Fluke 943-27 Detector User Manual

Victoreen

Current Mode Beta Scintillation Detector,

Model 943-27

Operator Manual

Fluke Biomedical

Radiation Management Services

6045 Cochran Road Cleveland, Ohio 44139

440.498.2564

www.flukebiomedical.com/rms

Table of Contents

Section 1: General Information............................................................................................................. 1-1

1.1 General Description ............................................................................................................... 1-1

1.2 Application.............................................................................................................................. 1-1

1.3 Specifications......................................................................................................................... 1-2

1.4 Auxiliary Equipment...............................................................................................................1-3

1.5 Recommend Spare Parts.......................................................................................................1-3

1.6 Receiving Inspection.............................................................................................................. 1-3

1.7 Storage................................................................................................................................... 1-4

Section 2: Theory of Operation............................................................................................................. 2-1

2.1 Functional Description ........................................................................................................... 2-1

2.2 Theory of Operation............................................................................................................... 2-1

Section 3: Operation..............................................................................................................................3-1

3.1 Installation.............................................................................................................................. 3-1

3.2 Set-Up.................................................................................................................................... 3-3

3.3 Operation ............................................................................................................................... 3-4

Section 4: Maintenance, Calibration and Troubleshooting ............................................................... 4-1

4.1 Maintenance........................................................................................................................... 4-1

4.2 Calibration.............................................................................................................................. 4-1

4.3 Troubleshooting ..................................................................................................................... 4-9

Appendix A: Connector Designations .....................................................................................................A-1

A.1 Connector Designations.........................................................................................................A-1

Appendix B: Applicable Drawings............................................................................................................B-1

B.1 Applicable Drawings...............................................................................................................B-1

Appendix C: Bill of Materials.....................................................................................................................C-1

C.1 Bill of Materials.......................................................................................................................C-1

Appendix D: Cable Termination Instructions..........................................................................................D-1

D.1 Cable Termination Instructions..............................................................................................D-1

Appendix E: Modification Sheets/Engineering Instructions .................................................................E-1

E.1 Modification Sheets/Engineering Instructions........................................................................E-1

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General Information

General Description

Section 1

General Information

1.1 General Description

The Victoreen® Model 943-27 Current Mode Beta Scintillation detector is a radiation detection device that detects beta radiation. The detector is housed in a 1.5-inch diameter stainless steel tube. The detector is identified as the Model 943-27 and is manufactured as a P/N 943-27-31 detector assembly. Both identification numbers are used interchangeably throughout this manual. The detector is designed for accident range operation.

The detector operates at a potential of approximately (-) 500 VDC and provides a nominal DC output current of 1 x 10 The detector consists of a 0.002-inch thick Titanium end window, a calcium fluoride scintillation crystal optically coupled to a quartz light pipe and a photomultiplier tube.

The detector is designed to operate with a Model 943-227-15 Series Digital preamplifier and a Model 960 Digital Process Radiation monitoring system or a Model 942A-200C Series Digital Ratemeter. The Model 943-227-15 Digital Preamplifier is a self-contained electrometer housed in a NEMA 4 enclosure. The preamplifier processes the DC input signal, digitizes the signal, and then transmits the digitized radiation value to the readout device via a RC232C compatible serial data communication. For additional information on the preamplifier and readout device, refer to the applicable product or system level instruction manual.

Interconnection between the detector and preamplifier is accomplished using two (2) six (6) foot coaxial cables. One cable supplies the detector high voltage and the other cable provides the signal output

For additional information on the detector preamplifier or readout device, refer to the instruction manual for the Model 943-227-15 Preamplifier, the Model 942A-200C UDR, or the applicable Model 960 System manual.

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amperes at 1 x 10-3 to 1 x 10-5 uCi/cc. The maximum current output is 1 x 10-4 amperes.

