Ludlum Measurements 16 User manual

LUDLUM MODEL 16
ANALYZER
July 2011
Serial Number 95362 and Succeeding
Serial Numbers

LUDLUM MODEL 16
ANALYZER
July 2011
Serial Number 95362 and Succeeding
Serial Numbers

STATEMENT OF WARRANTY
Ludlum Measurements, Inc. warrants the products covered in this manual to be free of
defects due to workmanship, material, and design for a period of twelve months from the
date of delivery. The calibration of a product is warranted to be within its specified
accuracy limits at the time of shipment. In the event of instrument failure, notify Ludlum
Measurements to determine if repair, recalibration, or replacement is required.
This warranty excludes the replacement of photomultiplier tubes, G-M and proportional
tubes, and scintillation crystals which are broken due to excessive physical abuse or used
for purposes other than intended.
There are no warranties, express or implied, including without limitation any implied
warranty of merchantability or fitness, which extend beyond the description of the face
there of. If the product does not perform as warranted herein, purchaser’s sole remedy
shall be repair or replacement, at the option of Ludlum Measurements. In no event will
Ludlum Measurements be liable for damages, lost revenue, lost wages, or any other
incidental or consequential damages, arising from the purchase, use, or inability to use
product.
RETURN OF GOODS TO MANUFACTURER
If equipment needs to be returned to Ludlum Measurements, Inc. for repair or calibration, please send to
the address below. All shipments should include documentation containing return shipping address,
customer name, telephone number, description of service requested, and all other necessary information.
Your cooperation will expedite the return of your equipment.
LUDLUM MEASUREMENTS, INC.
ATTN: REPAIR DEPARTMENT
501 OAK STREET
SWEETWATER, TX 79556
800-622-0828 325-235-5494
FAX [phone]

Ludlum Measurements, Inc. July 2011
Table of Contents
Introduction 1
Getting Started 2
Unpacking and Repacking 2-1
Battery Installation 2-1
Connecting a Detector to the Instrument 2-2
Battery Test 2-2
Instrument Test 2-2
Operational Check 2-3
Specifications 3
Identification of Controls and Functions 4
Safety Considerations 5
Environmental Conditions for Normal Use 5-1
Warning Markings and Symbols 5-1
Cleaning and Maintenance Precautions 5-2
Calibration and Maintenance 6
Establishing an Operating Point 6-1
Calibration 6-1
GM Detectors 6-2
Proportional Detectors 6-2
Scintillation Detectors 6-3
Window Calibration 6-3
HV Calibration 6-4
Ratemeter Calibration 6-5
Detector Overload Calibration 6-5
With Scintillation Detectors 6-5
With GM Detectors 6-5
Maintenance 6-6
Recalibration 6-7

Model 16 Analyzer Technical Manual
Ludlum Measurements, Inc. July 2011
Batteries 6-7
Troubleshooting 7
Troubleshooting Electronics which utilize a
GM, Scintillator or Proportional Detector 7-1
Troubleshooting GM Detectors 7-3
Troubleshooting Scintillators 7-4
Troubleshooting Proportional Detectors 7-4
Recycling 8
Parts List 9
Model 16 Analyzer 9-1
Main Board, Drawing 363 × 558 9-1
Calibration Board, Drawing 363 × 511 9-4
Wiring Diagram, Drawing 363 × 515 9-4
Drawings and Diagrams 10

Model 16 Analyzer Technical Manual Section1
Ludlum Measurements, Inc. Page 1-1 July 2011
Introduction
he Ludlum Model 16 Analyzer supplies the complete electronic
requirements for scintillation, proportional, or GM monitoring with
the added feature of a window discriminator circuit.
A two-position switch, marked WIN IN/OUT allows the instrument to
operate as a gross count ratemeter or as a single-channel analyzer. With the
WIN switch in the OUT position, the discriminator level is controlled by the
THR potentiometer, which is adjustable from 2 to 60 mV. In this mode, the
instrument performs as a gross count ratemeter. With the WIN switch in the
IN position, the WIN potentiometer controls the high discriminator level. The
high discriminator level may be adjusted between the THR level and two
times the threshold level (not to exceed 60 mV). Other features include AUD
ON/OFF and fast/slow (F/S) meter response switches, meter RESET and high
voltage (HV) test buttons.
Section
1
T

