The Spallation Neutron Source Beam Commissioning and Initial Operations

Henderson, Stuart; Aleksandrov, A.; Allen, C.K.; Assadi, S.; Bartoski, Dirk; Blokland, W.; Casagrande, F.; Campisi, I.E.; Chu, C.; Cousineau, S.; Crofford, M.; Danilov, V.; Deibele, C.; Dodson, G.; Feshenko, A.; Galambos, J.; Han, Binghong; Hardek, T.; Holmes, Jeffrey; Holtkamp, N.; Howell, M.; Jeon, D.; Kang, Y.; Kasemir, Kay; Kim, Sang-ho; Kravchuk, L.; Long, Cary D.; McManamy, T.J.; Pelaia, T.; Piller, C.; Plum, Michael; Pogge, J.; Purcell, J.; Shea, Thomas; Shishlo, A.; Sibley, C.; Stöckli, M. P.; Stout, D.; Tanke, E.; Welton, R. F.; Zhang, Y.; Zhukov, Alexander

doi:10.2172/1242669

Cited by 3 publications

(3 citation statements)

References 30 publications

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“…This is because HAR, also a development in the QCr field, better-known than the XCW method, is capable of obtaining hydrogen atom positions and ADPs in agreement with independent neutron diffraction experiments in a 'fairly automatic and standard way' (Woin ´ska et al, 2016). HAR is particularly significant for molecular biology because hydrogen atoms play such a crucial role in that field, evidenced by the fact that billion-dollar spallation neutron sources have been commissioned in part to detect these atoms (Henderson et al, 2015;Hall-Wilton & Theroine, 2014). In this regard, it is worth mentioning that there have already been recent attempts to extend HAR for use in such macromolecular systems (Malaspina et al, 2019;Bergmann et al, 2020;Chodkiewicz et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

X-ray constrained wavefunctions based on Hirshfeld atoms. I. Method and review

Davidson¹,

Grabowsky²,

Jayatilaka³

2022

Acta Crystallogr B Struct Sci Cryst Eng Mater

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The X-ray constrained wavefunction (XCW) procedure for obtaining an experimentally reconstructed wavefunction from X-ray diffraction data is reviewed. The two-center probability distribution model used to perform nuclear-position averaging in the original paper [Grimwood & Jayatilaka (2001). Acta Cryst. A57, 87–100] is carefully distinguished from the newer one-center probability distribution model. In the one-center model, Hirshfeld atoms are used, and the Hirshfeld atom based X-ray constrained wavefunction (HA-XCW) procedure is described for the first time, as well as its efficient implementation. In this context, the definition of the related X-ray wavefunction refinement (XWR) method is refined. The key halting problem for the XCW method – the procedure by which one determines when overfitting has occurred – is named and work on it reviewed.

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Section: Introductionmentioning

confidence: 99%

X-ray constrained wavefunctions based on Hirshfeld atoms. I. Method and review

Davidson¹,

Grabowsky²,

Jayatilaka³

2022

Acta Crystallogr B Struct Sci Cryst Eng Mater

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“…But it is well known that spallation sources produce the highest neutron intensity among all types of neutron generation facilities. For example, for SNS [22] 1 GeV accelerated proton beam with a current of 1.5 mA interacts with a liquid mercury target. As a result, the neutron production intensity is 10 17 n/s.…”

Section: Neutron Activationmentioning

confidence: 99%

Charged and Neutral Particles Beams Application for Research of Accumulation Routes of the Medical Radioisotope 103pd

Hryhorenko

2023

Problems of Atomic Science and Technology

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The results of experimental data analysis about the accumulation routes of the important medical isotope 103Pd induced by charged particle beams (protons, deuterons, helium-3, helium-4) and neutral particles (gamma and neutrons) are presented. The main generalized data about the nuclear reaction cross-section of 103Pd production versus the irradiation techniques of natural and isotope-enriched targets and their content of unwanted accompanying radio nuclides were compared to theoretical predictions of too. The optimization procedure of the 103Pd accumulation is discussed in order to develop more promising ones, taking into account the requirements for the production of medical radioisotopes.

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“…The last two decades have seen significant advances in the construction and operation of a new generation of high-power particle accelerators, while new projects with more powerful beams are currently under consideration and construction [1][2][3][4][5][6][7][8][9][10][11][12]. However, the sustained and long-term operation of such machines is not without challenges: a key problem standing in the way of increased beam power is represented by beam losses associated with the expansion of phase space volume of the beam, and generation of a beam halo.…”

Section: Introductionmentioning

confidence: 99%

Six-dimensional matching of intense beam with linear accelerating structure

Batygin

2021

Nuclear Instruments and Methods in Physics Research Section A:

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Beam matching is a common technique that is routinely employed in accelerator design with the aim of minimizing beam losses and preservation of beam brightness. Despite being widely used, a full theoretical understanding of beam matching in 6D remains elusive. Here, we present an analytical treatment of 6D beam matching of a high-intensity beam onto an RF structure. We begin our analysis within the framework of a linear model, and apply the averaging method to a set of 3D beam envelope equations. Accordingly, we obtain a matched solution that is comprised of smoothed envelopes and periodic terms, describing envelope oscillations with the period of the focusing structure. We then consider the nonlinear regime, where the beam size is comparable with the separatrix size. Stating with a Hamiltonian analysis in 6D phase space, we attain a selfconsistent beam profile and show that it is significantly different from the commonly used ellipsoidal shape. Subsequently, we analyze the special case of an equilibrium with equal space charge depression between all degrees of freedom. Comparison of beam dynamics for equipartitioned, equal space charge depression, and equal emittances beams is given. Finally, we present experimental results on beam matching in the LANSCE linac.

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The Spallation Neutron Source Beam Commissioning and Initial Operations

Cited by 3 publications

References 30 publications

X-ray constrained wavefunctions based on Hirshfeld atoms. I. Method and review

X-ray constrained wavefunctions based on Hirshfeld atoms. I. Method and review

Charged and Neutral Particles Beams Application for Research of Accumulation Routes of the Medical Radioisotope 103pd

Six-dimensional matching of intense beam with linear accelerating structure

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