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What Is METALAST? METALAST developed a process control computer that implements a special pulsing technique to provide electricity to the parts in the anodizing bath. The METALAST process control computer implements alloy or part specific recipes to control the electrical output to the parts in the anodizing bath. Recipes are developed in a research environment to optimize the results for each run. By using computer control over the ramp-up, voltage and amperage in the process. METALAST achieves consistency and repeatability, while avoiding the tendency of parts to burn. The pulsing adjusts the way that the oxide builds through the interaction of electricity and chemistry. Parts don’t stay too long in the bath without oxide-build taking place. When oxide is not building on parts that are subject to electricity and acid, they’re under constant attack by the acid in the bath. So you’ve got to build an electrical pulse that dovetails with the oxide-build in order to prevent the tendency of the surface to dissolve in the acid. METALAST provides a chemical additive that is a complex organic compound. It is added to the bath to build a more efficient oxide which, in turn, provides a number of benefits. It builds the oxide with less dissolution of aluminum. It builds a tighter, denser pore structure. The "elasticity" it imparts to the surface resists cracking and crazing. And, it helps protect against something called "edge effect," which means that it forms better corners so that the oxide doesn’t fracture easily. That’s why it outperforms conventional anodizing in virtually all characteristics that are typically looked at, including, corrosion protection, abrasion protection, surface hardness, surface smoothness and lubricity. The advantages of the process improvements are enhanced by their integration into a complete technology. Today, METALAST offers the world’s only true anodizing "technology" to the marketplace. At their Minden, Nevada Tech Center, a full staff of scientists provide education, research, and technical support in both existing and new anodizing systems. In conjunction with the process automation and superior additive, they are able to work with manufacturer’s samples to provide unique and superior solutions to their needs for quality, consistency and performance. |
So, if they don’t have mass, how could they prove to be the missing 90% of matter that has yet to be identified? Theoretically, neutrinos could have mass, and Dr. Ayres and his colleagues around the world hope to prove that they do.
The Neutrinos Are Coming
Thus is the mission of the Main Injector Neutrino Oscillation Search (MINOS) experiment. MINOS will use Fermilab’s NuMI (Neutrinos from the Main Injector) beam to search for this phenomenon. Mechanical engineer Kris Anderson explains, "The real goal of this experiment is to look for neutrino oscillations. Something that oscillates has mass. Therefore, basic physics says that, if the neutrinos oscillate, they must have mass."
The Fermilab accelerator will be used to create a beam of neutrinos. To do this, scientists will first extract protons from their main injector. Then they’ll bend the proton beam downward in a beam line so that they hit a target that is made of graphite. At the point of impact, pions will be produced. Two focusing horns will collect the pions that spray off the back of the target. The first horn directs the errant pions into a column. Some distance away, the pions that are under or over focused from the first horn go through the second horn and get focused. Anderson describes what happens next, "At the end of the second horn we have what is called the decay pipe, that’s a two meter in diameter, evacuated pipe. It’s 650 meters long — there is nothing inside it. The pions that we’ve collected go through the decay pipe."
Then the objects of the experiment will appear. The pions decay into neutrinos. As mentioned, neutrinos go through anything, including the Earth. And you can’t steer the neutrinos because they have no charge. But, you can steer the pion beam before it decays into neutrinos. So once you have the pions on the right orbit or course, the neutrinos continue on in that course.
The focusing of these streaming particles starts 120 feet below grade in the aquifer under rural Batavia, IL. The beam is aimed at an evacuated iron ore mine 735 kilometers from Fermilab, in Soudan, MN, where the "far" detector for the MINOS project will be located. Because the neutrinos are traveling at the speed of light, it’s necessary to the experiment that they be given adequate time and space to oscillate into one of their three variant forms. At the beginning of their journey, the MINOS "near" detector quantifies and characterizes the neutrinos before any oscillations. Then the MINOS "far" detector in Soudan, does the same at the other end – after they oscillate. In this way, the experiment identifies the incidents of oscillation by detecting the neutrinos’ transformed from one of the variant forms to the others.
