High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
Michael Bretti
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Richard Hull,

Yes, noise shielding is certainly a major issue with high peak-power pulsed systems. Fortunately I have directly worked with active shielding and noise suppression for electronics and instrumentation around these types of pulsers. It is a challenge, but I have dealt with it before very successfully. One of the systems I actually built for work was a 90kv Marx generator to simulate electron gun arcing faults specifically for EMP and noise shielding for sensitive electronics around the fault. My goal is to develop the pulsers to work successfully with my pulsed e-gun setup, then migrate it over towards pulsed neutron work later (the e-gun setup would be less costly due to the fact that no expensive gas or gas handling is needed.)

Activation analysis was actually the main method of detection I was planning on implementing for the high peak power fast-pulsed systems, and I look forward to the design challenges and getting to that stage of testing.
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Richard Hull
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Richard Hull »

The one thing about activation; it is the only warranted noiseless, absolute indication that thermal neutrons had been there. As you note, calibration can be tricky, but with good math and the knowledge to apply it, calibration can be very accurate. You will just need a good averaged flux over time. From this, based on the pulse peak voltage and current, the flux per pulse should be easily computed.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Michael Bretti
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Richard Hull,

Thank you for your advice. I also just finished reading that new PDF you posted on activation - really fantastic introductory paper on activation, I greatly enjoyed it and it was very helpful, especially the section at the end explaining different target materials for activation. I was planning on starting with silver, and seeing this list of additional elements to explore has given me some new ideas for experimental test stand development that I think would be very exciting to build and share with the fusor community. Although I won't get to activation for a long time, I can certainly start working on gathering the necessary information and designing the various detector systems.
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Richard Hull
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Richard Hull »

Silver might have been #1 in my list and it certainly is the most common activated material here at fusor.net over the years.

Rhodium was #1 simply due to the raw data related to it, my own experience with it, and the fact that Enrico Fermi used it all through his work that lead to his Nobel Prize. He was forced to use made-up sources for his neutrons,(radium-beryllium), to calibrate and quantify them, he needed a fast activation element to 100%. Rhodium was ideal.

I had a friend who wisely purchased a 1 ounce bar of Rhodium, a short while back, when its price plunged to $700 per ounce. I contemplated it back then, but waited too long and the price soared again. As noted 1/10 ounce bars are available.

In my activation of my friend's bar, I was pleased that it exceeded silver in activation and that it took only 4 minutes to fully activate to 100% of its attainable radioactivity with a given flux!

As an ideal activation element it will forever remain #1 on any and all lists with only its crippling purchase price being its sole impediment.

Again........

100% of its atoms are ready to activate as it is a single isotope element. Its capture cross section is high and the finished radioactive product has a short half life, meaning weak and limited neutron sources can be rapidly checked out and quantified.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Michael Bretti
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

New update on the V4 System build. After additional planning and design, I have settled on a table I will be using for the system. Below is a CAD model of the proposed design:

System V4 Dual Purpose Table Assembly - V4 Chamber.png

The experimental table consists of a 2'x2'x3' structure made from 80/20 10 series extrusion. The 80/20 was purchased off ebay for half its original price won during surplus lot auctions. I ended up getting both black anodized and silver 80/20 since that was what was available for cheapest in bidding lots, and arranged it to have at least a symmetric and pretty cool look color-wise. I was originally going to go with a 2'x2'x2' table, however after discussing this project and another vacuum system project with one of my friends, he suggested to save money by combining the infrastructure of the two systems to support both. After some careful planning and design, I have been able to come up with a low-cost solution to support both systems simultaneously. Only the 2.75" conflat based system is currently shown in the model. The roughing pump is in the center, laying on the floor to minimize vibrations transferred to the rest of the structure, but still keeping it within the build volume. There will be ample space for the power supplies, diffusion pump chiller, baffle chiller, and other control electronics. An additional 6" KF25 bellows line will be needed to connect the roughing pump to the main roughing line under the foreline trap.

