PlasmaQuant MS Series
Electronics
179
Three custom made high vacuum HV feedthroughs provide an interface for the two
EHT supplies and the dilutor supply to enter the vacuum chamber. The EHT and the
attenuator output connectors on the attenuator control PCB mate directly with the
three high vacuum HV connectors fixed to the vacuum chamber detector panel.
Three insulated wires connect the detector terminals with the high vacuum
feedthroughs.
The power supply for the two exit plates, the fringe rods and the two entrance
plates enters VC3 by a military style high vacuum connector. It is positioned in the
removable top panel of the vacuum chamber#3.
Four conductive strips provide a contact surface between the mass analyzer
assembly and the removable vacuum chamber top panel.
The conductive strips are made from Beryllium/Copper and four stainless steel
wires insulated with PTFE tube connect the strips with the feedthrough connector.
The output signal from the detector is connected to the discriminator PCB by via a
high vacuum signal feedthrough SMA connection.
The discriminator signal output is connected directly to the systems control PCB.
This loom also carries the +15 V and two -15 V. It is terminated at each end with
RJ45 connectors.
The attenuator is controlled by the system control PCB to vary the voltage on
dynode 4.
The Electrical Box module supplies mains power to the quadrupole controller. The
mains switching relay, located inside the Electrical Box, and is activated by a +24
Volt signal from the systems controller PCB.
The quadrupole controller receives commands from the system control PCB to
control the ratio of RF and DC power supplied to the quadrupole assembly.
A single loom carries the error signals and the RF and DC commands from the
system control PCB to the Quadrupole controller. This loom is terminated at the
upper side of the Quadrupole controller at a 9-pin D-range connector.
The quadrupole controller delivers the RF and DC signals to the quadrupole
assembly by two coaxial cables terminated at the mass analyzer at gold plated
banana plug connections.
10.2.5
Communication Functionality
The PC to instrument communication interface is via USB. The system control PCB
contains all the electronics responsible for USB communication.
The interface between the PC and the systems controller PCB occurs by the USB and
Accessory interconnect PCB mounted on the rear chassis of the instrument. A standard
USB cable connects the systems controller PCB to the interconnect adaptor and a
second standard USB cable connects the interconnect adaptor with the PC.
For troubleshooting purposes the USB cable can be connected directly to the systems
controller PCB. The interconnect PCB simply serves as an interface.
Attenuator/discriminator
Quadrupole controller