ESI Model 20 Ion Chamber EVOLUTION OF THE ION CHAMBER HPIC Meeting September 25, 2012 Presented by Jim Shiley

 Some of the oldest and most widely used types of radiation detectors are based on the effects produced when a charged particle passes through a gas.  Ion chamber instruments are, in principle, the simplest and therefore most reliable of these detectors. BACKGROUND

 As a fast, charged particle passes through a gas, it interacts with neutral molecules resulting in an ion pair (positive ion and free electron).  This can occur by direct or indirect interaction.  The number of these interactions is a remarkably constant parameter given the gas and type of radiation.  In the presence of an electric field, the ion pairs will migrate or drift.  This drift of ion pairs creates an electric current, which can be measured. HOW AN ION CHAMBER WORKS (OVER) SIMPLIFIED VERSION

 The ion chamber is the standard workhorse of portable ion chamber survey instrumentation.  Used to determine dose rates and thereby stay times  Essential to ensuring safe work environments.  Eberline Services has been working to redesign this instrument, keeping the full functionality and familiar look and feel while making the unit safer and more user friendly. ION CHAMBER EVOLUTION

 Assume that the ion chamber instrumentation can be updated and improved  Get input from users; ESI has a large internal pool of users in our own RCTs and IHTs  Insert new electronics and improve data processing  Reduce weight  Move beyond survey usage  Enhance data collection  Use ESI background in field applications and other developments, e.g. field surveys, GPERS, etc. CAN MATURE INSTRUMENTS BE IMPROVED?

 GPERS composite technologies are continually updating and improving.  Miniaturization of individual modular components of the GPERS system has allowed the weight burden to be reduce to < 8 pounds!  Surveyor safety is improved greatly with its lightweight and diminished size (integrated system almost unnoticeable for surveyor and allows near uninhibited agility). GLOBAL POSITIONING ENVIRONMENTAL RADIOLOGICAL SURVEYOR

 Data is collected or monitored:  Locally to a data logger with display to monitor a trace of his survey path and current radiological readings in real- time to verify coverage of any given area. Areas that exceed a user-set radiological trigger point activate an audio cue and are visually highlighted to provide instant notification.  Transmitted via Bluetooth® to a local wireless network/cloud.  Real-time data classification and analysis can be conducted remotely and simultaneously with field teams. GPERS ENHANCEMENTS

 Lightweight yet rugged and with improved accuracy.  All system components performed without incident while surveying robotically in a 150 R/hr area.  Improved data accuracy quality in a quicker time frame makes “informed” project managers resulting in better efficiency and cost savings.  Large data sets rendered to virtually any AutoCAD or GIS format provides easily understandable graphical representations of otherwise quite an overwhelming volumes of data. GPERS ADVANTAGES

GPERS MAPS - CHARACTERIZATION SURVEY

GPERS MAPS – FINAL STATUS SURVEY

 Instrument primarily used for quick surveys not extensive data collection  Users like an analog display rather than digital  Ergonomic improvements were not considered important  Went through several variations on handles, but users liked old style  Durability is important.  Familiar packaging styles was preferred  Calibrations important  Reliable battery power important  Weight reduction is a good goal FEEDBACK FROM USERS

ESI MODEL 20 ION CHAMBER

 Older generation instruments used taut-band meters that were susceptible to movement-induced needle wobble. New instruments utilize microcontroller / gear-reduced stepper motor design to eliminate the wobble while keeping the familiar look.  Temperature and pressure sensors are used to automatically compensate the readings, alleviating the user from tedious manual corrections for atmospheric pressure. ESI MODEL 20 ION CHAMBER

 Consumable materials, such as the desiccant, are viewable without opening the case.  Rechargeable batteries reduce the need to open the instrument case.  Access within the case is easier, including a threaded chamber with no attaching cable, which allows extremely easy replacement.  The instruments are getting lighter. ESI MODEL 20 ION CHAMBER

 Most important, the new generation ESI Model 20 is calibrated from a computer through the USB port.  This allows all ranges to be calibrated quickly from a single point and reduces the exposure of the calibration technician to the calibration sources.  User-definable settings can be set at the same time and stored in the non-volatile memory. CALIBRATION

CALIBRATION SCREENSHOT

 ESI Model 20 provides a recognizable instrument easily useable by personnel experienced in ion chamber meters.  However, unit is a platform for more extensive usage.  Digital operation allows expansion of capabilities.  Can be used for data collection. NEW PLATFORM

QUESTIONS?