1.2 Application

The Model 943-27-31 Detector is used with the Victoreen 942A-200C or Model 960 Digital Process Radiation monitor and the Model 943-227-15 Series Digital preamplifier. The Model 942A-200C or 960 system readouts provide the +15 VDC preamplifier electronics power, (-) 500 VDC detector power and the RS232C serial communications support. The digital preamplifier converts the detector output into a digital signal for processing by the digital readout. Table 1-1 is a list of available configurations and compatible 9XX series equipment. Please contact Fluke Biomedical Radiation Management Services for additional information.

Table 1-1 943-27 Variations and Compatible Equipm ent

Detector Preamplifier

Variations

943-27-31 Beta Detector, Current Mode Operation

943-227-15 Digital Preamplifier

943-227-15VL Digital Preamplifier

Application Readout

Transmission Distances Less than 50 feet

Transmission Distances up to 1 mile

942A-200C Digital Ratemeter or Model 960 Digital Process Control System

1-1

943-27 Beta Scintillation Detector

Operator Manual

1.3 Specifications

General specifications for the Model 943-27 Detector are listed below. The 943-27 series products are designed for nuclear applications, and any repairs to it by personnel not qualified to ANSI 45.2.6 1978, Skill Level II may void the nuclear rating.

If a problem develops, the preamplifier may either be returned to the factory for service, or repaired by a qualified technician.

Table 1-2. General Specifications for the 943-27 Detector

Feature: Specification: Radiation Detected

End Window

Scintillation Crystal

Detector Housing Detector Constant

Detector Range Energy Dependence

and Efficiency Power Requirements

Operating Temperature Relative Humidity Operating Pressure Dimensions Weight

Preamplifier Interface

Modification Information

Beta rays Titanium, 1.125 in dia. x 0.0002 in thick, designed to maximize beta

transmission and minimize noble gas adsorption Calcium Fluoride, CaF

(Eu)

1.125 in dia. X 0.005 in thick interfaced to 1.125 in dia. x 0.125 in thick quartz light pipe

Stainless Steel

1.0 x 10 sampling geometry

1.0 x 10

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uCi/cc/picoampere, typical, based on calibration method and

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to 1.0 x 10-4 amperes (approximately 1.0 x 10-3 to 1.0 x 105 uCi/cc, based on calibration method and sampling geometry Dependent on sampling geometry; Refer to Appendix C for applicable isotopic calibration reports

(-) 500 VDC @ 400 uAmperes 0° F to 122 °F (-16 °C to 50 °C) 0 – 95 %, non-condensing 12 psig max

1.5 in dia. x 9.0 in long (3.8 cm x 22.9 cm) 3 lbs (1.4 kg)

High Voltage: Six (6) foot coaxial cable with pre-terminated SHV connector and “Seal Grip”; Signal: Six (6) foot coaxial cable with pre-terminated BNC connector and “Seal Grip”;

None

1-2

General Information

Inspection & Storage

1.4 Auxiliary Equipment

Model

None See Table 1-1 for compatible equipment

Description

1.5 Recommended Spare Parts

Table 1-9 Recommended Spare Parts List for the Model 943-27 Detector

Part Number Description Used On

There are no replaceable parts in the 943-27 detector

1.6 Receiving Inspection

Upon receipt of the unit:

1. Inspect the carton(s) and contents for damage. If damage is evident, file a claim with the carrier and notify the Fluke Biomedical Radiation Management Services Customer Service Department.

Fluke Biomedical

Radiation Management Service

6045 Cochran Road

Cleveland, Ohio 44139

Phone: 440.248.9300

Fax: 440.542.3682

2. Remove the contents from the packing material.

3. Verify that all items listed on the packing list have been received and are in good condition.

NOTE

Management Service Customer Service Department If any of the listed items are missing or damaged, notify the Fluke Biomedical Radiation

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943-27 Beta Scintillation Detector

Operator Manual

1.7 Storage

Storage of Fluke Biomedical instruments must comply with Level B storage requirements as outlined in ANSI N45.2.2 (1972) Section 6.1.2(.2). The storage area shall comply with ANSI N45.2.2 (1972) Section

6.2 Storage Area, Paragraphs 6.2.1 through 6.2.5. Housekeeping shall conform to ANSI N45.2.3 (1972). Level B components shall be stored within a fire resistant, tear resistant, weather tight enclosure, in a

well-ventilated building or equivalent. Storage of Fluke Biomedical instruments must comply with the following:

1. Inspection and examination of items in storage must be in accordance with ANSI N45.2.2 (1972) Section 6.4.1.

2. Requirements for proper storage must be documented and written procedures or instructions must be established.

3. In the event of fire, post-fire evaluation must be in accordance with ANSI N45.2.2 (1972), Section

6.4.3.