Bringing Science Down To Earth
Sounds like a great experiment. But making it happen isn’t so easy. According to Anderson, "Most of our experiments are done in tunnels 25 feet or so underground. But this one is much deeper. Typically they are not into the aquifer layer." Being in the aquifer could have disastrous effects on the reliability of beamline components used in the NuMI/MINOS equipment. The focusing horns control the direction of the beam. Any corrosion of the horns could cause a loss of pions and the failure of the experiment, which is expected to last for 10 years.
"There are two sources of dampness," explains Anderson. "The first is a result of the underground ambient conditions which are moist and wet. The second source of wetness is the cooling system." The horns are designed from aluminum because fairly high electrical conductivity is required (there is a lot of current that runs through them to make magnetic fields). Two hundred thousand amps of current pulse in 5 millisecond duration intervals through the inner conductors. Since there is some resistance associated with the material — the conductors get 17 kilowatts of heating from the pulses — the engineers designed a series of water spray nozzles to keep the conductors cool.
The ultimate solution to the moisture related problems was anodizing. Anodizing could protect the focusing horns from the otherwise inevitable corrosion. The anodizing also performs another function, as it is a dielectric barrier that provides voltage isolation important to the success of the experiment.
The horns will become highly radioactive from particle interactions on the target, and particles actually physically go through the conductors of the horn. Each time that happens, particles are knocked out from the lattice and the particles become radioactive. The horns’ coatings can not be affected or degraded by high radiation environments. The material has to be inorganic.
Searching For Anodizing Perfection
To identify the perfect anodization, they decided to benchmark some coatings. Anderson searched for anodizing vendors that had tanks that could handle large parts. In the end, he chose Universal Metal Finishing (UMF), Chicago, IL, not only because of their large capacity, but also for their numeric METALAST process control. He adds, "They ran our samples for us and helped us with the terminology of coatings. We selected a sulfuric acid Type III (1.8 mils to 2.3 mils thick coating) hardcoat anodize followed by a mid-temp nickel seal. The thinner coatings didn’t perform as well and showed some evidence of pitting. The thicker ones didn’t perform as well because, as you build a thicker oxide, it becomes somewhat porous."
Within the focusing horns, particles actually pass through the wall of the conductor. The particles that are passing through are pions. If it were a very thick walled conductor, those pions could re-interact with the aluminum and have secondary interactions and decay into other particles. In order to maximize pion collection, the conductor needs to be thin so that it’s somewhat invisible to the pions. It also has to be highly conductive to prevent current loss —another reason for selecting aluminum. Anderson estimates the service life of horn one to be 10 million pulses, which corresponds to more than one year of operation. "With horn two, the mechanical stresses are less and we are going to approach infinite reliability," he says.
Tight Tolerances Are Key To Success
Currently, UMF is anodizing the prototype of the first focusing horn. There are critical high current surfaces that need to be masked from anodizing because they are going to be silver plated. UMF will do the critically precise masking. The prototype focusing horn weighs about 650 pounds. Its outside diameter is 13.75 inches and the inside diameter is 11.75 inches. It is 124.29 inches long. The entire 6061 T-6 aluminum structure and coatings is held to tolerances of better than 10 thousandths of an inch. The inner conductor is coated with electroless nickel. Of course, the anodized coating thickness must be extremely precise.
The shape of the horn was proposed by Fermilab’s Russian colleagues at IHEP (Institute of High Energy Physics). In total, Fermilab intends to build a prototype horn, two production horn ones and two production horn twos. Initially there will be a total of five focusing horns. Horn one is smaller in diameter and a little shorter than horn two. They both have parabolic inner conductors that will be excited by a 200 thousand kiloamp pulse.
—KC
For more information;
Circle 521 - Universal Metal Finishing or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/012df-521
Circle 581 - Fermilab or connect directly to http://www.1rs.com/012df-581
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