Ludlum Measurements 4612 User manual

LUDLUM MODEL 4612
12-CHANNEL COUNTER
November 2019

LUDLUM MODEL 4612
12 CHANNEL COUNTER
November 2019
LUDLUM MEASUREMENTS, INC.
501OAK STREET, P.O. BOX 810
SWEETWATER, TEXAS 79556
325-235-5494, FAX:[phone]

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]

DESIGNER AND MANUFACTURER
OF
Scientific and Industrial
Instruments
LUDLUM MEASUREMENTS, INC.
501 OAK ST. / P.O. BOX 810
SWEETWATER, TEXAS 79556
Phone: [phone] (USA)
Fax: [phone] E-Mail: [email protected]m
http://www.ludlums.com
27 October 2017
Model 4612 Counter Addendum
Model 4612AB Update
Beginning with version 2.3.0 of the Model 4612 Counter software, dual channel alpha/beta is supported. This
can be enabled in Tools/Options by checking the Alpha/Beta Configuration.
When enabled, the channel labels are changed from Channel 1-12 to Det 1-6 βand α. Since the alpha detector
board shares the high voltage with its corresponding beta detector board, the high voltage parameters cannot
be adjusted.
The High Voltage Plateau shows in parenthesis the alpha counts when performing a beta plateau and the beta
counts while performing the alpha plateau and automatically calculates the crosstalk percentage.

Table of Contents
INTRODUCTION.............................................................................................................1
SOFTWARE INSTALLATION ........................................................................................4
Connecting a Computer..............................................................................................................................................5
Starting Software.........................................................................................................................................................5
Settings..........................................................................................................................................................................5
General .......................................................................................................................................................................6
Alarm Set Points.........................................................................................................................................................7
Count Time.................................................................................................................................................................8
Plateau........................................................................................................................................................................9
Rate Meter................................................................................................................................................................10
End User License Agreement ...................................................................................................................................11
SOFTWARE FEATURES .............................................................................................14
Counting.....................................................................................................................................................................15
Starting a Count on a Single Channel.......................................................................................................................16
Starting a Count on Multiple Channels (Group Counting).......................................................................................17
Count Data Text Files...............................................................................................................................................18
Channel Colors ..........................................................................................................................................................19
Calibration .................................................................................................................................................................20
High Voltage ............................................................................................................................................................21
Lower Level Discriminator ......................................................................................................................................22
Upper Level Discriminator.......................................................................................................................................23
Efficiency .................................................................................................................................................................24
Mode.........................................................................................................................................................................25
Calibration Wizard....................................................................................................................................................26
HV Actual Calibration Constant...............................................................................................................................26
HV Read Back Calibration Constant........................................................................................................................29
LLD Actual Calibration Constant.............................................................................................................................30
ULD Actual Calibration Constant............................................................................................................................31
HV Plateau .................................................................................................................................................................32
ELECTRONICS SPECIFICATIONS..............................................................................34
DESCRIPTION OF CONTROLS AND FUNCTIONS....................................................35
DRAWINGS AND DIAGRAMS.....................................................................................36

HARDWARE CALIBRATION .......................................................................................50
RS-232 COMMUNICATION..........................................................................................52
RS-232 Commands ....................................................................................................................................................54
Stop Data Output –SOn...........................................................................................................................................54
Read Firmware Version –F .....................................................................................................................................54
Read GM Mode –RGn.............................................................................................................................................54
Set GM Mode –SGnx..............................................................................................................................................54
Read Window Mode –RWn ....................................................................................................................................54
Set Window Mode –SWnx......................................................................................................................................54
Read Efficiency –REn.............................................................................................................................................55
Set Efficiency –SEnxx.............................................................................................................................................55
Save Slave Flash Parameters –SF............................................................................................................................55
Read High Voltage –RHn........................................................................................................................................55
Set High Voltage –SHnxxxx ...................................................................................................................................55
Read High Voltage Actual Cal –RHACn................................................................................................................55
Set High Voltage Actual Cal –SHACnxxx..............................................................................................................55
Read High Voltage Read Back Cal –RHRCn..........................................................................................................55
Set High Voltage Read Back Cal –SHRCnxxx.......................................................................................................55
Read LLD –RLn......................................................................................................................................................56
Set LLD –SLnxxxx .................................................................................................................................................56
Read LLD Actual Cal –RLCnxxx...........................................................................................................................56
Set LLD Actual Cal –SLCnxxx...............................................................................................................................56
Read ULD –RUn.....................................................................................................................................................56
Set ULD –SUnxxxx.................................................................................................................................................56
Read ULD Actual Cal –RUCnxxx ..........................................................................................................................56
Set ULD Actual Cal –SUCnxxx..............................................................................................................................56

