Investigating ion-surface collisions with a niobium superconducting tunnel junction detector in a time-of-flight mass spectrometer

Westmacott, Garrett; Fan, Zhengxiu; Frank, Matthias; Friedrich, S.; Labov, S. E.; Benner, W. Henry

doi:10.1002/(sici)1097-0231(20000415)14:7<600::aid-rcm915>3.0.co;2-0

Cited by 20 publications

(19 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…16 In brief, the STJ detector consists of three layers: a top 100-nm thick niobium layer, a 2-nm insulating aluminum oxide layer, and a base layer of niobium, 260-nm thick on a silicon substrate. The active area is 0.04 mm 2 .…”

Section: The Niobium Stj Detector Pulse-counting Setupmentioning

confidence: 99%

“…16 Thus, when two ions hit simultaneously, the detector pulse-height is about twice as large as the pulse produced by a single ion because two ions deposit twice the kinetic energy of a single ion. The signal from the STJ detector is used in two ways.…”

Section: The Niobium Stj Detector Pulse-counting Setupmentioning

confidence: 99%

“…The width of the CFD time pulses (1 V amplitude) were intentionally stretched to about 650 ns in order to provide a deadtime about equal to the deadtime of the STJ detector. 16 The various detector pulses are schematically represented in Fig. 1.…”

Section: The Masked-mcp Detector Pulse-counting Setupmentioning

confidence: 99%

“…Furthermore, STJ detectors have 100% efficiency for molecular ions with sufficient kinetic energy. The operating principle of the STJ detector, and the observation that there is no loss in sensitivity for detecting molecular ions with larger masses and sufficient total energy (b$5 keV), 16 allows us to assume that the STJ detector is 100% efficient for this experiment. See Westmacott et.…”

mentioning

confidence: 99%

“…al. 16 for more details about the operating principle of the STJ detector and its ion energy-measuring performance.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions

Westmacott¹,

Frank²,

Labov³

et al. 2000

Rapid Commun. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

An energy‐sensitive superconducting tunnel junction (STJ) detector was used to measure the secondary electron emission efficiency, ϵe, for a microchannel plate (MCP) detector bombarded by large (up to 66 kDa), slow moving (<40 km/s) molecular ions. The method used is new and provides a more direct procedure for measuring the efficiency of secondary electron emission from a surface. Both detectors were exposed simultaneously to nearly identical ion fluxes. By exposing only a small area of the MCP detector to ions, such that the area exposed was effectively the same as the size of the STJ detector, the number of ions detected with each detector were directly comparable. The STJ detector is 100% efficient for detecting ions in the energy regime investigated and therefore it can be used to measure the detection efficiency and secondary electron emission efficiency of the MCP. The results are consistent with measurements made by other groups and provide further characterization of the loss in sensitivity noted previously when MCP detectors have been used to detect high‐mass ions. Individual molecular ions of mass 66 kDa with 30 keV kinetic energy were measured to have about a 5% probability of producing one or more electrons when impacting the MCP. When ion energy was reduced to 10 keV, the detection probability decreased to 1 %. The secondary electron yield was calculated from the secondary electron emission efficiency and found to scale linearly with the mass of the impinging molecular ion and to about the fourth power of ion velocity. Secondary electrons were observed for primary ion impacts >5 km/s, regardless of mass, and no evidence of a velocity (detection) threshold was observed. Copyright © 2000 John Wiley & Sons, Ltd.

show abstract

Section: The Niobium Stj Detector Pulse-counting Setupmentioning

confidence: 99%

Section: The Niobium Stj Detector Pulse-counting Setupmentioning

confidence: 99%

Section: The Masked-mcp Detector Pulse-counting Setupmentioning

confidence: 99%

mentioning

confidence: 99%

“…al. 16 for more details about the operating principle of the STJ detector and its ion energy-measuring performance.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions

Westmacott¹,

Frank²,

Labov³

et al. 2000

Rapid Commun. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

show abstract

A Mass Spectrometer's Building Blocks

Westman‐Brinkmalm

Brinkmalm

2008

Mass Spectrometry

View full text Add to dashboard Cite

On‐tissue identification of insulin: In situ reduction coupled with mass spectrometry imaging

Green-Mitchell

Cazares

Semmes

et al. 2011

Proteomics Clinical Apps

View full text Add to dashboard Cite

Purpose The aim of this study was to use on- tissue reduction followed by MALDI-IMS to identify an m/z 5812.85 peak which is over-expressed in healthy human pancreatic tissue compared to Type one Diabetes (T1D) tissue. Experimental design A major constraint of MALDI-IMS is identification of compounds with m/z ≥ 4000. On-tissue reduction using tris (2-carboxyethyl) phosphine (TCEP) breaks the inter-domain disulphide bonds generating low molecular weight peptides amenable to direct MS/MS analysis. Pancreatic tissues from healthy (n=1) and diabetic subjects (n=1) were profiled by MALDI-IMS with/without reduction. Results On-tissue reduction resulted in the loss of the over expressed 5812.85 m/z peak and the simultaneous appearance of a 3430.664 m/z peak in healthy tissue. The latter peak presumably derived from the 5812.85 m/z peak was identified as the insulin B chain by MS/MS. MALDI-IMS images show that both the 5812.85 insulin peak before reduction and the 3430.664 peak after reduction co-localized with the healthy pancreatic islets. Conclusion and clinical relevance On-tissue reduction followed by MALDI-IMS resulted in the identification of insulin and localization of pancreatic islets of langerhans. The approach will be useful in the future identification of novel therapeutic molecular targets to beta-cells lost during T1D.

show abstract

Investigating ion-surface collisions with a niobium superconducting tunnel junction detector in a time-of-flight mass spectrometer

Cited by 20 publications

References 25 publications

Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions

Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions

A Mass Spectrometer's Building Blocks

On‐tissue identification of insulin: In situ reduction coupled with mass spectrometry imaging

Contact Info

Product

Resources

About