are initiated again are discussed.

Methods of Preventing the Spread of Zinc Contamination During Vacuum Processing

Radioactive zinc, 65Zn, was detected after a thermal vacuum process that extracted a desired product from articles out of a commercial light water reactor. While the facility is designed to handle radioactive materials, the location of the 65Zn was in an area that is not designed for gamma-emitting contaminants. A series of experiments were conducted to entrain the contaminant in an easily replaceable trap within the process piping. The experiments were conducted with increasing levels of complexity. Initially, a simple apparatus was developed to determine the effect of substrate temperature on the vapor capture, which was followed by experiments to determine the effect of filter pore size on pumping and trapping, and finally the interactive effects of both pore size and temperature were evaluated. The testing was conducted on a system that used a roughing vacuum pump using model and prototypic materials. It was determined that heating the substrate to nominally 200 °C resulted in effective trapping on the model as well as prototypic material.

Super‐atmospheric pressure chemical ionization mass spectrometry

Super-atmospheric pressure chemical ionization (APCI) mass spectrometry was performed using a commercial mass spectrometer by pressurizing the ion source with compressed air up to 7 atm. Similar to typical APCI source, reactant ions in the experiment were generated with corona discharge using a needle electrode. Although a higher needle potential was necessary to initiate the corona discharge, discharge current and detected ion signal were stable at all tested pressures. A Roots booster pump with variable pumping speed was installed between the evacuation port of the mass spectrometer and the original rough pumps to maintain a same pressure in the first pumping stage of the mass spectrometer regardless of ion source pressure. Measurement of gaseous methamphetamine and research department explosive showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. Beyond 5 atm, the ion intensity decreased with further increase of pressure, likely due to greater ion losses inside the ion transport capillary. For benzene, it was found that besides molecular ion and protonated species, ion due to [M + 2H](+) which was not so common in APCI, was also observed with high ion abundance under super-atmospheric pressure condition.

Development and Characterization of a Field-Deployable Ion-Trap Mass Spectrometer with an Atmospheric Pressure Interface

A field-deployable quadrupole ion-trap mass spectrometer with an atmospheric pressure interface is designed, built, and characterized. The instrument enclosure (48 cm × 43 cm × 42 cm) includes a roughing pump and a helium lecture bottle; the total weight of the instrument is 68 kg. Peak power consumption during the instrument operation is ∼500 W. The instrument has a mass range of m/z 30-2500, across which it provides better than unit mass resolution. The typical peak width at half height is 0.3 Th for a scan speed of 4000 Th/s. Operation of the instrument with electrospray and atmospheric-pressure matrix-assisted laser desorption ionization (AP-MALDI) ion sources is demonstrated. AP-MALDI analysis of low femtomole amounts of peptides reveals that the sensitivity of the instrument is on par with modern commercially available quadrupole ion-trap mass spectrometers. Tandem mass spectrometry capabilities of the instrument include simultaneous isolation and fragmentation of several different compounds. Two ways to reduce the size, weight, and power consumption of the portable instrument were explored, and results of these initial studies are presented. One of the ways includes utilization of hydrogen as a buffer gas for operation of the ion-trap mass analyzer in combination with a metal hydride method for storage of hydrogen in a compact rechargeable cartridge. Furthermore, careful selection of the inlet capillary dimensions allowed to eliminate the first "1 Torr" stage of the differential pumping without any significant loss of the instrument sensitivity. The elimination of this first pumping stage removed two turbo drag pumps, which substantially decreased the instrument's maximum power consumption (to ∼300 W in peak use, and ∼150 W during standby), as well as its size (to 30 cm × 43 cm × 50 cm) and weight (to 35 kg).

Electron bombardment of films used for reducing spurious charge in electrostatic electron optics

In electrostatic electron optics charging on the surfaces of insulators separating the electrodes can cause undesired beam fluctuation. In prior work, the authors showed that coating the insulators with a film deposited by atomic layer deposition (ALD) could lead to acceptably low charging effects in the reflection electron beam lithography system. However, the stability of the resistivity can also be affected by contaminants present in the vacuum environment of the electron beam tool. The mechanism of formation for carbon layers typically involves the cracking of hydrocarbon contaminants adsorbed on the film surface by photon, electrons, or heat. This work describes changes in resistivity of ALD films of zinc–zirconium oxide and tantalum–niobium oxide 40 nm thick under different operating conditions. In a vacuum system utilizing an oil rough pump and a turbo pump, <0.01 C/cm2 bombardment with 309 V electrons results in about 1 order of magnitude reduction in surface resistance. This effect was not observed in an ion-pumped system suggesting that carbon contamination is the culprit. XPS measurements confirmed this suspicion. Improved results on a new material under development are presented.

Design and construction of a low‐cost economical thermal vacuum chamber for spacecraft environmental testing

PurposeThe purpose of this paper is to describe the design and construction of a custom‐built low‐cost thermal vacuum chamber (TVC) for spacecraft environmental testing and verification. The paper provides detailed analysis and an insight into the design and development of the chamber. The chamber was specifically constructed for carrying out the thermal and vacuum environmental tests in a 16″ dia × 16″ long horizontal thermal vacuum chamber. The chamber is constructed using a combination of mechanical (roughing) pump and turbo‐molecular pump, used to pump the chamber down to 10−5 Torr and a combination of radiation heaters and nitrogen gas is used to vary the temperature within the chamber from +80 to −50°C.Design/methodology/approachThe TVC equipment is built as part of the picosatellite and nanosatellite program at Space Systems Research Laboratory of Saint Louis University. The equipment is built at a low cost and is suited for testing an entire picosatellite and several components and subsystems of nanosatellite simulating thermal and vacuum conditions similar to space environment. The different main parts of the equipment are described in a way which explains the choice of construction and partly makes it possible to replicate similar equipment.FindingsThe TVC equipment is successfully used to simulate the thermal and vacuum conditions of space similar to the conditions experienced by a picosatellite or nanosatellite in low earth orbit.Research limitations/implicationsThe design and construction of TVC in this paper have broader implications and can be a platform for future research on low‐cost TVC. This equipment can be utilized in the research areas of electronics and communications, biology and medicine to name a few. Thermal and vacuum experiments on several astro‐biological experiments can be performed.Practical implicationsThe paper is intended to be a source of inspiration for industrial or academic space research laboratories which would like to design and construct a similar test‐equipment, instead of investing expensive commercially available alternatives.Originality/valueThe paper discusses in detail, the simplified cost‐effective approach of constructing TVC and also outlines the various issues to be considered. The TVC equipment is custom‐built and is described in an easily understandable way, which makes this a helpful paper for those who wish to produce similar equipment. This will be the only known manuscript in the literature to detail the design and construction of low‐cost, economical TVC.