dorsal/arxiv
View SchemaThe cyclotron gas stopper project at the NSCL
| Authors | C. Guenaut, G. Bollen, S. Chouhan, F. Marti, D. J. Morrissey, D. Lawton, J. Ottarson, G. K. Pang, S. Schwarz, B. M. Sherrill, M. Wada, A. F. Zeller |
|---|---|
| Categories | |
| ArXiv ID | physics/0703232 |
| URL | https://arxiv.org/abs/physics/0703232 |
| DOI | 10.1007/s10751-007-9539-y |
Abstract
Gas stopping is becoming the method of choice for converting beams of rare isotopes obtained via projectile fragmentation and in-flight separation into low-energy beams. These beams allow ISOL-type experiments, such as mass measurements with traps or laser spectroscopy, to be performed with projectile fragmentation products. Current gas stopper systems for high-energy beams are based on linear gas cells filled with 0.1-1 bar of helium. While already used successfully for experiments, it was found that space charge effects induced by the ionization of the helium atoms during the stopping process pose a limit on the maximum beam rate that can be used. Furthermore, the extraction time of stopped ions from these devices can exceed 100 ms causing substantial decay losses for very short-lived isotopes. To avoid these limitations, a new type of gas stopper is being developed at the NSCL/MSU. The new system is based on a cyclotron-type magnet with a stopping chamber filled with Helium buffer gas at low pressure. RF-guiding techniques are used to extract the ions. The space charge effects are considerably reduced by the large volume and due to a separation between the stopping region and the region of highest ionization. Cyclotron gas stopper systems of different sizes and with different magnetic field strengths and field shapes are presently investigated.
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"abstract": "Gas stopping is becoming the method of choice for converting beams of rare\nisotopes obtained via projectile fragmentation and in-flight separation into\nlow-energy beams. These beams allow ISOL-type experiments, such as mass\nmeasurements with traps or laser spectroscopy, to be performed with projectile\nfragmentation products. Current gas stopper systems for high-energy beams are\nbased on linear gas cells filled with 0.1-1 bar of helium. While already used\nsuccessfully for experiments, it was found that space charge effects induced by\nthe ionization of the helium atoms during the stopping process pose a limit on\nthe maximum beam rate that can be used. Furthermore, the extraction time of\nstopped ions from these devices can exceed 100 ms causing substantial decay\nlosses for very short-lived isotopes. To avoid these limitations, a new type of\ngas stopper is being developed at the NSCL/MSU. The new system is based on a\ncyclotron-type magnet with a stopping chamber filled with Helium buffer gas at\nlow pressure. RF-guiding techniques are used to extract the ions. The space\ncharge effects are considerably reduced by the large volume and due to a\nseparation between the stopping region and the region of highest ionization.\nCyclotron gas stopper systems of different sizes and with different magnetic\nfield strengths and field shapes are presently investigated.",
"arxiv_id": "physics/0703232",
"authors": [
"C. Guenaut",
"G. Bollen",
"S. Chouhan",
"F. Marti",
"D. J. Morrissey",
"D. Lawton",
"J. Ottarson",
"G. K. Pang",
"S. Schwarz",
"B. M. Sherrill",
"M. Wada",
"A. F. Zeller"
],
"categories": [
"physics.ins-det"
],
"doi": "10.1007/s10751-007-9539-y",
"title": "The cyclotron gas stopper project at the NSCL",
"url": "https://arxiv.org/abs/physics/0703232"
},
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"variant": "snapshot-2026-03-01",
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