DescriptionModel 4752 - Multiplier showing installation of a single conversion dynode with dropping resistor.
Prior to August 1981, the Burle model 4750G continuous dynode electron multipliers were used on the OWA® instruments. This is a single piece assembly without the single conversion dynode or dropping resistor. After August 1981, the Burle Model 4752-OWA multiplier with a single conversion dynode and either a 50 megaohm or 25 megaohm dropping resistor was installed on OWA instruments. This newer multiplier is now standard. However, both types of multipliers are interchangeable. Finnigan MAT claims increased life with the new style multiplier. The base multipliers (Burle Model 4752-K), are the same base multipliers used in the Finnigan MAT PPINICI(TM) multipliers, with the exception of a mounting pin for the dropping resistor that has been attached to the multiplier (hence, the suffix K). The PPINICI(TM) multiplier uses 2 conversion dynodes and no resistor; the OWA style uses 1 conversion dynode and a dropping resistor. As with the PPINICI(TM) multipliers, the OWA multipliers are available in 3 modes or stages of construction.
Bare (-K)- This is the base bare multiplier, identical to the Burle 4752 except that a mounting pin for the dropping resistor has been spotwelded to the top plate. In this mode, the user must transfer the conversion dynode and dropping resistor from his old multiplier. A few small hand tools are all that is usually required. The top conversion dynode does not normally go bad unless it is mechanically damaged and can be reused many times. The complete procedure is described in Volume I of The Mass Spec Handbook of Service.
S.I.S. Conversion (-OC) - For this mode, you must send us your old multiplier. The multiplier must be of the style with a conversion dynode and dropping resistor and the conversion dynode and dropping resistor must be in usable condition. Returning one old multiplier when purchasing one new Burle multiplier covers the cost of the conversion. S.I.S. will remove the conversion dynode and resistor from the old multiplier, clean and repair them, and re-attach them to a new multiplier. All loose or broken leads will be repaired or replaced as well as damaged screens on the conversion dynode. The fully assembled multiplier will be returned to you ready for installation in your mass spectrometer.
Complete (-OWA) - The complete OWA multiplier is no longer available from S.I.S.. Finnigan MAT retains the patent on this multiplier and chooses not to supply us with the necessary parts.
Old Style (-No Suffix) - The Burle Model 4750G is the complete multiplier used in the early models of the OWA instruments prior to August 1981. A conversion dynode and dropping resistor are not present, (nor are they required). The multiplier is complete and ready for installation in the mass spectrometer.
Burle - The Burle multipliers are the original continuous dynode electron multipliers used by Finnigan MAT in all the OWA instruments.
All models come with a one year prorated warranty.