The second system is based around a 6" conflat tee that I obtained for free. This system will be used for ion and plasma engine testing. Last year I had originally bought a very large 6" throat gate valve/butterfly valve combo for the 21 port custom conflat system I posted about a while ago, which after looking at the logistics to get operational, was recently sold. I also obtained an 8" water cooled baffle for the original system as well. Both the baffle and the valve were $100 each, and in excellent condition. Since I already have another Edwards EO4 diffusion pump, as well as the baffle, gate valve, chamber, and basic feedthroughs, all that is really needed are the two aluminum adapter plates to fit everything together. I was going to build a completely separate system for this setup, but since the diffusion pump is the same as the V4 system, it was decided to extend the table to accommodate this test chamber as well. I will end up splitting the roughing line symmetrically to feed into both diffusion pumps, as well as route cooling for both diffusion pumps and baffles to run off the same cooling system. I will only run one system at a time, never both simultaneously, so in my control architecture I will make accommodations to switch between pumping and cooling for both systems. Initially, this second system was planned for operation years down the road, however using this shared setup, I will be able to deploy it and start testing it in a much shorter time-span, since the infrastructure will already be built and shared from the first system. The cost savings implementing this shared topology is on the order of $2k or so. I will post an updated CAD render of both systems mounted with the proposed roughing line upgrade shortly.

In terms of the actual physical build, the 80/20 has already been ordered and arrived. The remaining hardware is coming in today. I have also already started modeling the chiller block subsystem of the diffusion pump cooling system. The main heat exchangers will be arriving within a week. Once this chiller is qualified, then I will proceed in building a second chiller for the baffles. I will also post design specs of the chiller as I progress further, but I have most of the parts already for the chiller block.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Bit of a sudden and unforeseen setback to the above plan. Upon completing the 80/20 table, I decided to open up one of the two hermetically sealed boxes that, when I received them along with the open diffusion pump, was told they were new, unopened pumps. The boxes were the same dimensional size and weight as the EO4 diffusion pump. However, it turns out that they were nothing more than very large circuit breaker boxes. They were such old pieces of equipment from decades ago it was forgotten what was in them and assumed to be pumps. Turns out I only have one instead of three diff pumps that I initially thought I had. Rather disappointing considering a large portion of future systems relied on the requirement of having multiple of the same diff pumps. However I am still quite happy that I have even one diff pump in new condition. I could still proceed to mounting the second chamber since I have most of the parts anyway, but running it will have to wait for now, since the small chamber is priority.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Quick build update. Most of the 80/20 table has been completed over a week ago. Still leaving some of the center support beams off until I actually start mounting equipment:

20180519_214150-1.jpg

The design of the chiller system has just about been finalized, and almost all of the remaining parts have been ordered. Many of the parts were ordered on eBay from overseas suppliers to save cost, so they will take over a month to get in, but that gives me plenty of time to work on other system designs. I am currently working on the cad model for the final design of the chiller subsection, which will be posted when completed. Its current specs are rated so far for around 1200W cooling capacity (1000W air-liquid heat exchanger capacity, and an additional 200W liquid-liquid heat peltier chiller capacity.) As described before, it is a triple-loop, closed loop peltier based chiller. The EO4 diffusion pump works optimally with cooling water at the inlet in the range 15C-25C (max), up to 850W of power. The entire chiller will be mounted to a 2'x2' MDF panel that will be mounted vertically to the back section of the table. The system will utilize 4 thermocouple gauges, mounted at the diff pump inlet, outlet, in the main water storage tank, and the secondary storage tank for the peltier heat exchanger subsection, in addition to a water flow meter. All three pumps used in the system will be PWM driven and modulated based on temperature readings to keep precise temperature control of the system, and controlled through an Arduino Mega.

I also have left space in the design for future upgrades to be able to double the entire cooling capacity of the chiller to around 2400W to be able to support my second larger high vacuum system for ion engine testing. Both of these systems will share the same cooling and roughing infrastructure to significantly reduce costs of having two operational systems. I have been able to secure an even larger diffusion pump in practically new and unused condition for free for the ion engine test stand, and as a result, this pump will require much more cooling capacity (with the temperature range at the inlet the same as the EO4). I will be posting details of this second build in a new post specifically for that system.

