tours:faq
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tours:faq [2016/03/31 10:20] constan [What are the advantages of a cyclotron over a linear accelerator?] |
tours:faq [2021/01/20 10:04] constan |
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| ===== Questions with Incomplete Answers ===== | ===== Questions with Incomplete Answers ===== | ||
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| + | ==== Fun facts about FRIB ==== | ||
| + | * Will be the world-leading rare isotope facility, with the most powerful heavy-ion beams | ||
| + | * Accelerates heavy ions to ~50% of the speed of light | ||
| + | * Produces rare isotopes that are radioactive and short-lived; never found on Earth, but stars make them! | ||
| + | * Is expected to discover ~1000 new isotopes (varieties of elements that have never been observed) | ||
| + | * Will serve over 1500 researchers from 50+ countries | ||
| + | * Facility consists of four buildings, 565,000 gross square feet | ||
| + | * Underground tunnel: 570 feet long, 70 feet wide, 13 feet high; floor is 32 feet underground | ||
| + | * Total Project Cost: $730 million, mostly funded by the US Department of Energy Office of Science | ||
| + | * Home to the #1 US nuclear physics graduate program | ||
| + | * Planned to come online in early 2022 | ||
| + | |||
| + | ==== Why is the cycstopper standing on end, rather than lying flat like the K500/K1200? ==== | ||
| + | //(from Stefan Schwarz)// Main technical reason: the cyc-stopper is better at accepting large beams (in terms of emittance, i.e. beam width times angle) in its axial = horizontal direction, as built. | ||
| + | A bit of background: for the beam to stop efficiently in gas stoppers, it needs to have less energy spread than what we typically get from the A1900. | ||
| + | |||
| + | To reduce that energy spread we use what’s known as momentum compression, i.e. the process of removing longitudinal energy spread with the help of a dispersive element (big dipole magnets in N3/4) and matched wedge-shaped degraders. However, since we bend/disperse the beam horizontally, the beam quality suffers in that plane. The cyc-stopper’s acceptance is higher in the horizontal direction when ‘standing’, so it’s able to make up for the larger beam emittance in that plane. | ||
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| + | There are also practical reasons: as built, the stopped beam will come out on the fixed south side of the magnet through the central bore. It’s a lot easier to construct an extraction beam line with this concept than taking the beam out through the top or bottom half in a ‘flat’ orientation. Also, access and work on the low-energy ion guides (carpets, conveyor) is a lot easier that way. | ||
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| + | FYI, we entertained the ‘flat’ orientation for a while in the early design phase, but for the reasons outlined above, we gave up on that rather quickly. | ||
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| + | ==== How much water does the laboratory use? ==== | ||
| + | //(from Brad Bull)// Our estimated annual usage is about 36M gallons. Peak is 250k a day during the hottest time of year. Most of the water is used for evaporative cooling (cooling towers). | ||
| + | |||
| + | ==== What will happen to the cyclotrons when they are removed to make way for the FRIB linac? ==== | ||
| + | //(from Brad Sherrill)// | ||
| + | They might be repurposed for other research at MSU. There are no plans to send them anywhere. | ||
| ==== Can I get a tour of the FRIB tunnel? ==== | ==== Can I get a tour of the FRIB tunnel? ==== | ||
| - | //(from Jessica Kolp)// Each Wednesday at 3:30-5:00, there is a public tour at FRIB Trailer #6. For the safety of our visitors, the following rules apply for FRIB construction site tours: | + | //(from Jessica Kolp and Rebecca Abel)// By appointment, after 3:30pm, groups may schedule a public tour starting at FRIB Trailer #6. For the safety of our visitors, the following rules apply for FRIB construction site tours: |
| * Closed-toe shoes or work boots required (no high heels, athletic/tennis shoes or sandals) | * Closed-toe shoes or work boots required (no high heels, athletic/tennis shoes or sandals) | ||
| * Long pants required (no shorts, capris, or dresses) | * Long pants required (no shorts, capris, or dresses) | ||
| * Must be more than 16 years old | * Must be more than 16 years old | ||
| * Safety gear will be provided | * Safety gear will be provided | ||
| + | |||
| + | ==== Fun FRIB facts ==== | ||
| + | //(from Brad Bull's Staff Info talk 6/24/17)// | ||
| + | * Concrete: ~35000 cubic yards | ||
| + | * Steel: >10 million lbs | ||
| + | * Soil excavated: ~150,000 cubic yards | ||
| + | * that soil would make a mountain 175 feet high | ||
| + | * Much off-side fabrication (two sites in Lansing) sped up work | ||
