GC-HR-ToF Instrument overview 7/16/2015 JDC

Instrument Systems

Windows computer Primary user interface to instrument Run QNX virtual machine – interface to QNX system Control TPS via web interface (TCP/IP) Collect ion data from MCP via preamp and ADC (ADQ 1600)

Gas Handling/Cal box Mass flow controllers Ion source N2 (500 sccm FS) Ion gas CF3OOCF3/N2 (5 sccm FS) Dilution N2 (3 slm FS) Ambient zero (1 slm FS) Two types: digital STEC, analog STEC/MKS both powered by +/-15V, digital are set and read via RS-485 which can be daisy-chained from single serial port. Analog are set by DAC-controlled analog voltage, and readback is recorded by reading an analog voltage via ADC.

Gas Handling/Cal box Pressure controller STEC digital pressure controller to control pressure of gas in the cal system to ~2 bar. ~500 sccm maximum flow rate Pressure readback digitally via RS485 (same chain as MFCs) Pressure set with hardwired analog voltage stepped down from +15V power source, so the setpoint is always applied with there is power to the controller.

Gas Handling/Cal box Hot Calibration system On the flight instrument we’ve used a eutectic metal controlled to a temperature just above the melting point (~48C) in an insulated system with a large heat capacity, so that temperature is maintained for ~24hrs after power is turned off. For this system which will not fly on airplane, power should be on all the time, thus we don’t need the metal bath. Suggest designing an insulated oven which can hold ~4-5 permeation tubes, with temperature control from (~amb-70C) using heater, RTD and Watlow temperature controller. We now have driver for PM6 digital watlow which allows setpoint to be set and read via RS485 (separate port from STEC) Traditional calibrants have been formic and acetic acids, and HNO3. Hope not to use HNO3 in future, but rather the hydroxy nitrate of propene.

Gas Handling/Cal box Pressure gauges MKS 750B model – compact absolute (capacitance) sensors 1000 torr FS (flow-tube) 100 torr FS (flow-tube) 100 torr FS (flowtube pump) These are powered by +24VDC, give analog voltage output which is read by ADC. To improve stability these have been insulated and heated to above ambient ~40C using heater and heaterstat. This is particularly important for the 100 torr flowtube gauge used to control the ambient flowrate. Differential pressure gauge (MKS) used with pitot tube to measure flow velocity in the inlet.

Gas Handling/Cal box Athena III SBC ( Single board computer with serial ports (4), digital IO (24),analog in (16), analog out (4). We have put this into the Pandora enclosure system for protection Powered by +5VDC Seamless communication with primary Hercules board via TCP/IP

Athena BB board Signal routing/connector board for Athena I/O Combines analog IO, digital IO, and power into connectors for individual devices.

Gas Handling/Cal box Ion reagent gas bottle On aircraft instrumentation this had to be enclosed inside a pressure vessel vented to the outside of the airplane. For this instrument this is not nessisary, but mounting for 3 bottles inside this box will be good, then these will not need to be switched out over a deployment. Ultraclean regulator for CF3OOCF3 bottles CF3OOCF3 shutoff valve Electronic pressure gauges (high and low) for regulator External mounting of bicarb filter for the CF3OOCF3 line so that it can be easily changed

Gas Handling/Cal box Manual shut-off valve for N2 upstream of MFCs

Gas Handling/Cal box Valve driver board: 5-channel cooldrive board to switch the Nresearch valves on/off Power +5V, +24V Signals +5V digital signals, note Athena digital lines are +3.3V, so these need to be converted to +5V These are to control: Zero valve Cal – bypass valve Cal – scrub valve Individual calibration gasses if needed

GC-Control Box Mass flow controllers Dilution flow Bypass flow ? STEC digital MFCs

GC-Control Box Athena III SBC (same as described above)

GC-Control Box Watlow temperature controllers PM6 – single setpoint control (optional pre-trap, or transfer line) F2 – ramping controller (main column ramping control)

GC-Control Box Valve driver board (cooldrive): CO2 cooling valve Nresearch Teflon valves (collection / elution, others?)

GC-Control Box Temperature sensors: Thermocouples? Perhaps we should move to RTD?

GC: Column Oven Resistive Heater CO2 cooler Temp sensors Valve to switch between collection and elution Suck back valve or MFC to capture gas during collection Pump – what is needed? Bypass flow Suck/backflow

Analog digital converter: SP devices ADQ 1600 ~ $24, Power: 12V Input voltage range: +0.2V to -2.0V: Do not exceed. Speed: 1.6 GSPS 14-bit Control and data transfer by ToFWerk DACRecorder via USB signals

ToF Power Supply - bipolar (Tofwerk) Lens voltages Pulser voltages Reflecton voltages MCP voltages Power: 120VAC/60Hz Ethernet control

Boxes: In the past we’ve used frontpanel express. They are a bit expensive, but SW tends to be easy to use, and product is nice, and we only make a few.

Front Panel express