Harshaw TLD Model 8800, High Capacity Auto System

The precisely controlled heating profiles offer consistent, repeatable glow curves, suitable for further analysis.

Performance highlights

• Measures beta, gamma, X-ray and neutron doses, singly and mixed
• Automatically reads a carousel containing up to 1400 four-element cards at 140 cards per hour
• Dosimeters and algorithms meet international accreditation requirements including all DOELAP and NVLAP
• A unique health physics record system tracks and maintains records
• Precise, highly controlled, highly reliable linear heating by gas:
  -Produces uniform heating
  -Provides better reproducibility
  -Extends dosimeter life
• Host computer with VGA color monitor
• Menu-driven control of "expose", "transport cards", and "diagnostics"
• Explicit on-screen text -no cryptics
• Optional ⁹⁰Sr internal irradiator
• Optional UPS prevents loss of data during power failures
• Field-proven reliability.

Cutaway front view of the Model 8800 Card Transport (below)
	A.200 Card Load Stack shown with 50 cards loaded B. 8-stack Load Carousel C. TLD Card on Transport Rack D. Bar Code Reader Station E. Photomultiplier Tube Assembly F. Heating Station G. 90Sr Irradiation Station option H. Unload Carousel I. 200 Card Unload Stack

PMT clean-out drawer The photomultiplier tube assembly is accessed for inspection or cleaning, as required, via a small clean-out drawer.
Hot gas flow control The precise flow of hot gas to the four heater tubes for the TLD dosimeter elements is controlled by four precision flowmeters adjusted and balanced during factory setup. High Voltage Potentiometers (not pictured), are mounted within the Reader, allowing precise adjustment.
Back panel computer interface The back panel controls include a keyboard enable/disable switch and the following connectors: Keyboard Mouse Screen Serial port Parallel printer port.
Model 8800 TLD Reader's hinged panels The carousels and clean-out drawer are accessible through hinged panels in the cover. The whole cover is entirely removable in one piece to access all internal parts without disconnection. The transport mechanism is mounted on slides for very easy access to the moving parts.

• Set the Reader's acquisition parameters
  
• Implement quality assurance
  
• Generate and maintain Reader and Dosimeter calibrations
  
• Store and review TL data
  
• Report in ready-to-file formats.
  

WinREMS is suitable for whole body, environmental and extremity monitoring applications and interfaces with other Harshaw TLD software and other data processing equipment.

WinREMS is suitable for networking:

• Different Reader models can share data with a central file server host
  
• Any networked Reader can generate calibrations
  
• Common databases can be used by Readers
  
• ASCII data can be tranferred in user-defined formats, and used with user-developed programs or products of the Harshaw TLD line.

WinREMS includes Employee ID software:

• Each dosimeter reading is specifically and uniquely related to the wearer's identity
  
• Wearer's identity is attached to dosimeter status regardless of work location
  
• Continuity of dosimetry data is maintained
  
• Data can be entered manually or by bar code scanner.

HPRS, Health Physics Record System
The HRPS is an information management system. Based on standard modules, any degree of customisation is possible. HPRS lets you:

• Receive dose data for individuals and groups
  
• Produce radiation dose reports for company or government
  
• Track dosimetry inventory
  
• Maintain updated and historical files for health physics records.
  

GCA (Glow Curve Analyzer)
The Glow Curve Analyzer evaluates a data file of TL glow curves for conformity with a pre-defined standard and specifies the reason for those rejected.

• Reduced visual scanning effort
  
• Detects glow curve shift
  
• Discovers incomplete glow curves
  
• Finds any with too much infra-red tail or non-radiation induced signal.
  

Dose Algorithms
Our validated dose algorithms meet or exceed all applicable laboratory accreditation.

• Report specific dosimeter-reader data in dose equivalent and risk related quantities
  
• Identify constituents of radiation fields and their relative contributions
  
• Establish traceability to Standards.
  

WinREMS
WinREMS -Main Menu
Dose Algorithm

Dosimetry Performance

Radiations measured: Photon, energies > 1 KeV. Neutron, from thermal to 100 MeV. Beta, energies > 70 KeV.
Linear Dose Ranges for nearly tissue equivalent materials:
With LiF:Mg,Ti: 10 µGy (1 mrad) to 10 Gy (1000 rad)
With LiF:Mg,Cu,P: 1 µGy (0.1 mrad) to 20 Gy (2000 rad).
Linearity:
LiF:Mg,Ti <1%, 100 µGy to 1 Gy. LiF:Mg,Cu,P <1%, 10 µGy to 1Gy.
Fading (using total integral): For LiF:Mg,Ti <20% over 3 months without application of thermal treatment or fading correction. <5% over 3 months using our fading correction algorithm, glow curve batch deconvolution or pre-heat. For LiF:Mg,Cu,P fading is negligible.
Batch uniformity: ±30% maximum deviation from the batch mean without application of element correction coefficients.
Residual TL signal:
<0.2% of reading over the total dose range without annealing, for LiF:Mg,Ti
<0.2% of reading over the total dose range without annealing, for LiF:Mg,Cu,P
Repeatability: <2% variation based on one standard deviation for 10 sequential dose measurements at 1 mGy (100 mrad) using ¹³⁷Cs.
Dosimeter reusability: <10% sensitivity change for 500 readouts (50 for EXT-RAD and DXT-RAD).
Minimum detectability: <10 µGy (1 mrad) based on 2.26 standard deviations of 10 repeated evaluations of an unexposed dosimeter. (1 µGy for LiF:Mg,Cu,P).
Annealing: No external annealing is required. The anneal part of the heat cycle can be used to remove residual signal after exposure to a high dose.

Dosimeter Materials

Card Dosimeters Supplied for whole body and environmental monitoring, the precision-machined chips are securely fixed to sturdy aluminum substrates. Holder with filters are supplied in gasket-sealed, polarized, tamper-evident forms with attachment either to belt buckle or lapel.	EXT-RAD Extremity  Monitoring System For monitoring fingers, wrists, ankles etc. Single or double bar coded chipstrate dosimeter elements Sealed pouches attached to the body by extremity straps, finger rings or wristbands Carrier cards, for light readout after exposure, each hold two EXT-RAD dosimeters.
DXT-RAD Extremity Monitoring System Featuring better dosimeter identification, more efficient dosimeter handling and faster processing than others, the DXT-RAD system comprises: A new dosimeter using TL-100/TL-700 chips with permanent circular barcode identifier Sealed, disposable finger rings Ring sealing and chip extraction tools Carrier cards for reading up to four dosimeters.

Models and Options

Model 8800 - Standard version, reads Harshaw TLD whole body, neutron and environmental TLD cards and extremity dosimeters on carrier cards.
Includes: reader, heating system, load and unload cartridges, card transport system, single barcode reader.  TLDREMS and WinREMS software runs on a separate external PC.

Model 8800 Option 1 - as standard model, but includes a triple-head laser barcode scanner for reading EXT-RAD extremity chipstrates.

Model 8800 Option 2 - as standard model, but includes a CCD camera for reading DXT-RAD extremity ringlets, EXT-RAD chipstrates and other standard Harshaw TLD cards.

Irradiator - Optional internal ⁹⁰Sr beta irradiator for automatic card exposures (user defined doses).

Upgrades - Older models M8000C and M8800 can be upgraded in the field by our qualified service engineers, comprising of replacement of the terminal, host computer, transport control, heating station (Option 2 only), power supply, wiring harness, software etc..  One week is required for installation and training.