Model 16 Analyzer Technical Manual Section2
Ludlum Measurements, Inc. Page 2-1 July 2011
Getting Started
Unpacking and Repacking
Remove the calibration certificate and place it in a secure location. Remove
the instrument and accessories (batteries, cable, etc.) and ensure that all of
the items listed on the packing list are in the carton. Check individual item
serial numbers and ensure calibration certificates match. The Model 16 serial
number is located on the front panel below the battery compartment. Most
Ludlum Measurements, Inc. detectors have a label on the base or body of
the detector for model and serial number identification.
Important!
If multiple shipments are received, ensure that the detectors
and instruments are not interchanged. Each instrument is
calibrated to specific detectors, and therefore, not
interchangeable.
To return an instrument for repair or calibration, provide sufficient packing
material to prevent damage during shipment. Also provide appropriate
warning labels to ensure careful handling. Include detector(s) and related
cable(s) for calibration. Include brief information as to the reason for return,
as well as return shipping instructions:
- Return shipping address
- Customer name or contact
- Telephone number
- Description of service requested and all other necessary
information
Battery Installation
Ensure the Model 16 range selector switch is in the OFF position. Open the
battery lid by pushing down and turning the quarter-turn thumbscrew
Section
2

Model 16 Analyzer Technical Manual Section2
Ludlum Measurements, Inc. Page 2-2 July 2011
counterclockwise a quarter of a turn. Install two ˝D˝size batteries in the
compartment.
Note the (+) and (-) marks inside the battery door. Match the battery
polarity to these marks. Close the battery box lid, push down, and turn the
quarter-turn thumb screw clockwise a quarter of a turn.
Note:
Center post of a flashlight battery is positive. The batteries are
placed in the battery compartment in opposite directions.
Connecting a Detector to the Instrument
Caution!
The detector operating voltage (HV) is supplied to the detector
via the detector input connector. A mild electric shock may
occur if you make contact with the center pin of the input
connector. Switch the Model 16 range selector switch to the
OFF position before connecting or disconnecting the cable or
detector.
Connect one end of a detector cable to the detector by firmly pushing the
connectors together while twisting clockwise a quarter of a turn. Repeat the
process in the same manner with the other end of the cable and the
instrument.
BatteryTest
The batteries should be checked each time the instrument is turned on.
Move the range switch to the BAT position. Ensure that the meter needle
deflects to the battery check portion on the meter scale. If the meter does
not respond, check to see if the batteries have been correctly installed.
Replace the batteries if necessary.
Instrument Test
After checking the batteries, turn the instrument range switch to the ×1000
position. Place the AUD ON-OFF switch in the ON position and the WIN
IN/OUT switch to the OUT position. Expose the detector to a check source.

Model 16 Analyzer Technical Manual Section2
Ludlum Measurements, Inc. Page 2-3 July 2011
The instrument speaker should emit ˝clicks˝ relative to the rate of counts
detected. The AUD ON/OFF switch will silence the audible clicks if in the OFF
position. It is recommended that the AUD ON/OFF switch be kept in the OFF
position when not needed in order to preserve battery life.
Rotate the range switch through the lower scales until a meter reading is
indicated. While observing the meter fluctuations, select between the fast
and slow response time (˝F/S˝) positions to observe variations in the display.
The ˝S˝position should respond approximately 5 times slower than the ˝F˝
position.
Note:
The slow response position is normally used when the
instrument is displaying low numbers, which require a more
stable meter movement. The fast response position is used at
high rate levels.
Check the meter reset function by depressing the RES pushbutton and
ensuring the meter needle drops to “0.” When the RES pushbutton is
released the meter needle recovers to the original reading.
Depress the HV pushbutton and note that the meter indicates the high-
voltage set point.
Note:
HV power supply has an output impedance of 5.7 megohms.
HV load should not exceed 25 µA. Calculate the scintillation
detector loading if an exact high-voltage setting is required.
See calibration procedures for details on the WIN IN/OUT operation.
Once this procedure has been completed, the instrument is ready for use.
Operational Check
To assure proper operation of the instrument between calibrations and
periods of nonuse, an instrument operational check including battery test
and instrument test (as described above) should be performed prior to use.