scholarly journals Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

2015 ◽  
Vol 86 (8) ◽  
pp. 084102 ◽  
Author(s):  
Yunteng He ◽  
Jie Zhang ◽  
Yang Li ◽  
William M. Freund ◽  
Wei Kong
Keyword(s):  
Superfluid Helium ◽  
Time Of Flight ◽  
Helium Droplet

scholarly journals Helium droplet infrared spectroscopy of glycine and glycine–water aggregates

2016 ◽  
Vol 18 (40) ◽  
pp. 28082-28090 ◽  
Author(s):  
Matin Kaufmann ◽  
Daniel Leicht ◽  
Raffael Schwan ◽  
Devendra Mani ◽  
Gerhard Schwaab ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Superfluid Helium ◽  
Frequency Range ◽  
Helium Nanodroplets ◽  
Helium Droplet ◽  
Infrared Absorption Spectra

Infrared absorption spectra of glycine and glycine–water aggregates embedded in superfluid helium nanodroplets were recorded in the frequency range 1000–1450 cm−1.

scholarly journals Nano-scale energetic films by superfluid helium droplet assembly

2014 ◽  
Vol 500 (5) ◽  
pp. 052012 ◽  
Author(s):  
S B Emery ◽  
J M Boyle ◽  
K B Rider ◽  
B K Little ◽  
C M Lindsay
Keyword(s):  
Superfluid Helium ◽  
Nano Scale ◽  
Helium Droplet

scholarly journals London Dispersion Dominating Diamantane Packing in Helium Nanodroplets

2021 ◽  
Author(s):  
Jasna Alić ◽  
Roman Messner ◽  
Florian Lackner ◽  
Wolfgang E Ernst ◽  
Marina Šekutor
Keyword(s):  
Mass Spectrometry ◽  
Superfluid Helium ◽  
Time Of Flight ◽  
Magic Numbers ◽  
Helium Nanodroplets ◽  
Flight Mass Spectrometry ◽  
Distinct Cluster ◽  
London Dispersion

Diamantane clusters formed inside superfluid helium nanodroplets were analyzed by time-of-flight mass spectrometry. Distinct cluster sizes were identified as “magic numbers” and the corresponding feasible structures for clusters consisting of...

Bimodal velocity and size distributions of pulsed superfluid helium droplet beams

2021 ◽  
Vol 154 (13) ◽  
pp. 134303
Author(s):  
Rahul Pandey ◽  
Steven Tran ◽  
Jie Zhang ◽  
Yuzhong Yao ◽  
Wei Kong
Keyword(s):  
Superfluid Helium ◽  
Size Distributions ◽  
Helium Droplet

Applications of Time-OF-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

1990 ◽  
Vol 48 (2) ◽  
pp. 308-309
Author(s):  
Bruno Schueler ◽  
Robert W. Odom
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Structural Information ◽  
Time Of Flight ◽  
Biological Tissues ◽  
Polymer Surfaces ◽  
Tof Sims ◽  
Secondary Ions ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides unique capabilities for elemental and molecular compositional analysis of a wide variety of surfaces. This relatively new technique is finding increasing applications in analyses concerned with determining the chemical composition of various polymer surfaces, identifying the composition of organic and inorganic residues on surfaces and the localization of molecular or structurally significant secondary ions signals from biological tissues. TOF-SIMS analyses are typically performed under low primary ion dose (static SIMS) conditions and hence the secondary ions formed often contain significant structural information.This paper will present an overview of current TOF-SIMS instrumentation with particular emphasis on the stigmatic imaging ion microscope developed in the authors’ laboratory. This discussion will be followed by a presentation of several useful applications of the technique for the characterization of polymer surfaces and biological tissues specimens. Particular attention in these applications will focus on how the analytical problem impacts the performance requirements of the mass spectrometer and vice-versa.

High-Resolution Cryo-Electron Microscopy of Biological Macromolecules

1990 ◽  
Vol 48 (1) ◽  
pp. 126-127
Author(s):  
Yoshinori Fujiyoshi
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Diffraction Pattern ◽  
Superfluid Helium ◽  
Copper Phthalocyanine ◽  
Optical Diffraction ◽  
Irradiation Damage ◽  
Biological Macromolecules ◽  
Cross Sectional ◽  
Instrumental Resolution

The resolution of direct images of biological macromolecules is normally restricted to far less than 0.3 nm. This is not due instrumental resolution, but irradiation damage. The damage to biological macromolecules may expect to be reduced when they are cooled to a very low temperature. We started to develop a new cryo-stage for a high resolution electron microscopy in 1983, and successfully constructed a superfluid helium stage for a 400 kV microscope by 1986, whereby chlorinated copper-phthalocyanine could be photographed to a resolution of 0.26 nm at a stage temperature of 1.5 K. We are continuing to develop the cryo-microscope and have developed a cryo-microscope equipped with a superfluid helium stage and new cryo-transfer device.The New cryo-microscope achieves not only improved resolution but also increased operational ease. The construction of the new super-fluid helium stage is shown in Fig. 1, where the cross sectional structure is shown parallel to an electron beam path. The capacities of LN2 tank, LHe tank and the pot are 1400 ml, 1200 ml and 3 ml, respectively. Their surfaces are placed with gold to minimize thermal radiation. Consumption rates of liquid nitrogen and liquid helium are 170 ml/hour and 140 ml/hour, respectively. The working time of this stage is more than 7 hours starting from full LN2 and LHe tanks. Instrumental resolution of our cryo-stage cooled to 4.2 K was confirmed to be 0.20 nm by an optical diffraction pattern from the image of a chlorinated copper-phthalocyanine crystal. The image and the optical diffraction pattern are shown in Fig. 2 a, b, respectively.

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