A Large Mass Spectrometer Employing Crossed Electric and Magnetic Fields

Mariner, Thomas; Bleakney, Walker

doi:10.1063/1.1741511

Cited by 20 publications

(9 citation statements)

References 14 publications

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“…Inside the magnet vacuum chamber, top-and bottom-striped circuit boards with resistor chains created a uniform electric field perpendicular to both the magnetic field and the velocity vector of the entering ions. By suitable choice of the crossed magnetic and electric field strengths, the ions follow trochoidal trajectories [23][24][25][26][27]. The period and beam-direction precession of these trochoids depends on the A/q and is independent of velocity.…”

Section: Measurement Periods Alternated Between MC Production (8 H) Amentioning

confidence: 99%

First Direct Measurements of Superheavy-Element Mass Numbers

et al. 2018

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An experiment was performed at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron to determine the mass number of a superheavy element. The measurement resulted in the observation of two α-decay chains, produced via the 243 Am(48 Ca,xn) 291-x Mc reaction, that were separated by mass-tocharge ratio (A/q) and identified by the combined BGS+FIONA apparatus. One event occurred at A/q=284 and was assigned to 284 Nh (Z=113), the α-decay daughter of 288 Mc (Z=115), while the second occurred at A/q=288 and was assigned to 288 Mc. This experiment represents the first direct measurements of the mass numbers of superheavy elements, confirming previous (indirect) massnumber assignments. Atoms of superheavy elements (SHE) have been produced at the Joint Institute for Nuclear Research (JINR) in compound-nucleus reactions between 48 Ca projectiles and actinide targets (hot fusion reactions) for nearly 20 years [1-3]. During the last several years, SHE production in such hot fusion reactions has been reported from laboratories in the USA [4-6], Germany [7-11], and Japan [12], both

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Section: Measurement Periods Alternated Between MC Production (8 H) Amentioning

confidence: 99%

First Direct Measurements of Superheavy-Element Mass Numbers

et al. 2018

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“…1, label 11) [6]. The spectrometer utilizes crossed magnetic and electric fields, tuned to force the ions traveling through the spectrometer to take trochoidal trajectories [14][15][16][17]. These trajectories are heavily dependent on a particular ion's A=q and are largely independent of its velocity.…”

mentioning

confidence: 99%

Identification of the New Isotope Md244

et al. 2020

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In an experiment performed at Lawrence Berkeley National Laboratory's 88-inch cyclotron, the isotope 244 Md was produced in the 209 Bið 40 Ar; 5nÞ reaction. Decay properties of 244 Md were measured at the focal plane of the Berkeley Gas-filled Separator, and the mass number assignment of A ¼ 244 was confirmed with the apparatus for the identification of nuclide A. The isotope 244 Md is reported to have one, possibly two, α-decaying states with α energies of 8.66(2) and 8.31(2) MeV and half-lives of 0.4 þ0.4 −0.1 and ∼6 s, respectively. Additionally, first evidence of the α decay of 236 Bk was observed and is reported.

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“…FIONA separates ions by their A / q with the use of a trochoidal spectrometer . The trochoidal spectrometer consists of crossed magnetic and electric fields, which force ions to follow trochoidal trajectories through a spectrometer. − The period and beam direction precession of these trochoids is dependent on the A / q of a given ion and is largely independent of the ion velocity.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…FIONA separates ions by their A/q with the use of a trochoidal spectrometer [37]. The trochoidal spectrometer consists of crossed magnetic and electric fields, which force ions to follow trochoidal trajectories through the spectrometer [38][39][40][41].…”

Section: Isotope Separation With the Bgs And Fionamentioning

confidence: 99%

Assessment of the Second-Ionization Potential of Lawrencium: Investigating the End of the Actinide Series with a One-Atom-at-a-Time Gas-Phase Ion Chemistry Technique

et al. 2021

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Experiments were performed at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron facility to investigate the electron-transfer reduction reaction of dipositive Lr (Z = 103) with O 2 gas. Ions of 255 Lr were produced in the fusion−evaporation reaction 209 Bi( 48 Ca,2n) 255 Lr and were studied with a novel gas-phase ion chemistry technique. The produced 255 Lr 2+ ions were trapped and O 2 gas was introduced, such that the charge-exchange reaction to reduce 255 Lr 2+ to 255 Lr 1+ was observed and the reaction rate constant was determined to be k = 1.5(7) × 10 −10 cm 3 /mol/s. The observation that this reaction proceeds establishes the lower limit on the second ionization potential of Lr to be 13.3(3) eV. This gives further support that the actinide series terminates with Lr. Additionally, this result can be used to better interpret the situation concerning the placement of Lu and Lr on the periodic table within the current framework of the actinide hypothesis. The success of this experimental approach now identifies unique opportunities for future gas-phase reaction studies on actinide and super heavy elements.

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A Large Mass Spectrometer Employing Crossed Electric and Magnetic Fields

Cited by 20 publications

References 14 publications

First Direct Measurements of Superheavy-Element Mass Numbers

First Direct Measurements of Superheavy-Element Mass Numbers

Identification of the New Isotope Md244

Assessment of the Second-Ionization Potential of Lawrencium: Investigating the End of the Actinide Series with a One-Atom-at-a-Time Gas-Phase Ion Chemistry Technique

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