Model4612Twelve-ChannelCounter TechnicalManual Section1
Ludlum Measurements, Inc. Page 1 November 2019
Introduction
he Ludlum Model 4612 Counter is a 12-detector SCA (single
channel analyzer) with PC control of all necessary operating
parameters. Up to 12 detectors may be connected to the counter
each with independent high voltage, threshold or sensitivity, and
window settings.
The counter is configured with a host board and up to 12 slave boards. The
host board collects the counts from each slave board and communicates
with the computer. The host board has an RS-232 connector for
communicating with a computer or other device capable of serial
communication, a power connector, and a reset button. The reset button
performs the same function as cycling the power. The slave boards are
responsible for powering the detector and sending the count data to the host
board.
The counter host board recalls all parameters from its built-in flash memory
and configures the slave boards during the power-up sequence. The
parameters include High Voltage, Upper Level Discriminator (ULD), Lower
Level Discriminator (LLD), GM Mode, and Window Mode. Because the
host board sends the parameters over to the slaves during power-up, a slave
board may be replaced while still keeping the same operating parameters as
the previous slave board.
When using GM detectors, the GM Mode should be activated to prevent
double pulsing and longer dead times. The Window Mode determines if the
ULD is enabled. The ULD may be disabled by disabling the Window
Mode.
Typically a computer is used to collect and display the data, send parameters,
and to start and stop counts. The Model 4612 Counter software (supplied)
monitors the activity of the counter. The software allows the user to control
and log data from individual channels or groups of channels. The software
also allows the user to modify the parameters if each slave board.
Section
1
T

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Ludlum Measurements, Inc. Page 2 November 2019
The software receives a data stream every 50 milliseconds from the 4612
counter that contains the total counts for each of the 12 channels for the
previous 50 millisecond period. These counts are displayed in the “Counts
50 mSec” column on the main screen. When a channel is counting, the
accumulated count for each channel is stored in the “Accumulated Count”
column on the main screen. The “Last Count” stores the last completed
count. The Rate Meter column shows the current count rate in a user-
defined unit of measure (cps, cpm, R/hr, Sv/hr). When the user starts
counting on a particular channel (or a group of channels simultaneously), the
software starts accumulating 50 millisecond counts until the count time has
completed.
A count may be started on a single channel or a group of channels. To start
counting on a single channel, click on the “Count” button. The count is
started immediately and when the count is complete, the result is saved to a
file. Clicking on the “Start Counts” button will allow the user to select
which channels to group in this count and select the count time. A group
number is assigned to provide a means to differentiate each count group.
Counts may be set to start again automatically. If the “Recycle” check box is
selected when the “Count” button is clicked, the count will automatically
restart after a count is complete. Once in the recycle mode, the count must
be stopped manually by clicking on the “Cancel” or “Stop All Counts”
button.
After a count is complete, the data is saved to a comma separated value
(.CSV) file suitable for loading into a spreadsheet or database program for
further processing. This serial number, group number, channel, count time,
count, rate meter reading, HV, LLD, ULD, efficiency, and date are saved to
the file. The file name is in the format of YYYYMMDD.CSV where
“YYYY” is the current year, “MM” is the current month, and “DD” is the
current day. A new file is created when the date changes.
In addition to the counting functions, the 4612 counter software also stores
alarm points for each of the 12 channels. If a timed count is running and the
accumulated count value exceeds the alarm set point, the “Accumulated
Count” background will turn red, indicating an alarm condition. The
software also has an optional audible alarm (which can be changed to any
.wav file) to indicate an alarm condition.
The software features an easy to use “Wizard” to calibrate each channel’s
various calibration constants. These constants are: HV Actual Cal, HV Read
Back Cal, LLD Actual Cal, and ULD Actual Cal.
Finally, the 4612 Counter software has a function known as HV Plateau.
This function is used to determine the correct operating voltage (or HV) for

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Ludlum Measurements, Inc. Page 3 November 2019
an individual or group of detectors. The HV Plateau function will take
background counts at different HV intervals (set by the user) for a single
detector or multiple detectors. After the background counts have completed,
the software will take source counts on each detector. When the source
counting is completed on each detector, the net count in counts per minute
(CPM) and the detector efficiency will then be calculated and displayed.
When the plateau is complete, the user has the option to save or print the
plateau results.