ESHQ Radiation Physics Engineering: New Safety System and - - PowerPoint PPT Presentation

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ESHQ Radiation Physics Engineering: New Safety System and - - PowerPoint PPT Presentation

Feb 04, 2024 11 likes •307 views

ESHQ Radiation Physics Engineering: New Safety System and Instruments Adam Olson Engineer Retreat Engineering within Fermilab 20 February 2018 New Safety System and Instruments Presentation Topics for this presentation The design of

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Adam Olson Engineer Retreat – Engineering within Fermilab 20 February 2018

ESHQ Radiation Physics Engineering: New Safety System and Instruments

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New Safety System and Instruments Presentation

  • Topics for this presentation

– The design of a new PLC-based, rack-mounted, ODH safety system – The design of a new radioactivity classification instrument – The design of a new interlocked radiation area monitor instrument

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New Oxygen Safety System Project – Interlocks Team

  • Design a new hybrid system based on existing ODH systems

– Combines the advantages of the current rack-mounted ODH system with beneficial features from the current PLC-based ODH system

  • Advantages of the existing rack-mount system:

– Simplified use, lower cost, smaller size and portability

  • Advantages of the existing PLC system:

– More reliable oxygen sensor, industry-standard safety rated components, and computer processing capability

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New Oxygen Safety System – PureAire Sensor

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  • PureAire sensor chosen for the new system

– Zirconium oxide sensor not dependent on barometric pressure – 10 year cell expiration – 4-20mA current loop interface

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New Oxygen Safety System – Helium Sensitivity Error

  • PureAire sensor is sensitive to helium in the air

– Reads higher than normal oxygen in the presence of low levels

  • f helium – this is an unsafe condition
  • Empirically derived look up table to compensate for an

assumed ever-presence of helium

– Piecewise linear curve with four inflection points across the measurement range – Thousands of data points can be programmed with a PLC

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New Oxygen Safety System – Helium Compensated Data

  • Application of the helium compensation curve to the raw data

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New Oxygen Safety System – Block Diagram

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New Oxygen Safety System – Prototype Internal

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New Oxygen Safety System – Readout and Interface Panels

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New Oxygen Safety System – Prototype Front Panel

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New Oxygen Safety System – Benefits

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  • Benefits

– Reduces the number of false alarms under the current rack- mounted system – Reduces maintenance and calibration costs – Cheaper to install than the full PLC ODH system – More portable than the full PLC ODH system – Uses a safety rated PLC – Barometric pressure independent sensors – Helium compensated measurement for unsafe condition

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Wallflower 4 Project – Instrumentation Team

  • The humble Geiger counter with some bells and whistles
  • Replaces the original, 40+ years old wallflowers designed by

physicist Bob Shafer

  • Fulfills instrumentation needs of radiological workers at

Fermilab

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Wallflower 4 – Prototype Unit

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Wallflower 4 – How it works

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Wallflower 4 – Mechanical

  • Housing modifications

– Fit everything in a portable housing that can take abuse in the field – Machining of the plastic housing

  • 3D printed parts

– 3D printer (MakerBot Replicator) custom parts – Precise alignment of GM Tube, check source, and sonar transducers

  • Custom overlay with integrated push button and transparent window

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Wallflower 4 – 3D Printed Components

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Wallflower 4 – Assembled Prototype Internals

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Wallflower 4 – Prototype PCB

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Wallflower 4 – Software

  • Embedded system programmed in C

– No operating system → creation of Wallflower Board Support Package (BSP): – Modular C units sharing memory, data, interrupt time, and hardware resources – No dynamic memory allocation allowed

  • Embedded Rad Instrument

– Abstraction of the radiation instrument to the application programmer

  • Makes it easier to build up new instrument configurations without code restructuring

– USB communication and the instrument’s serial protocol – Calibration/testing applications vs. the end user application

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Wallflower 4 – Benefits

  • ALARA-friendly goals:

– Reduce user error in measurement and classification of items – (Future) Reduce process duration with statistical analysis (standard error) to complete measurements just-in-time.

  • Directly measures a standard reference for the radiation

intensity with the sonar distance.

  • Transformable, portable, modular BSP:

– New graphics, fonts, peripherals, process pages, scales/units, USB commands and more could be changed to make a completely new instrument with the existing design. – If the Fermilab Rad Worker procedure changes, the instrument could be adapted in software.

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New Area Monitor Project – Instrumentation Team

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New Area Monitor – Design Committee

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  • It will replace the Chipmunk and Scarecrow radiation area

monitors all over the lab

  • Fulfills the needs of RSOs to interlock radiation areas
  • Created a committee for future radiological instruments with

stakeholders from ESHQ teams:

– Instrumentation – Interlocks – Radiation Safety Officers – Radiation Physics Science team

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New Area Monitor – Instrument Simplification

  • Quality Factor-less

– Exact weighting factors will be determined by the RSO and applied directly in the interlock’s trip setting without any need for configuring the instrument hardware

  • Uniform dose per pulse in units of 1 µrad to simplify math and

instrument configuration

– Inspired by the FOX x-ray area monitor with 1µR/pulse

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New Area Monitor – Prototype

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  • Prototype made from a Chipmunk yellow box with new guts
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New Area Monitor – Hardware

  • Environmentally rugged specs

– -30 ° to +50 °C operating temperature – 93% Relative Humidity at 30 °C – EMI and ESD protection

  • Surface mount digitizer board

– New Texas Instruments electrometer opAmp – LMP7721 – Active guard ring to minimize leakage – Minimize parasitic effects on layout – No floating components – Sensitivity of 2pC/count working

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New Area Monitor – Digitizer Prototype

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  • Electrometer with active guard ring around its input
  • Case with gasket, grease seal, and desiccant plugs to keep
  • ut moisture
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New Area Monitor – Control Board Prototype

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New Area Monitor – Benefits

  • Flexible weighting factors
  • Higher output sensitivity, uniform dose/pulse of 1 µrad

compared to Chipmunk.

  • Lower power draw
  • Reduces black magic required to build and fix digitizers
  • Dual power, option to not need electrician work
  • Smaller physical size
  • Recycles the Chipmunk ion chambers
  • Cheaper unit cost
  • (Future) Expandable IO with the FPGA

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The End

  • Thank you for your time!

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