Development of a polarized target for nuclear fusion experiments

Iio, M.; Daito, I.; Doshita, N.; Hasegawa, T.; Horikawa, N.; Inagaki, Takefumi; Ishii, Satoshi; Iwata, T.; Kobayashi, T.; Kondo, K.; Matsuda, T.; Okumura, N.; Shinba, T.; Tagishi, Y.; Tajima, Y.; Yamaguchi, Mitsutaka; Yoshimaru, N.

doi:10.1016/j.nima.2004.03.174

Cited by 10 publications

(6 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Deuteron polarization values of about 10% [5] have been measured at 2.5 T and 0.8 K. TEMPO radicals, introduced into the target foils by a heating procedure , have been used as paramagnetic centers [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

DNP measurements of irradiated deuterated polyethylene

Wang¹

2016

Proceedings of XVIth International Workshop in Polarized Sources, Targets, and Polarimetry — PoS(PSTP2015)

View full text Add to dashboard Cite

Deuterated polyethylene samples have been prepared as polarizable target material. The paramagnetic centers necessary for the dynamic nuclear polarization process have been created by irradiation with electrons. The paramagnetic resonance from the induced centers into the samples has been studied in a conventional X-band EPR spectrometer operating at 9.35 GHz and at liquid nitrogen temperature. In a fully deuterated polyethylene sample more than 30% deuteron polarization has been achieved at dilution refrigerator temperature and 2.5 T.

show abstract

Section: Introductionmentioning

confidence: 99%

“…(b) Chemically doped polyethylene: TEMPO doped foil with deuteron polarization of 10% [5]. (c) Chemically doped polystyrene: In a Finland D36 doped deuterated polystyrene foil sample 61.5 % deuteron polarization has been obtained in a dilution refrigerator at 5.0 T [9].…”

Section: Introductionmentioning

confidence: 99%

DNP measurements of irradiated deuterated polyethylene

Wang¹

2016

Proceedings of XVIth International Workshop in Polarized Sources, Targets, and Polarimetry — PoS(PSTP2015)

View full text Add to dashboard Cite

show abstract

“…A TEMPO doped deuterated polyethylene (CD 2 ) foil target prepared by the diffusion method has been installed for a 20 MeV fusion experiment [7].…”

Section: Introductionmentioning

confidence: 99%

DNP with Trityl Radicals in Deuterated Polyethylene

Wang

Meyer

Берлин

et al. 2016

Int. J. Mod. Phys. Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…These experiments achieve nuclear spin polarization by magnetically separating the nuclear spin states via the Stern-Gerlach effect in molecular beams, a process however which limits the achievable production rates to ∼ 10 16 atoms s −1 [2], and the projected D-D fusion reaction rate to as low as ∼0.01 neutrons s −1 [12]. Polarized solid deuterium targets can be produced where the densities can reach as high as 2.5 × 10 19 spins/cm 3 , albeit in much lower polarization close to 10% [13]. Another approach for the production of polarized sold fuel involves accumulating the hyperpolarized deuterium in specially coated storage cells [11].…”

mentioning

confidence: 99%

“…19 spins/cm 3 , albeit in much lower polarization close to 10% [13]. Another approach for the production of polarized sold fuel involves accumulating the hyperpolarized deuterium in specially coated storage cells [11].…”

mentioning

confidence: 99%

Highly Nuclear-Spin-Polarized Deuterium Atoms from the UV Photodissociation of Deuterium Iodide

et al. 2017

View full text Add to dashboard Cite

We report the production of highly spin-polarized Deuterium atoms via photodissociation of deuterium iodide at 270 nm. The velocity distribution of both the deuterium and iodine photodissociation products is performed via velocity mapping slice-imaging. Additionally, the angular momentum polarization of the iodine products is studied using polarization-sensitive ionization schemes. The results are consistent with excitation of the A 1 Π1 state followed by adiabatic dissociation. The process produces ∼100% electronically polarized deuterium atoms at the time of dissociation, which is then converted to ∼ 60% nuclear D polarization after ∼ 1.6 ns. These production times for hyperpolarized deuterium allow collision-limited densities of ∼ 10 18 cm −3 , which is ∼ 10 6 times higher than conventional (Stern-Gerlach separation) methods. We discuss how such high-density hyperpolarized deuterium atoms can be combined with laser fusion to measure polarized D-D fusion cross sections.PACS numbers: 33.80. Gj, 32.10.Fn Controlling the nuclear spin polarization in fusion reactions offers important advantages, such as larger reaction cross sections, control over the emission direction of products, and in some cases eliminating hazardous neutron emission [1,2]. In the case of the five-nucleon reactions D + T → n + 4 He and D + 3 He → p + 4 He, it is well known that the reaction cross section increases by ∼50% when the fused nuclei have oriented nuclear spins [3,4].For the 4-nucleon D+D reaction, over the important energy range of 10-100 keV, the situation is unclear, since several predictions range from enhancement of the reaction, suppression of the reaction, or almost no effect at all [5][6][7][8][9][10]. The technical challenges of measuring fusion polarization dynamics limits the number of experiments which pursue this direction to two facility-scale experiments [11]. These experiments achieve nuclear spin polarization by magnetically separating the nuclear spin states via the Stern-Gerlach effect in molecular beams, a process however which limits the achievable production rates to ∼ 10 16 atoms s −1 [2], and the projected D-D fusion reaction rate to as low as ∼0.01 neutrons s −1 [12]. Polarized solid deuterium targets can be produced where the densities can reach as high as 2.5 × 10 19 spins/cm 3 , albeit in much lower polarization close to 10% [13]. Another approach for the production of polarized sold fuel involves accumulating the hyperpolarized deuterium in specially coated storage cells [11].Laser photodissociation of hydrogen halides has been shown to produce highly polarized H atoms [14][15][16][17]. The photodissociation process initially polarizes the electron spin up to 100% (for photofragment velocities parallel to the propagation direction of the circularly-polarized dissociation laser) [18]; due to the hyperfine interaction, the polarization oscillates back and forth between the electronic and the nuclear spin on the ∼1-ns timescale. By terminating this polarization exchange appropriately, for example by ioni...

show abstract

Development of a polarized target for nuclear fusion experiments

Cited by 10 publications

References 11 publications

DNP measurements of irradiated deuterated polyethylene

DNP measurements of irradiated deuterated polyethylene

DNP with Trityl Radicals in Deuterated Polyethylene

Highly Nuclear-Spin-Polarized Deuterium Atoms from the UV Photodissociation of Deuterium Iodide

Contact Info

Product

Resources

About