| + | * Power consumption: 18 MW | ||
| + | * Final square footage: 580,000 (double what NSCL was before) | ||
| + | * Planning, design, and construction are only 10-20% of total cost of ownership! | ||
| + | |||
| + | ==== What is the heaviest rare isotope beam ever studied at NSCL? ==== | ||
| + | Tellurium-134. | ||
| + | |||
| + | ==== What kind of controls are used? ==== | ||
| + | //(From the NSCL website)// EPICS - Experimental Physics and Industrial Control System is a distributed control system that was written jointly by LosAlamos an Argonne National Laboratories. It is also the control system used to control and monitor the NSCL Control system and beamlines. The NSCL data acquisition system has a certain level of support for accessing EPICS. This support gets built if the EPICS base software can be located at configuration time when the NSCL DAQ software is built and installed. Please note that the NSCL data acquisition group has also written a more complete EPICS access package, with Tcl/Tk EPICS aware widgets that is distributed seperately. That software is tested on Linux, Windows as well as MAC OS-X. | ||
| ==== How much did all this cost? ==== | ==== How much did all this cost? ==== | ||
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| ==== What exciting discoveries have been made HERE at NSCL? ==== | ==== What exciting discoveries have been made HERE at NSCL? ==== | ||
| - | According to RISAC report on 12/8/06: "Shell structure of exotic nuclei with knockout reactions", "Shell structure changes in exotic nuclei", and "78-Ni lifetime". We did pioneer the use of a superconducting cyclotron, including one for neutron therapy at Harper Hospital. We are also doing important work in the field of astrophysics, helping to explain observed astronomical phenomena by studying the nuclear processes involved. Research here is helping explain the r-process (formation of heavy elements in supernovae) and the nature of nuclear processes/explosions on neutron stars. In early 2007, we discovered the heaviest known isotope of silicon. NSCL is also the birthplace for many new technologies (such as superconducting cyclotrons, next-generation ion sources, and radiation-resistant magnets) that are spun off into other applications. | + | According to RISAC report on 12/8/06: "Shell structure of exotic nuclei with knockout reactions", "Shell structure changes in exotic nuclei", and "78-Ni lifetime". We did pioneer the use of a superconducting cyclotron, including one for neutron therapy at Harper Hospital. We are also doing important work in the field of astrophysics, helping to explain observed astronomical phenomena by studying the nuclear processes involved. Research here is helping explain the r-process (formation of heavy elements in supernovae) and the nature of nuclear processes/explosions on neutron stars. In early 2007, we discovered the heaviest known isotope of silicon. In 2012, we observed [[https://people.nscl.msu.edu/~brown/brown-all-papers/481-2012-PhysRevLett.108.102501.pdf|dineutron decay]] for the first time. In 2016, we discovered the first instance of a [[http://www.nscl.msu.edu/news/news-23.html|"bubble nucleus" in silicon-34]]. NSCL is also the birthplace for many new technologies (such as superconducting cyclotrons, next-generation ion sources, and radiation-resistant magnets) that are spun off into other applications. |
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| //(from Dallas Cole)// Many of our beams are created using monoisotopic elements or elements that are naturally very high in isotopic | //(from Dallas Cole)// Many of our beams are created using monoisotopic elements or elements that are naturally very high in isotopic | ||
| abundance of the isotope we require, such as 238Uranium or 40Calcium. For these beams we purchase materials from common domestic chemical suppliers, such as Alfa Aesar in Massachusetts. Most of our enriched isotopes used to produce beams, such as 48Calcium or 78Krypton come from Russia through either US or Canadian distributors. The US has an inventory of these isotopes at Oak Ridge, but does not actively produce them anymore. The competitive commercial culture in Russia makes them substantially more economical in supplying our needs. | abundance of the isotope we require, such as 238Uranium or 40Calcium. For these beams we purchase materials from common domestic chemical suppliers, such as Alfa Aesar in Massachusetts. Most of our enriched isotopes used to produce beams, such as 48Calcium or 78Krypton come from Russia through either US or Canadian distributors. The US has an inventory of these isotopes at Oak Ridge, but does not actively produce them anymore. The competitive commercial culture in Russia makes them substantially more economical in supplying our needs. | ||
