Production of HD Molecules in Definite Hyperfine Substates

Engels, R.; Grigoryev, K.; Kannis, C. S.; Michael, Y.; Ströher, H.; Verhoeven, V.W.J.; Büscher, M.; Huxold, L.; Kochenda, L.; Кравцов, П.; Trofimov, V.; Vasilyev, A.; Взнуздаев, М.

doi:10.1103/physrevlett.124.113003

Cited by 7 publications

(8 citation statements)

References 21 publications

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“…Powering the magnet at its maximum allowed current (180 A), we measured 1.2 T in the middle of the poles. The required magnetic field for fusion application is in the range of 1 T, which matches exactly with the system used to produce hyper-polarized molecules as fusion fuel from the recombination of a polarized atomic beam [6].…”

Section: Materials and Equipmentmentioning

confidence: 80%

“…We exploited the opportunity to upgrade our system to host a new coldhead (RDK-415D from SHI Cryogenics Group), available from our collaborators [6], with a nominal temperature of 40 K and a cooling power in the range of 42 W on the first stage and 4 K and 1.8 W on the second stage.…”

Section: Details On Solutions Adopted In the Upgraded Systemmentioning

confidence: 99%

“…Magnetic fields are required to maintain the polarization of polarized nuclear substances in various activities and during transportation. Specifically, the main purpose of this contribution is to provide holding fields for polarized fuel in fusion tests [6]. Ideas and support on this topic come from studies and developments on spin-dependent studies in nuclear and subnuclear physics [7] in which nuclear-polarized targets are used.…”

Section: Introductionmentioning

confidence: 99%

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Bulk superconducting materials as a tool for control, confinement, and accumulation of polarized substances: the case of MgB2

Ciullo,

Barion,

Contalbrigo

et al. 2024

Front. Phys.

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Providing strong magnetic holding fields while at the same time guaranteeing shielding from unwanted external fields is a key requirement for the accumulation, preservation, and transport of nuclear-polarized materials: it is a crucial achievement for its exploitation in fusion test facilities and particle physics. High-temperature bulk superconducting materials represent an innovative and promising solution, as they are easily machinable and can be cooled by a coldhead. This work considers a bulk MgB2 superconducting hollow cylinder, and the successful preliminary studies, performed by measuring trapped fields in the order of 1 T in its center, encouraged us to upgrade the prototype apparatus for deep insight and knowledge. The new system allows working at a lower temperature of 8 K, exchanging cylinders and returning to working conditions in 1 day, and mapping the transverse fields along the radial coordinate (in 11 mm) and along the symmetry axis (in 48 mm). Then, it allows us to find the proper geometry and the production procedure for its use in a fusion test facility. The commissioning of the upgraded system provides results already useful for polarized fusion fuel, for instance, as a holding field for recombined hyper-polarized molecules from the recombination of atomic polarized beams, and it also gives the possibility of investigating the use of MgB2 in polarized nuclear targets.

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Section: Materials and Equipmentmentioning

confidence: 80%

Section: Details On Solutions Adopted In the Upgraded Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bulk superconducting materials as a tool for control, confinement, and accumulation of polarized substances: the case of MgB2

Ciullo,

Barion,

Contalbrigo

et al. 2024

Front. Phys.

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“…This would require less of a construction project, mainly adapting existing equipment, but would involve many more stages and would become more of a labor effort. (There are also Stern-Gerlach based molecular-beam methods of producing polarized D 2 that could in principle be utilized [70,71], at least for a polarization survival test. However, since their fluxes are rather low, material would have to be collected over some time period without losing significant polarization, and a method would need to be developed to encapsulate the resulting polarized D 2 for injection.…”

