Cooling of direct current beams of low mass ions

Koslovsky, V; Führer, Katrin; Tolmachev, Aleksey V.; Dodonov, A. F.; Raznikov, V. V.; Wöllnik, H.

doi:10.1016/s1387-3806(98)14154-4

Cited by 15 publications

(12 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Simulated ion trajectories in the multipole are also shown in this ®gure. Application of collisional cooling to lowmass beams (Koslovsky et al, 1998) and a theoretical model for collisional focusing (Tolmachev et al, 1997) have been presented recently.…”

Section: Ion Beams Involving Supersonic Expansionmentioning

confidence: 99%

Orthogonal acceleration time-of-flight mass spectrometry

Guilhaus

Selby

Mlynski

2000

Mass Spectrom. Rev.

310

197

View full text Add to dashboard Cite

The principles and applications of time‐of‐flight mass spectrometry involving instruments with independent (orthogonal) axes for ion generation and mass analysis are reviewed. This approach, generally referred to as orthogonal acceleration time‐of‐flight mass spectrometry, has proved particularly advantageous for the combination of continuous ionization sources with time‐of‐flight mass spectrometry. The history of the technique is briefly discussed along with the instrumental principles pertaining to all the stages of the instrumentation from ion source to detector. The applications of commercial and customized instruments are discussed for several ionization methods including electrospray, matrix assisted laser desorption/ionization, electron ionization, and plasma ionization. © 2000 John Wiley & Sons, Inc., Mass Spec Rev 19: 65–107, 2000

show abstract

Section: Ion Beams Involving Supersonic Expansionmentioning

confidence: 99%

Orthogonal acceleration time-of-flight mass spectrometry

Guilhaus

Selby

Mlynski

2000

Mass Spectrom. Rev.

310

197

View full text Add to dashboard Cite

show abstract

“…Mass resolution, as illustrated for m/z 264, has also increased. This indicates that collisional cooling is occurring in the quadrupole ion guide [11,12]. Subsequent addition of more helium led to a decrease in intensities of all ions.…”

Section: Instrument Performancementioning

confidence: 94%

Miniaturized EI/Q/oa TOF mass spectrometer

Berkout

Cotter

Segers³

2001

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

A miniaturized orthogonal time-of-flight mass spectrometer with an electron impact ionization ion source and a rf quadrupole ion guide has been developed. A mass resolving power of m/⌬m ϭ 5500 has been obtained in a 0.4 m instrument. The addition of helium at pressures of about 4.0 mtorr into the ion source showed collisional focusing taking place in the rf quadrupole. An automated gas chromatograph designed for air monitoring applications has been coupled to the time-of-flight mass analyzer and tested for the detection of simulants of chemical-warfare agents. A dvanced easily portable chemical sensor systems are essential for the on-site analytical measurements required for a variety of diverse applications such as environmental characterization and monitoring, law enforcement, and chemical emergency response. For such applications, mass spectrometry-based systems that combine laboratory performance with high portability and robustness are required. Time-of-flight mass spectrometers (TOF-MS) look promising for realization of these goals because of their simple designs and rapid delivery of full mass spectra. However, the fact that limited mass resolution m/⌬m (up to a few hundred) has been obtained with electron impact ionization has limited their applications for the analysis of volatile and semi-volatile chemical compounds.The major limitation comes from the initial velocity distribution of ions created by electron impact in the storage ion source [1], and particularly the inability to compensate for the turn-around time described early on by Wiley and McLaren [2]. The mass resolution of the TOF can be increased by the addition of an ion mirror [3]. An ion mirror images the McLaren space-time focus plane to the plane of the ion detector in such a manner that ions with differing energies (but the same mass) will arrive at the detector at the same time. The resolution of this type of instrument, when coupled to a gas chromatograph, is still limited because of a continuous gas load to the ion source located in the analyzer chamber. With this technology a mass resolution of about 700 was obtained on a 1.5 m long TOF instrument [4].An alternative approach consists in forming the ion beam in a direction which is perpendicular to the time-of-flight direction. The original velocity spread in the longitudinal direction no longer affects the arrival time of an ion packet on the detector. An orthogonal injection TOF was first proposed in 1964 [5] but has been reintroduced as a method for improving mass resolution [6,7]. A mass resolution of m/⌬m Ͼ 10,000 was demonstrated recently in a 1.2 m long instrument with an orthogonal electron impact ion source and ion mirror [8].In this paper we present a compact time-of-flight mass spectrometer with an orthogonal electron impact ion source. An rf quadrupole used as an ion focusing element allowed us to achieve high mass resolving power at elevated pressures in the ion source housing. To demonstrate the potential of orthogonal-extraction, time-of-flight mass spectrometer for air...

show abstract

“…Transmission losses at large ion energies have been previously reported in several cooling experiments [2]. For Ar + ions the decrease in transmission with increasing ion energies may be due to a combination of two effects: (1).…”

Section: Discussionmentioning

confidence: 63%

“…The transmission measurements were conducted at a fixed buffer gas pressure of ~2.3 Pa. As the ion energy is increased, the gas pressure is not sufficient for damping the motions of ions and thus, an increasing number of ions will less likely pass through the small exit aperture. (2). At high energies, collisions with buffer gas may lead to scattering losses of ions during transport through the quadrupole.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Collisional cooling of negative ion beams

Liu

Liang

Alton

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

View full text Add to dashboard Cite

Investigations have been conducted to determine the feasibility of using collisional cooling for reducing the energy spreads and, consequently, the emittances of negative-ion beams. We have designed a gas-filled RFquadrupole ion cooler equipped with provisions for retarding energetic negative ion beams to energies below thresholds for electron detachment at injection and for reacceleration to high energies after the cooling process. The device has been used to cool O -and F -ion beams with initial energy spreads, ∆E > 10 eV to final energy spreads, ∆E ~ 2 eV FWHM. Overall transmission efficiencies of ~14% for F -beams have been obtained. Experimental results show that electron detachment is the major loss mechanism for negative ions.

show abstract

Cooling of direct current beams of low mass ions

Cited by 15 publications

References 4 publications

Orthogonal acceleration time-of-flight mass spectrometry

Orthogonal acceleration time-of-flight mass spectrometry

Miniaturized EI/Q/oa TOF mass spectrometer

Collisional cooling of negative ion beams

Contact Info

Product

Resources

About