Supplies and Services for Mass Spectrometers, Gas Chromatographs
and Liquid Chromatographs
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Burle Channeltron Electron Multipliers
Analytical instrumentation of many types contain Burle Channeltron Electron Multipliers, including: soft X-ray spectrometers, VUV spectrometers, magnetic sector and quadrupole mass spectrometers. Channeltron Electron Multipliers are the detectors of choice for scientists and scientific equipment manufacturers worldwide. High-performance applications demand high detector sensitivity, reliability, value and long useful life. Channeltron Electron Multipliers deliver high performance. Burle multipliers are the preferred multiplier for mass spectrometer use. In-house glass production, materials research and applications engineering allow Galileo to test the limits in custom design and fabrication. A 100% test and inspection policy guarantees customers the highest quality and most reliable detectors available in the world. 4700 Series These high-current detectors are designed for use in the analog current measuring mode. Designed to reach high performance at >25µA bias current, the 4700 Series detectors are the most widely used quadrupole mass spectrometer detectors in the world. Channeltron® 4700 Series detectors are available mounted in ceramic housings and are bakeable to 350 degrees C. 4800 Series These high-current/high gain detectors are designed for use in either pulse-counting or analog mode. Typically, a 4800 Series detector has 10X higher gain than 4700 Series detectors and an output pulse height distribution of less than or equal to 75% FWHM. The 4800 Series are available mounted in ceramic housings and are bakeable to 350 degrees C. 5700 Series These are the new high performance detectors for mass spectrometers. They are designed for higher sensitivity, extended dynamic range and longer detector life. Parameters Analog Pulsed 1. Pulse Width - 18-20 nSec 2. Rise Time - 3-5 nSec 3. Dark Count Rate <.05 cps <.05 cps 4. Linerarity ~10% of bias current - 5. Bias Current 25-46µA 15-35µA 6. Maximum Count Rate - 107 cps 7. Gain @ 3000V >107 >108 8. FWHM - <75% Burle Multipliers in stock for immediate shipment
T he Burle Continuous Dynode Electron Multipliers (CDEM) are available for most mass spectrometers. The Burle Channeltrons® are made of a continuous strip glass dynode structure with a high resistance coating. The 4700 series multipliers were originally designed for mass spectrometer manufacturers and are currently used by Finnigan/Mat, DuPont, Hewlett-Packard, and others in the manufacture of their mass spectrometers. The 4700 series multiplier is a direct retrofit for existing CuBe multipliers in mass spectrometers and is rapidly becoming the standard detector in the industry due to its excellent air stability. The 4700 series models are designed to operate in the analog (current) mode. The 4800 series are designed to operate in either the analog or pulsed (digital) mode. The normal life of multipliers is one or two years depending on the use (and abuse) of the mass spectrometer. Lives of over four years have been reported by users through careful use. The Burle multiplier in the Saturn space craft is expected to have a life of over eight years. Shelf-life of a Burle multiplier is expected to be at least two years if kept in its original sealed package or in a vacuum desicator until required for use. However, multiplier warranty is one year from the date of purchase. All Burle multipliers for mass spectrometers are stocked by S.I.S. for emergency shipment to our customers avoiding unnecessary stocking by our customers. Multipliers can be shipped via UPS Ground, UPS Next Day, Federal Express or Airborne. The Use of Channeltron® Detectors
The Channeltron® Electron Multiplier has a history of dependability in mass spectrometer applications. The following instructions and precautions are presented here in order that the user can achieve the maximum useful lifetime of a Channeltron detector. 1. Mounting work should be done in clean vacuum fashion, i.e., the detector should be handled with talc free finger cots or lint free gloves. Care should be taken to avoid dust, lint, or other particulate matter. Nothing should touch the active areas of the detector. .2. Channeltrons are normally operated at pressures of 10-5 or lower. Higher pressure operation is observed to increase the background current and can result in shortened life. Do not apply high voltage at pressures greater than 10-4 torr as arcing can occur and permanent destruction of the Channeltron surface is possible. 3. Channeltrons are customarily operated at 1500 to 3000 volts. The maximum rated voltage difference between input and output leads is 3000 volts. Care should be taken to operate at a voltage which gives sufficient gain to achieve acceptable results. Higher gains will shorten Channeltron lifetimes in inverse proportion, i.e. 2x the gain results in 1/2 the potential lifetime. 4. During the first few days of operation of a new detector, it is recommended that high output currents be avoided (i.e.inputs above 10-9 amps while operating at gains in excess of 107). Taking this initial burn-in precaution can prevent premature failure. 5. Backstreaming from oil diffusion pumps or roughing pumps should not be permitted. It is recommended that cold traps and molecular sieve traps be operated and maintained to manufacturers specifications.
Channeltron® is a registered trademark of Burle Electro Optics
Corp.
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