This Time Of Flight mass spectrometer (TOFMS) is designed for optimum use with resonance-enhanced multiphoton ionization spectroscopy in supersonic beams. Use of the supersonic beam results in a great improvement in resolution, i.e., at least 800 at mass 93. Ion packets on the order of 10 nanoseconds have been observed on the flat dual channel plate detector. Resolution appears to be pulse width limited.
Our Pulsed Supersonic Valve (PSV) generates a fast-pulsed molecular beam using reservoir pressures greater than one atmosphere with a large orifice (0.5mm). This gives high on axis intensity for maximizing the photoionization signal. The short pulse length of this valve (55 microseconds) allows modest pumping capacity.
A skimmed beam, differential pumping and a liquid N2 shroud maintains the flight tube on the order of 5X10-7 Torr and eliminates organic contamination from the ionization region. This also results in low maintenance. The ionization source should operate for years without cleaning. Standard UHV flanges, components and construction techniques are used throughout. This gives design flexibility and allows later changes if desired.
The chamber can be furnished to mate with the user's vacuum system flange, or in some cases, the instrument has been modified to fit into the user's existing vacuum chamber.
B-654 TOF SOURCE ASSEMBLY (LN COOLED). Ion source elements are enclosed in a gold plated thick wall copper shroud which is normally bolted to the bottom of the D-653 Cold Trap Assembly. Being surrounded by a cryogenic baffle reduces the background due to backstreamiong of condensable vapors. Since the source elements are also optically baffled, the ion source can be kept clean and maintenance free, usually for years.
C-686 FLIGHT TUBE is a 6 inch CONFLAT nipple using 3 inch diameter electropolished stainless steel tubing. Used to extend the flight path length of our TOF Mass Spectrometer. Usually mounted between the detector C-701 and Sideport Tee C-687 on top of the D-653 Cold Trap.
C-687 SIDEPORT TEE has a 6 inch CONFLAT flange for attaching a vacuum pump to the flight tube of either of our linear TOF instruments. An additional 2.75 inch port is located opposite the pump for mounting gauges, etc. When used in conjunction with the B-682 Shroud, the ion source, flight tube and detector can be differentially pumped to well below chamber pressure.
C-701
18mm MCP DETECTOR ASSY is mounted on a 6 inch O.D. CONFLAT flange
with 50 Ohm Anode. A ground potential input grid presents a flat,
field free plane to the incoming ions. Two chevron mounted 18mm
microchannel plates provide high gain (10e7) with sub-nanosecond
rise time. Mating connector to the 50 ohm anode is furnished.
Shipped mounted on a 6 or 4½ inch Conflat flange, baked
and pinched off in its own vacuum housing.
A special high sensitivity configuration is available.
D-603
TOF POWER SUPPLY is a single compact source for all the voltages
used in a typical Time Of Flight Mass Spectrometer. Choice of
this unit should curtail instrument clutter in the immediate vicinity
of the experiment. All voltages are monitored by the same meter.
A voltage is only displayed while its monitor button is depressed.
Each end of every cable is labeled to match the receptacle to
which it connects.
TOF Power Supply Manual (PDF) Click
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To download, right click on link and "save target as".
Filesize: 210 KB.
Manual includes power supply specs and the operation procedure
for the Time of Flight Mass Spec.
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