Section: Polarized D Pellet Fuelingmentioning

confidence: 99%

Polarized fusion and potential in situ tests of fuel polarization survival in a tokamak plasma

et al. 2023

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The use of spin-polarized fusion fuels would provide a significant boost towards the ignition of a burning plasma. The cross section for D+T→ α+n, would be increased by 1.5 if the fuels were injected with parallel polarization. Furthermore, our simulations demonstrate additional non-linear power gains in large-scale machines such as ITER, due to increased alpha heating. Such benefits require the survival of spin polarizations for periods comparable to the particle confinement time. During the 1980s, calculations predicted that polarizations could survive a plasma environment, although concerns persisted regarding the cumulative impacts of wall recycling. In that era, technical challenges prevented direct tests and left the large scale fueling of a power reactor beyond reach. Over the last decades, this situation has dramatically changed. Detailed simulations of ITER have predicted negligible wall recycling in a high-power reactor, and recent advances in laser-driven sources project the capability of producing large quantities of ~100% polarized D and T. The remaining crucial step is an in-situ demonstration of polarization survival in a plasma. For this, we outline a measurement strategy using the isospin-mirror reaction, D+3He→ α+p. Polarized 3He avoids the complexities of handling tritium, while encompassing the same spin-physics. We evaluate two methods of delivering deuterium, using dynamically polarized Lithium-Deuteride (with vector polarization PV D of 70%) or frozen-spin Hydrogen-Deuteride (with PV D of 40%), together with a method of injecting optically-pumped 3He (with 65% polarization). Pellets of these materials all have long polarization decay times (~6 minutes for LiD at 2K, ~2 months for HD at 2K, and ~3 days for 3He at 77K), all far greater than a plasma shot in a research tokamak such as DIII-D. Both species can be propelled from a single cryogenic injection gun. We review plasma requirements and strategies for detecting polarization survival. Polarization alters both fusion yields and the angular distribution of fusion products, and each of these provides a potential signal. In this paper we simulate a selection of shots with similar characteristics in a future high-Tion H plasma, and find ratios of yields from shots with fuel spins parallel and antiparallel reaching 1.3 (HD+3He) to 1.6 (LiD+3He) over a wide range of poloidal angles. (A companion paper finds sensitivity to fusion product angular distributions as reflected in the pitch angles of protons and alphas reaching the plasma facing wall.)

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“…In past experiments polarization measurements with a Lamb-shift Polarimeter (LSP) were typically performed with protons or deuterons. In more recent projects it was shown that the polarization measurement of 𝐻 + 2 , 𝐷 + 2 and 𝐻𝐷 + molecular ions is possible as well [1,2]. Furthermore, there exists a debate about the possibility to measure the polarization of 𝐻 − ions directly with a LSP.…”

Section: Introductionmentioning

confidence: 99%

Polarization measurement of a pulsed 𝑯− / 𝑫− ion Beam with a Lamb-shift Polarimeter

Pütz¹,

Engels²,

Gebel³

et al. 2023

Proceedings of 19th Workshop on Polarized Sources, Targets and Polarimetry — PoS(PSTP2022)

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At the FZ Jülich a polarized ion source produces a pulsed beam of nuclear spin polarized 𝐻 − or 𝐷 − ions for stripping injection into the storage ring COSY. Before injection, the nuclear polarization needs to be determined and optimized. Until now, this is done with a device called Low Energy Polarimeter (LEP), which is based on the polarization dependent elastic scattering of protons on a carbon foil. This procedure requires a pre-accelerated beam of 45 MeV from the cyclotron JULIC and is also time consuming. To make this measurement faster and more energy efficient (cheaper), the idea was to measure the polarization directly behind the source with a Lamb-shift Polarimeter (LSP). Typically, LSP measurements are performed with protons but in this experiment it was shown that a polarization measurement is possible by using 𝐻 − or 𝐷 − ions directly. First results of the polarization measurements for this pulsed negative ion beam are presented as well as further ideas, e.g. for the automatization of the process, are discussed.

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Production of HD Molecules in Definite Hyperfine Substates

Cited by 7 publications

References 21 publications

Bulk superconducting materials as a tool for control, confinement, and accumulation of polarized substances: the case of MgB2

Bulk superconducting materials as a tool for control, confinement, and accumulation of polarized substances: the case of MgB2

Polarized fusion and potential in situ tests of fuel polarization survival in a tokamak plasma

Polarization measurement of a pulsed 𝑯− / 𝑫− ion Beam with a Lamb-shift Polarimeter

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