One final note. In addition to the new diffusion pump, I have recently acquired an incredible piece of physics equipment that will allow me to experiment with charged particle beams at energies and peak power levels unlike anything presented on these forums here so far. If I am successful with this new system design and rebuild, it will be, as far as I am aware, the highest energy and peak power charged particle beam system currently built and operated at the hobbyist level. In addition to this component, I also obtained supporting vacuum flanges and pumps to run it. I will post more details of this new, third system in a different forum topic, but its potential can bring about an exciting new level of physics research at the hobbyist level.
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Dennis P Brown
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Dennis P Brown »

If your high energy charge particle device is so powerful, then you had better be aware of the x-ray hazard and be certain of your shielding.
Michael Bretti
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Yes, I am fully aware of the hazards, particularly with xrays. This device will not be operational for quite a while, so it will be a long term endeavor. I also work at a nuclear research facility so I have plenty of experience with radiation hazards and training. I also directly work with these devices regularly, and am well versed in their operation. I spent over a year almost exclusively working on various pulse power drivers for one, so this is by no means a typical amateur project.

I will be rebuilding it for a different mode of operation than its current configuration. It will only operate at very low repetition rates of a few hz at most, at only several nanoseconds in pulse widths. However I am looking at ultimately reaching the 1MeV barrier, with peak power levels of hundreds of MW at the nanosecond timescale. Not sure if I can drive 1MV across it yet, but I should be able to very readily achieve hundreds of kV without issue. I am already working on the preliminary specs for the pulse power driver for the rebuild. I will release more details later in a different post.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

New update on the cooling system build. I have finally finalized the CAD designs and layout for the system. I have posted a full overview description as well as system specs, which can be found in the link below. I plan on eventually adding the engineering drawing sheets for all of the components, as well as datasheets for the parts used in the build:

http://appliedionsystems.com/portfolio/ ... p-cooling/

Just wanted to share a few of the CAD models for the proposed design. The first is the actual peltier chiller block. This is the second loop of the triple-loop system, where water is continuously flowed through the chiller from and to the tank. The cooled water mixes with the incoming water at the end of the first loop from the heat exchangers after the diffusion pump, which will help for better temperature control. The chiller block consists of five TEC1-12708 peltier modules sandwiched between two aluminum water cooling blocks - one for the hot side, and one for the cold side. The hot side features three solid copper heat sinks with integral cooling fans for initial heat extraction, where an additional 500W air-to-liquid heat sink removes the rest of the heat before entering the secondary storage tank:

Peltier Chiller Block - Resized.png

The next picture shows the full assembly of the chiller block. This includes 1" thick XPS insulation foam on the cold side, and HPDE plates to hold the assembly together. All thermal interfaces between heat sinks and peltier devices will use Arctic Silver 5:

Peltier Chiller Block Assembly - Resized.png

The next renders show the full assembly positioned on the 24" x 36" x 0.5" MDF board. Unfortunately a lot of the components have varying inlet sizes, so several different tube sizes and adapters were needed to mate everything together. The tubing consists of various sizes of opaque black EPDM, rated for -40F to 300F. This model took quite a while to finalize, as there were a significant number of hoses and connections to position and mate. However, it has let me fully plan out the system before the build. As mentioned above, the system has space and contingency built in for a future upgrade to double its heat handling capacity from 1200W to 2400W. Right now the estimated power consumption at nominal operation is expected to be around 450W:

Cooling System Assembly - Top View.png
Cooling System Assembly - Isometric View.png

Finally, the full cooling assembly is mounted to the 80/20 experimental stand with the V4 high vacuum system and roughing line:

System V4 Dual Purpose Table Assembly - V4 Chamber with Cooling System.png

So far, everything is falling into line well with the design. It should make for a compact but highly controlled and modular system. The cooling system has admittedly cost more than I had initially wanted, but it is best to plan and invest in a solid system now that can handle all of my needs for any vacuum projects in the foreseeable future. Since the roughing line and cooling system will work for both diffusion pumps I have, with a couple of aluminum adapter plates I can quickly and easily change between the three high vacuum chambers I have for testing, which saves a significant amount of money for the future, and provides me a robust experimental test stand design that will allow me to run all of my physics experiments for years to come. I have obtained all of the hardware to start the build, so I will be working on the actual cooling system in the next few weeks. I hope to actually do some test runs, as well as do thermal imaging to analyze the response and performance of the system. I will also be starting to work on the control software for the cooling system, which will be used to set several interlocks for the main diffusion pump power based on the system temperature and flow rates.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

A few updates on the cooling system, control system, and overall direction of this project.