4. Removal of items from storage must be in accordance with ANSI N45.2.2 (1972), Sections 6.5 and

6.6.

1-4

Theory of Operation

Functional Description

Section 2

Theory of Operation

2.1 Functional Description

The detector is comprised of a thin calcium fluoride scintillation disc located behind an ultra-thin (0.0002 in) Titanium end window. The end window permits the penetration of Beta rays as low as 80 Kev. The calcium fluoride disc is optically coupled to the active cathode of a one-inch diameter photomultiplier tube (PMT). A schematic representation of the detector is shown on drawing 943-27-32, located in Appendix A. As shown in the schematic, the cathode of the PMT is tied to a negative high voltage through a ten (10) megohm current limiting resistor, R1. The PMT dynodes are biased by the divider string formed by resistors R2 through R13. The output signal is taken directly from the PMT anode, which is held at a virtual ground potential by the input of the associated integrating electrometer.

2.2 Theory of Operation

Beta particles that have enough energy to penetrate the end window and impinge upon the disc will produce light pulses, proportional to the energy deposited in the disc. The disc is thin so that gamma rays will not have a high incidence of interaction with the disc. This yields a high rejection of gamma rays while still possessing good sensitivity to beta particles.

A photomultiplier tube, optically coupled to the scintillation disc, detects visible light emitted from the disc and converts this light to electrical energy that is proportional to the energy deposited by the beta particle. The electrical charge is sent to an electrometer in an external preamplifier that converts the charge into a digital value for display and processing.

2-1

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Operation

Installation

Section 3

Operation

3.1 Installation

Installation consists of mounting the detector in its associated sampling geometry and making the required electrical connections. Refer to the applicable sampling geometry in struction manual for detector installation instructions.

CAUTION

Remove all power prior to installing the Detector.

Detector Mounting

The detector is designed to be installed within a sampling geometry. The detector is normally part of the process pressure boundary, and is normally installed using to mounting flanges and 2 quad-lobed seal orings. The basic mounting procedure is provided below. Refer to the specific sampling geometry installation procedure for further information.

The following materials are normally needed to remove or install the Model 943-27 detector:

O-Ring Lubricant, Dow Corning #55, or equivalent 1ea, 3/16 Hex head bit or T-handle tool

1ea, P/N 943-27-47, Detector Mounting Flange 1ea, P/N 46-103, Quad lobed seal (Detector mounting flange to Adapter flange) 6ea, P/N 5-610, 10-32 x 0.62 Socket head cap screws (varies with application) 6ea, P/N 5-795, #10 split washes, Stn Stl (varies with application)

1ea, P/N 943-27-48, Adaptor Flange 1ea, P/N 46-104, Quad lobed seal (Adapter flange to sampler body) 6ea, P/N 5-1080, 10-32 x 0.88 Socket head cap screws (varies with application) 6ea, P/N 5-795, #10 split washes, Stn Stl (varies with application) 6ea, P/N 5-795, #10 flat washers, Stn Stl (varies with application)

CAUTION

Due to the potential for high activity radioactive gasses in or around the vicinity of the detector, protective Clothing should be worn while installing or removing the detector

Detector Installation

Detector installation includes installing the adaptor flange and quad-lobed seal o-ring, installing the detector mounting flange, detector flange quad-lobed seal o-ring, inserting the detector into the detector mounting tube and securing the detector mounting flange. The high voltage power supply for the detector, if operational, must be turned off by turning the controlling Digital Ratemeter or 960 System power OFF.

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Fluke 943-27 Detector User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual