Miniaturized two sector field analyzer for complex electro-spray source mixture separation and ion-CCD visualization prior to micro-array simultaneous deposition
EMSL Project ID
42293
Abstract
My research interest will explore the feasibility of fusing a miniaturized double focusing tandem sector field to an ESI type source for simultaneous dual functionality, first, simultaneous separation of complex mixtures, and second, hyperthermal deposition in a micro array fashion. Being pressure independent, the Ion-CCD would be suitable in harsh-environment operations making it ideal for ion-beam characterization. This said, The Ion-CCD would be mounted directly after the collisional and resolving quadrupole to monitor the respective beam profiles. My proposed system will be a small part of the full OI Analytical transportable mass spectrometer. Such a "stand-alone" analyzer will contain a 100 um wide object-slit plate, a 5 cm radius electrostatic analyzer (ESA) and a 1 Tesla permanent magnet with a 1.5 mm "ion-fly" gap. Located on the focal plane of the analyzer is a 5 cm long Ion-CCD type detector used to detect simultaneously the separated compounds focused in ~ 1500 x 300-mm2 spots along the analyzer focal plane. The Ion-CCD is an array detector containing 2136 active pixels, each with a 21 um width and 3 um spacing, and hence with a 24 um pitch. The Ion-CCD generates mass spectra of the simultaneously detected ions as frames with intensities proportional to the Ion-CCD exposure time. The maximum rate of the detector operation is 360 frames/sec. The detector has a very good linear response as function of beam intensity as well as exposure time or CCD integration time. The exposure or integration time can be set between 80 us and 5 sec producing a signal amplification of about 4 orders of magnitude. The whole analyzer together with the ion-CCD will occupy a volume of 6 cm x 12 cm x 24 cm (H x W x L), just the right dimensions to fit in vacuum chambers where most commercial quadrupole mass filters are used.Addition:
Though the above proposal was successful in producing valuable data, some key data are missing to finalize our paper, which is in preparation. The previous experiments were performed using a 200 um slit width of the analyzer to ensure sufficient signal at the detector but in the same time reducing the analyzer resolution. The Analyzer will be retrofitted with a 100 and 50 um slits to provide better-resolved structure in mass spectra. This latter would help extract the energy distribution of ions exiting the collisional quadrupole hence tuning the system with narrower distributions. Furthermore the previous experiments used a grounded analyzer and array detector which limited the m/z detection window of the system. This addition will include a floated analyzer detector to expand the detection window without stressing the collisional quadrupole standard operational settings.
Project Details
Project type
Limited Scope
Start Date
2010-09-01
End Date
2010-11-01
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Hadjar O, GE Johnson, SM Shill, G Kibelka, K Kuhn, and J Laskin. 2010. "IonCCD for direct position-sensitive charged particle detection: from electrons and keV ions to hyperthermal biomolecular ions." PNNL-SA-74824, Pacific Northwest National Laboratory, Richland, WA.