TSA PRM-470B Manuale di servizio
PORTAL RADIATION MONITOR
MODEL PRM-470B
OPERATING AND SERVICE MANUAL
Version 1.01z
December 20, 2004
PRM-470B
TABLE OF CONTENTS
1. INTRODUCTION.....................................................................................................................1
1.1. SCOPE AND PURPOSE OF MANUAL....................................................................1
1.2. GENERAL DESCRIPTION.......................................................................................1
1.3. SAFETY PRECAUTIONS.........................................................................................3
1.4. SPECIFICATIONS.....................................................................................................4
2. INSPECTION AND SETUP ....................................................................................................6
2.1. INSPECTION..............................................................................................................6
2.2. SET-UP PROCEDURES ............................................................................................7
2.3. INITIAL SETUP CHECKLIST..................................................................................9
3. OPERATING INSTRUCTIONS...........................................................................................10
3.1. POWER-UP AND SELF TEST................................................................................10
3.2. SEARCH MODE ......................................................................................................11
3.3. BACKGROUND MODE..........................................................................................11
3.4. MODE CHANGE AND RESET...............................................................................12
3.5. DISPLAY BACKLIGHT..........................................................................................12
3.6. LOW BATTERY DETECT......................................................................................12
3.7. RECOMMENDED SETTINGS................................................................................13
3.8. TYPICAL SEARCH PROCEDURES......................................................................13
4. THEORY OF OPERATION..................................................................................................15
4.1. COMPONENTS AND SUBASSEMBLIES.............................................................15
4.2. SELF TEST (SYSTEM RAM) .................................................................................16
4.3. BACKGROUND MODE..........................................................................................17
4.4. SEARCH MODE ......................................................................................................17
4.5. AUDIO ALARM.......................................................................................................18
5. MAINTENANCE....................................................................................................................19
5.1. MAINTENANCE PROCEDURES ..........................................................................19
5.2. ELECTRONIC CALIBRATION PROCEDURE.....................................................19
5.3. TUNE-UP AND CALIBRATION CHECKLIST.....................................................21
6. TROUBLESHOOTING .........................................................................................................22
6.1. COMPONENT ACCESS..........................................................................................22
6.2. TROUBLESHOOTING GUIDE ..............................................................................25
6.3. PRCB-001 BOARD ..................................................................................................28
APPENDIX..................................................................................................................................29
A. WARRANTY..........................................................................................................................29
B. GLOSSARY............................................................................................................................30
C. FORMULAS...........................................................................................................................32
C.1. ACTIVITY FROM COUNTS..................................................................................32
C.2. EFFICIENCY...........................................................................................................32
C.3. N*SIGMA ALARM LEVEL ...................................................................................32
C.4. RELIABLE DETECTABLE ACTIVITY (RDA) FORMULA................................33
C.5. SIGNAL TO BACKGROUND RATIO...................................................................33
C.6. VARIANCE..............................................................................................................34
D. CONFIGURATION TRACKING SHEET..........................................................................35
E. PARTS.....................................................................................................................................36
E.1. RECOMMENDED SPARE PARTS.........................................................................36
E.2. SPARE PARTS ORDERING INFORMATION......................................................37
F. DRAWINGS............................................................................................................................38
1. INTRODUCTION page 1
Model PRM-470B
1. INTRODUCTION
1.1. SCOPE AND PURPOSE OF MANUAL
This manual is designed to enable operating and service personnel to properly operate and care
for the PRM 470B. Since applications are necessarily site-specific, operation procedures are
given in general terms. Service and repair are covered to the board or assembly level. Anything
more complex than this requires that the instrument or assembly be returned to TSA.
1.2. GENERAL DESCRIPTION
The TSA Model PRM-470B Portable Radiation Monitor is a light-weight, portable, hand- held
instrument designed to detect radioactive materials. The standard detector is a large plastic
scintillator that is both gamma and neutron sensitive. A display backlight is supplied to permit
use in low light conditions.
Uses for the PRM include Special Nuclear Material (SNM) searches at plant exits and material
access areas, as well as contamination and background monitoring. The small size and light
weight make it ideal for extended search time applications.
Upon power-up, the instrument goes through a self-test and warm-up period followed by an
initial ten second background count. In background mode it continues to update background
counts at ten second intervals; the display flashes the current background. In search mode, the
current background is stored and the instrument makes alarm comparisons every 50
milliseconds. The display will show counts per second, divided by 1000, updated every second.
If the detected radiation level exceeds the pre-programmed alarm level, an audio alarm is
sounded.
1. INTRODUCTION page 2
Model PRM-470B
The instruments covered by this manual have been modified to operate on a set of four AA size,
alkaline batteries. The instrument will operate for approximately 24 hours on a fresh set of
batteries.
The PRM-470B operates in two modes:
• Search mode - to locate radioactive material
• Background mode – to measure radiation intensity
Two rotary switches control sensitivity while in the search mode. The switches are located on
the PRCB-474 PC board inside the instrument. The range of the sensitivity adjustment is 0.1 to
10.0 sigma.
There are two options for displaying the data:
• cps
• µsieverts
There are two rotary dip-switches located on the PRCB-001 board that control the display mode.
If both switches are set to "0", the display is in cps.
NOTE:
The µsievert conversion is not compensated for energy. It is strictly a linear conversion of
counts per µsievert.
1. INTRODUCTION page 3
Model PRM-470B
1.3. SAFETY PRECAUTIONS
Cautions and warnings related to specific procedures are cited at appropriate places in this
manual. A summary is given here.
WARNINGS:
Since the PRM-470B uses high voltage during operation, care must be taken during service
procedures. Service should be done only by qualified personnel.
The electroluminescent backlight utilizes 400 volts ac for operation, and care must be taken to
avoid accidental contact while servicing the instrument.
CAUTIONS:
The PRM-470B is water resistant, but will not withstand immersion in water.
The instrument should not be overcharged, as this will shorten the battery life. The instrument
should not be constantly shallow charged refer to Maintenance Procedures (section 5.1.).
As with any sensitive electronic instrument, the PRM-470B should not be dropped or subjected
to severe mechanical shock.
Damage to the copper coating inside the instrument can result in unacceptable RFI levels.
1. INTRODUCTION page 4
Model PRM-470B
1.4. SPECIFICATIONS
Sensitivity: Will detect 10g HEU or 1g 239Pu
when tested in accordance with ASTM Standard C 1237-93
Detector: One, 3.5"h x 2.88"w x 1.25"d (8.8 x 7.2 x 3.1cm)
plastic scintillator detector; provides 12.6 in3(206 cc) of detector volume
Alarm Levels: Set by two internal rotary switches from 0.1 to 9.9 sigma
Alarm Indication: Audible tone and LED
Count Time: Search mode: 0.05 sec. count with .4 sec. moving average.
Background time: 10 sec.
Display: LCD, one line x 4 characters, with backlight
Power: The internal NiCad battery pack provides more than 60 hours of
continuous operation on a full charge.
Battery Charger: The instrument is shipped with a universal input battery charger which
operates on 90 – 250 Vac, 47 – 63 Hz.
Recharge time is less than 16 hours.
Optional 4 "AA" alkaline batteries will provide more than 24 hours
of operation.
Conversion: µsievert conversion: set by two internal rotary dip-switches;
Range: 100 to 9900 cps/µsievert
1. INTRODUCTION page 5
Model PRM-470B
Dimensions: 8"h x 5"w x 3"d (20 x 12.5 x 7.5cm)
Weight: 2.4 lb (1.1kg) with batteries
Environmental:
Temperature: 32˚ to 100˚F (0˚ to 38˚C)
Humidity: Up to 95% non-condensing
2. INSPECTION AND SET-UP page 6
Model PRM-470B
2. INSPECTION AND SETUP
The following procedures should allow on-site personnel to correctly inspect and set up the
PRM-470B for normal operation. Follow the procedures in the order given. It is recommended
that a copy of the Initial Set-Up Checklist (section 2.3.) be filled out after initial installation and
whenever the PRM-470B is put into service after prolonged storage.
If necessary, consult TSA Systems for assistance in case of unusual site conditions or special
requirements.
2.1. INSPECTION
2.1.1. Incoming Inspection:
Immediately inspect the instrument for mechanical damage, scratches, dents or other defects. It
should be examined for evidence of concealed, as well as external damage.
2.1.2. Damage Claims:
If the instrument is damaged in transit or fails to meet specifications upon receipt, notify the
carrier and TSA Systems immediately. Shipping cartons, packing materials, waybills and other
such documentation should be preserved for the carrier’s inspection. TSA will assist in
providing replacement or repair of the instrument if necessary.
2.1.3. Storage:
If the instrument is to be stored for any length of time, first disconnect power to the instrument
and remove and store any batteries separately in a cool place. If batteries are to be stored for
any length of time, they should be inspected and charged if necessary at least once a month.
Care should always be taken to avoid subjecting the instrument to severe mechanical or
environmental shock. The instrument should be stored in a dry, temperature constant location.
2. INSPECTION AND SET-UP page 7
Model PRM-470B
2.1.4. Shipping:
Before returning the instrument for any reason, notify TSA Systems of the difficulty
encountered, giving the model and serial numbers of the equipment. TSA will furnish specific
shipping instructions.
2.2. SET-UP PROCEDURES
An Initial Setup Checklist is included at the end of this section (section 2.3.). It is recommended
that a copy of this be filled out when the PRM-470B is first set-up, and whenever it is put into
service after prolonged storage.
After initial inspection, charge the battery for several hours. Although the battery is fully
charged before the instrument leaves the factory, some discharge is possible if the instrument has
been in storage for any length of time.
After charging, turn the instrument on and test the controls, display and alarm According to the
steps outlined in Power-Up and Self-Test (section 3.1.) in this manual. While the instrument
comes from the factory tuned and calibrated, the calibration should be verified before putting the
instrument into service.
2.2.1. Alarm Level:
To set the sigma level, open the instrument. Refer to Component Access (section 6.1.) and use a
small slotted screwdriver to turn the two rotary switches marked "sigma" to the desired setting.
Indice