For the cooling system, the secondary tank capacity was increased a bit from the initial design. I had originally spec'd a 3"x10" pvc tank. However, since I was already using 4" pvc for the main tank and had some leftover, I decided to just increase the secondary tank capacity to a 4"x10" tank which takes up negligible extra space overall. Fill ports were also added to each of the tanks. Second, since I have purchased the main heat exchangers as sets of 2 for a great discount on eBay, I ended up with an extra leftover from my previous purchase. I will be adding this to the design to bring the primary cooling loop capacity up from 1200W to 1700W, which would allow me to run this cooling system now with either of my diffusion pumps. The contingency for this upgrade was already built in, so I figured I would add this now for minimal additional cost.

For the control system, as mentioned above, I will be going with an Arduino Mega microcontroller. Since I don't want to spend a massive amount of time creating my own fully custom GUI from scratch, I decided to look into several available solutions. The ones I initially researched and considered include the following:

1.) Azande - https://zeijlonsystems.se/products/azande/index.html
2.) MegunoLink - https://www.megunolink.com/?nabe=6011995085340672:1
3.) Instrumentino- http://www.chemie.unibas.ch/~hauser/ope ... index.html
4.) Makerplot- http://www.makerplot.com/

After a lot of looking into each of the options, researching their capabilities, evaluating my system requirements, and weighing their strengths and weaknesses, I have decided that I will most likely being going with MegunoLink. Azande and Instrumentino are both free, while MegunoLink and Makerplot go for about $40 each. I like both MegunoLink and Makerplot, and feel they both have a lot of powerful and robust capabilities to offer for monitoring, data logging, and control with the Arduino. However, based on my system, I feel that MegunoLink would be the best option for my needs. Now that I have the basic overview of the initial inputs and outputs for my control system, I will start coding up the controller, and probably download the free trial version first and experiment with it before I pull the trigger. The initial system inputs for monitoring and plotting will include the four thermocouple sensors for the cooling loop monitoring, the flow sensor, as well as a digital temp/humidity sensor for ambient monitoring, the roughing side thermocouple gauge, and the high-vacuum side wide range transducer. Outputs will need to control pwm for speed control of the three cooling pumps, as well as a 16-channel relay board for turning on and off the numerous heat exchanger cooling fans, water pumps, peltier modules, and interlocks for the diffusion pump main power, and other power and electronics needed for the system. Semi-automated to full automation of pumpdown is still expected, as well as real-time monitoring of all system and environmental parameters, in addition to data-logging system conditions each run and pumpdown to build up a log of run data to better control and understand the system.

In terms of the overall experimental direction for this build, I have decided on the first experiment and system that I will be concentrating on, and the main focus of my research going forward. This build will initially support a 300kV, 30MW peak-power nanosecond-pulsed electron gun for intense relativistic pulsed electron gun injector development, initially exploring scattering and transmission studies in open-air. The preliminary system cost analysis, gun design, Faraday cup, and extraction window are already in the initial design phase. This build will be used to support a much more high-power and ambitious system build in the future, and is a moderate stepping stone towards my ultimate goal. In addition to research into this rather unique and highly-specialized subset of the highest peak-power class of electron gun injectors in use for physics research (which usually reach in the many 10s of GW range for peak power), this build can also be used as the first starting point to support intense ion-beam development, which opens up the door for a lot of exciting, more high-energy experiments than normally done at the hobbyist level. However, electron beam work will be the primary focus, since I will not have to worry about the cost of gas handling subsystems for ion injectors.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Quick update on the cooling system build. The primary and secondary water tanks have been completed and assembled. Attached to the tanks are the thermocouple gauges, as well as fill ports at the top, and brass hose fittings for the cooling lines. A couple of additional ports were added as mentioned prior for future cooling capacity upgrades, which are currently capped off. No pvc glue was needed either for the pipe to end-cap fitting - it turns out that the standard 4" pvc to 4" clay pipe rubber adapters with hose clamps works perfectly between the pipe and cap interface, and provides a leak-tight seal that also allows me to completely disassemble the tanks if I ever need to get inside them in the future. Now that these are done, I can start mounting them to the MDF baseplate. Once these are on, then the rest of the cooling system mounting is pretty easy. The tanks have already gone through preliminary leak checking, and should be good to go.

