HPQ2-IP SP101009.102 – 10 October 2012
MKS Instruments, Spectra Products
27
CAUTION
THE QUADRUPOLE’S FILTER IS ACCURATELY
ALIGNED BY
SKILLED PERSONNEL USING
SPECIALIST TOOLS AND JIGS.
UNDER NO CIRCUMSTANCES SHOULD THE FILTER ASSEMBLY BE
DISMANTLED.
IF YOU ARE IN ANY DOUBT WHEN SERVICING YOUR ANALYSER,
PLEASE
CONTACT YOUR LOCAL SERVICE CENTRE.
In the remainder of this section we describe how to replace filaments, replace the
ion source and clean the ion source as an assembly. The HPQ2-IP analyser has
been designed to allow these jobs to be carried out with minimal training and
specialised equipment. Further analyser maintenance, is not described in this
manual as we feel this is only possible after training by Spectra personnel. If you
have any doubts about analyser maintenance please call you local Spectra facility.
7.3 Failed Filaments
The filament status is constantly monitored by the power supply electronics and the
operating software. This is done by measuring the flow of electrons emitted by the
hot filament, referred to as the emission current, and flowing to the ion source
cage. This is normally maintained at a fixed value between 0.1mA and 1mA. The
current flow through the filament is increased until the value of emission current is
reached. If, however, the control electronics reaches the limit of its filament current
supply capability and the emission current has still not reached the required level a
filament fail condition will exist. In the vast majority of cases this will be due to a
blown filament, more correctly described as an open circuit filament. There are
conditions such as a heavily contaminated ion source which will result in a filament
fail when the filament is not open circuit. So, checking that the filament is open
circuit is worth doing before going to the trouble of removing the analyser from
your vacuum system.