| - | //(from Andreas Stolz)// Up to Calcium (Z=20) beams are produced with all electrons stripped off (totally ionized) in the K1200. The heaviest beam of those would be Ca-48. | + | //(from Andreas Stolz)// Up to Calcium (Z=20) beams are produced with all electrons stripped off (totally ionized) in the K1200. The heaviest beam of those would be Ca-48. //(from David Poe's cyclotron training slides)// K1200 stripper foil is of thin carbon, and the final charge state in k1200 = 2.3-2.7 times that in k500. There are 31 foils in the stripper, on a bicycle chain. |
| ==== Why do the cyclotrons have three "dees"? ==== | ==== Why do the cyclotrons have three "dees"? ==== | ||
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| ==== What are the advantages of a cyclotron over a linear accelerator? ==== | ==== What are the advantages of a cyclotron over a linear accelerator? ==== | ||
| - | See the wiki about cyclotrons: [[http://en.wikipedia.org/wiki/Cyclotron#Advantages_of_the_Cyclotron|Advantages/Limitations of Cyclotrons]]. To summarize, the three pole tips in our cyclotrons can be used to accelerate the same nuclei again and again. This translates to a major savings in cost and space. Also, the design of the K1200/K500 compensates for relativistic effects, so they can accelerate nuclei up to a significant fraction of the speed of light (the other wiki asserts a limitation of about 1% light speed). //(from David Poe's cyclotron training slides)// Four magnet coils create increasing field with radius to account for relativistic mass increase (B=Bo*gamma). | + | See the wiki about cyclotrons: [[http://en.wikipedia.org/wiki/Cyclotron#Advantages_of_the_Cyclotron|Advantages/Limitations of Cyclotrons]]. To summarize, the three pole tips in our cyclotrons can be used to accelerate the same nuclei again and again. This translates to a major savings in cost and space. Also, the design of the K1200/K500 compensates for relativistic effects, so they can accelerate nuclei up to a significant fraction of the speed of light (the other wiki asserts a limitation of about 1% light speed). The cyclotrons are isochronous, meaning that their magnetic fields increase with radius. //(from David Poe's cyclotron training slides)// Four magnet coils create increasing field with radius to account for relativistic mass increase (B=Bo*gamma). This actually focuses the beam in radius but defocuses it in the vertical dimension. |
| ==== Then what are the advantages of linear accelerators, such as FRIB? ==== | ==== Then what are the advantages of linear accelerators, such as FRIB? ==== | ||
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| * 2013: ReA3 reaccelerator commissioned. | * 2013: ReA3 reaccelerator commissioned. | ||
| * 2015: ReA3 experiments begin. | * 2015: ReA3 experiments begin. | ||
| - | * 2016: Cyclotron Gas Stopper online? | + | * 2019: Cyclotron Gas Stopper online? |
| * 2022: FRIB comes online? | * 2022: FRIB comes online? | ||
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| ==== How many nuclei are in the beam? ==== | ==== How many nuclei are in the beam? ==== | ||
| - | Beam density is measured in current... that's a good description for a beam of moving positively-charged ions. Our ECR can produce varying amounts of ions, depending on the desired element. One example is a "primary beam" from the source of oxygen-16. The ECR can reliably produce 100 pnA (particle nano-amps) of this element, which equates to between 10 and 100 billion particles per second (a beam power of about 1.3 kW). Once the CCF has fragmented the primary beam and produced a filtered rare isotope beam, it represents a tiny fraction of the initial current. Beams made of isotopes near stability will contain millions of particles per second, while extremely unstable/rare isotopes could be produced at the rate of one per hour or even less! | + | Beam density is measured in current... that's a good description for a beam of moving positively-charged ions. Our ECR can produce varying amounts of ions, depending on the desired element. One example is a "primary beam" from the source of oxygen-16. The ECR can reliably produce 100 pnA (particle nano-amps) of this element, which equates to between 10 and 100 billion particles per second (a beam power of about 0.2 kW). Once the CCF has fragmented the primary beam and produced a filtered rare isotope beam, it represents a tiny fraction of the initial current. Beams made of isotopes near stability will contain millions of particles per second, while extremely unstable/rare isotopes could be produced at the rate of one per hour or even less! |
| ==== How long does it take for a nucleus to get from the ion source to a detector? ==== | ==== How long does it take for a nucleus to get from the ion source to a detector? ==== | ||
tours/faq.txt · Last modified: 2024/05/30 09:23 by constan
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