Cooling Tank Pic 1.jpg

Cooling Tank Pic 3.jpg
Michael Bretti
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Another update on the cooling system. In my initial designs, I forgot a key parameter that has forced me to redesign the whole system from scratch. While mechanically and thermally the system was sound, chemically it was not. In my cooling loops, I had brass, copper, stainless, and aluminum. These metals in combination would induce galvanic corrosion over time. There are coolants that can be used for combination metals in loops, specifically inhibited glycol coolants. However, it also turns out that glycol, both ethylene and propylene, are not compatible with pvc, which my storage tanks are made from, and will eventually degrade pvc on contact over time.

However, it turns out that this initial issue, and subsequent redesign, has been the best thing to happen to the cooling system yet. Upon re-evaluating my options, and re-configuring the system, for only a little bit more in expenditures, I could radically improve and upgrade performance of the whole system in all aspects, and selected components that would make it much easier to build. The pvc cooling tanks were replaced with larger capacity hdpe tanks with integral mounting flanges. This increased the tanks capacity by 2.5x in a smaller amount of space. These tanks were purchased for $8, and are very robust. The primary and secondary loops, which share coolant, have only copper/brass components, and the third loop, for cooling the peltier hot side, will reuse all the aluminum cooling parts I had bought previously, and since it is an isolated loop, will not have corrosion issues. To replace the aluminum heat exchanger on the primary side from the initial design, I got a 7kW rated copper heat exchanger used for furnaces from ebay for only $30. The secondary loop, consisting of the peltier chiller block, will use an array of high quality solid copper heat-sinks scavenged from disposed servers, with coolant flowed between the fins. 8 peltiers will be used for this chiller block. Solid copper heat sinks with integral mounted fans also scavenged from servers will help cool the hot side aluminum blocks as well, three for each block. The aluminum cooling blocks will be doubled up on the hot-side as well, with an extra heat exchanger running in parallel. Two 1750 CFM performance radiator fans for cars were purchased from ebay for $25 each for cooling the main heat exchangers. In all, the heat capacity specs for each of the loops are as follows:

1.) Primary Loop (diff pump main heat exchanger) - 7kW
2.) Secondary Loop (peltier chiller block) - 300-400W
3.) Tertiary Loop (peliter hot-side cooling) - 1kW

I have most of the components needed to actually start building the cooling system, and will begin construction shortly. I will post pictures and further updates as I progress. This system should now be far more than enough to handle any heat load needed for any future experiments, and should last me indefinitely. Once this is complete, I will qualify it with my thermal imaging system, then proceed to writing the code for the automated control and monitoring system.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Quick update on the cooling system build. Below is a picture of the V2 system so far:
Cooling System Update - Front.jpg
Cooling System Update - Back.jpg
I currently have all of the hardware needed to complete the system, it is just a matter of finishing up some of the custom components. All brass hardware that was originally to be used has been replaced with much lower cost nylon components, which has more than wide enough temperature range as well as chemical compatibility for this build. In parallel with this build, I have also been working on rebuilding the thermocouple sensors I purchased for cheap on ebay, making them both waterproof and corrosion resistant with new 316 SS casings, and mounting them to the custom adapters needed for placing them in the system, as well as qualifying and calibrating their response. It turns out that the original sensors I bought were not actually SS, and a quick immersion test in water revealed rusting within hours, necessitating a rebuild of the sensors.

I am also about half way done with the upgraded peltier chiller module, which still requires custom machining some nylon manifold blocks for directing flow through the chiller, as well as a couple of other nylon manifolds needed for directing flow to the tertiary loop heat exchangers. Once the rest of these custom components are built and mounted, I can proceed to routing all of the cooling lines and bolting the assembly to the 8020 table. All three of these builds, (the thermocouple upgrade, the peltier chiller, and the completed cooling system) will have full and complete documentation available including cost analysis, components supply, specifications, CAD drawings, testing and calibration data, and full build walkthroughs. I will release links to the pages with this information as it is completed. I expect to finally complete the entire cooling system and have it qualified and tested with my thermal imaging camera within the next few weeks.

In parallel with these efforts I have been working on the pulsed power driver for the first intense e-beam system. The small multipurpose V4 vacuum system will implement a small, lower power beam to qualify intense beam transport through gases, as well as the first stage of the pulse power unit. Details of this build will follow after the cooling system is complete. For this system, I have obtained a large supply of large 28kV, 0.02uF pulse capacitors used for the primary stage of the driver. So far I have tested up to 2 capacitors in parallel into a dummy primary pulse transformer load, achieving a current of 1164A @ 23kV charging voltage, for a total peak pulse power of 26.77MW in about 1uS FWHM. I plan on using 8 parallel capacitors for the small system, and 16 for the large system I am working on. For the small gun, which will only be driven by the first slow stage of the pulse power driver, I expect input power into the gun in excess of 100MW, with gun efficiency of several 10s of percent. With additional pulse compression I expect to easily achieve much higher peak powers. Once the small gun has been qualified and running with the primary pulse power stage, then construction on the large gun will begin with the full pulse power unit.
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

A big update on the vacuum efforts so far. The cooling system is finally assembled, mounted to the test table, and all of the cooling lines routed. It has been a challenging and demanding design and build process over the past couple of months. Now that it is assembled, the next phases of writing the control code, wiring the electronics, and qualifying the system can begin.

The system should be able to support both of my diffusion pumps - my 850W EO4, and my 1450W NRC. My three major vacuum setups - the small-scale V4 system, the accelerator build, and the micropropulsion test chamber will all share the same infrastructure, and are designed with adapter plates that will allow me to rapidly switch between test setups with ease, reducing the overall cost of having multiple systems to one modular, inclusive test stand. I will post details of the other builds in other forum posts. I also have full documentation available for all of my builds, including engineering specs, datasheets, CAD drawings, CAD files, cost analysis, and build pictures. I have a lot of documentation left to organize for the full cooling system build, and will release the links when complete. For now here are the links to the peltier chiller module build and the thermocouple build:

http://appliedionsystems.com/portfolio/ ... er-module/

http://appliedionsystems.com/peltier-ch ... -pictures/

http://appliedionsystems.com/portfolio/ ... d-upgrade/

http://appliedionsystems.com/low-cost-t ... -pictures/

Here are a couple of pictures of the cooling system. Thermal imaging data to follow:

Completed Peltier Chiller Cooling System 1.jpg
Completed Peltier Chiller Cooling System 2.jpg
Michael Bretti
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Full technical specifications, CAD files, cost analysis, build pictures, and a detailed overview comparison article between the iterations of the cooling systems are now available for the peltier-based chiller for diffusion pump cooling system:

http://appliedionsystems.com/portfolio/ ... p-cooling/

http://appliedionsystems.com/closed-loo ... -pictures/

http://appliedionsystems.com/learning-f ... -redesign/
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Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

New update on the cooling system build. I finally completed the first round of preliminary testing this week, and have analyzed the data and calculated all the major thermal parameters of the system. So far, it appears that it is performing grossly under spec - however, I have traced the problem back to the heat exchangers, which both use the same fan. It appears that the fans do not push nearly enough air through the heat exchangers, greatly reducing their ability to dissipate heat. I am in the process of replacing these with high static pressure fans that should fix this issue. Fortunately, since my system is so heavily instrumented (now 6 thermocouples, 3 flow sensors, and a general ambient temp/humidity sensor), debugging and analyzing system performance is quite easy. I also downloaded my free trial of MegunoLink to start seeing if it is a viable option for control and data logging. So far I really like the software, and was able to set up real time plotting and data logging in a only a couple minutes with my Arduino Mega, which was used for collecting the data for the test. I will be working on building the entire control system, which will be housed in a large computer casing mounted to the side of the 8020 test stand, and includes all of the power supplies, circuitry, and instrumentation cards for the high vacuum and cooling systems. Full details of the first round of testing and data analysis can be found here:

http://appliedionsystems.com/preliminar ... ng-system/

After the testing was complete, I also made the discovery that my small water cooled baffle that I was originally going to use for the EO4 diff pump is made from plated steel, not stainless steel, and had heavily rusted inside. As a result, I will not be using that baffle anymore, and will instead switch to using my larger 8" water cooled baffle, which I was originally saving for the NRC 0183 diff pump. This requires designing new adapter plates, which I will make so that both diff pumps can be used with the baffle, as well as all of my test chambers. While it does make the system even more modular as a whole now, it does add an extra expense that will delay pulling vacuum for a while, but I still have plenty of work to do in terms of documentation, CAD, testing, and coding the automated control system.
Michael Bretti
Posts: 175
Joined: Tue Aug 01, 2017 12:58 pm
Real name: Michael Bretti

Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

Another quick update on the project progress so far, and the scope going forward. The cooling system is about complete and almost ready for final testing, and is currently being integrated with the new control system I am working on. The control system hardware is being assembled, and is in the process of being wired together. Due to the extremely high peak power pulses I will be generating for one of my systems, I have decided to keep the control box separate from the main test stand, which relaxes EMP shielding requirements on the box. The project itself has evolved and expanded immensely since I first started, and has been rapidly gaining much more sophistication than I even previously first planned.

For the control system, I have decided to fully embrace MegunoLink (https://www.megunolink.com/) for developing the user interface and control architecture on the Arduino Mega. I have been working with it more and more in the past week and a half, and have come to really like the program. I keep finding new features to implement, and it has proven itself to be a very powerful and capable piece of software, and has really allowed my control system to explode in sophistication and features. Currently I have full data acquisition complete and running, which allows me to graph and save all the data for my cooling system sensors, as well as the roughing gauge and high vacuum gauge in the chambers. I am now working on implementing all of the controls for manual mode operation, which will allow for individual control and adjustment for every component in each of my subsystems (cooling pumps, fans, peltiers, vacuum pumps, etc.), and will be moving on to the automated safety interlocks, and a full automation mode, which will allow my system to run through the complete cooling and vacuum pumpdown cycles automatically with the single press of a button.

The original V4 design has also evolved, with the introduction of the new 8" baffle and adapter plates to replace the original smaller baffle that has rusted. Since I started working on a couple of new larger scale vacuum systems that are now higher priority, the small-scale V4 system is also currently on hold for the foreseeable future. However, the two large systems will still be using the entire infrastructure I have built up so far, including the 8020 test stand, updated cooling system, roughing system, diffusion pump, and control system.

As a result, I will probably start a new forum topic on updates going forward, since the project has rapidly evolved beyond the initial scope presented at the beginning of this post series. The new topic will continue from here, looking at the current status of the fully integrated cooling, vacuum, and control system that will be used to support all of the chambers that I am working on. I will also be introducing the two larger systems I am working on that will be used with this test stand as well, although the full details for the projects will be beyond the scope of this forum, and include a tremendous amount of engineering effort that would be inefficient to try and post here. The full details and technical documentation however will be available on my website as I progress forward with them.
Michael Bretti
Posts: 175
Joined: Tue Aug 01, 2017 12:58 pm
Real name: Michael Bretti

Re: High Vacuum Engineering Design, Analysis, and Build of a Small-Scale Multipurpose System

Post by Michael Bretti »

As of today, the Small Scale Multipurpose V4 system design is obsolete, and I have moved to the newest V5 version update. This update is to adapt the system to the newly designed high vacuum pumping assembly and utilize the highly modular design of my pumping station to its fullest. This update allows the small 2.75" chamber to adapt to the 6" conflat port that I will be using for my propulsion chamber and large beam chamber. While I still won't be running any experiments with the V5 system for a while based on funding and project priority, I am still moving forward with planning and designing all of the experiments and finalizing them for when I can begin testing down the road. The new V5 system will be used to support researching scaled versions of the large, high power beam system I am working on, which I will post about more as I progress.

In addition to the V5 design, I have completed new thermal modeling simulations for the new baffle and diffusion pumping assembly, which I will create a new post for. I will also be starting molecular flow simulations for high vacuum operation with some new software that I found and am planning to explore further.

Below are the CAD render files of the new V5 design, as well as the V5 system attached to the upgraded diffusion pump assembly.

2,75in Conflat High Vacuum Chamber V5.png
2,75in Conflat High Vacuum Chamber V5 and Pumping Assembly.png
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