Ludlum Measurements 43-147 User manual

LUDLUM MODEL 43-147
ALPHA/BETA DETECTOR
March 2019

LUDLUM MODEL 43-147
ALPHA/BETA DETECTOR
March 2019

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. August 2015
Table of Contents
Introduction 1
Specifications 2
Safety Considerations 3
Environmental Conditions for Normal Use 3-1
Cleaning Instructions and Precautions 3-1
Returning for Repair or Calibration 3-1
Parts List 4
Model 43-147 Assembly, Drawing 393 x 288A 4-1
1/8-inch Voltage Divider Board, Drawing 435 x 1700 4-2
Drawings and Diagrams 5

Models43-147 TechnicalManual Section1
Ludlum Measurements, Inc. Page 1-1 March 2019
Introduction
he Model 43-147 detector is designed for alpha-beta surveying when
coupled with compatible instruments. Functionally, these two
detectors are very similar but differ in the type of protective window
screen and the size of the active and open window areas.
Discriminating between alpha and beta radiation simultaneously requires the
counting instrument to have either separate power supplies or
window/threshold controls for each channel. The Ludlum Model 2929 Scaler,
Model 2223, Model 2224, or Model 2360 instruments provide the necessary
circuitry for simultaneous alpha-beta discrimination.
A Zinc Sulfide [ZnS (Ag)] scintillator is used for detecting alpha particles, and a
thin plastic scintillator is employed for detecting beta radiation. The scintillation
material is covered by metallized polyester to reduce light response, limiting
excessive background counts. The Model 43-147 window is protected by an
88% open square-hole screen.
The photomultiplier tube (PMT) and crystal assembly may easily be removed
for repair. Refer to the assembly view drawing in section 5 of this manual for
details on construction and parts. The photomultiplier tube typically operates
between 500 and 1200 volts with a recommended maximum of 1500 volts.
Section
1
T

Models43-147 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-1 March 2019
Specifications
0
Photomultiplier Tube:2.9 cm (1.1 in.) diameter; magnetically shielded
Scintillator Material: Zinc Sulfide [ZnS (Ag)] deposited on a 0.25 mm
(0.010 in.) rectangular plastic scintillator
Removable Protective Screen: 0.79 mm (0.03 in.) thick, 6.5 mm (0.26
in.) square openings, 88% open
Screen Outer Dimensions: 225.4 x 113.7 mm (8.875 x 4.75 in.) (L x W)
Window: 1.2 mg/cm2metalized polyetser
Window Area:
Active area:approximately 200 cm2
Open area:approximately 176 cm2
Efficiency (4): typically 13% for 99Tc, 20% for 90Sr 90Y, and 20% for
239Pu
Background (in a 10µR/hr field):
Alpha: 3 cpm or less
Beta: 400 cpm or less
Cross Talk:
Alpha to Beta: < 10%
Beta to Alpha: < 1%
Response Uniformity: 10% or less from average reading
Operating Voltage: typically 500-1200 Vdc (1500 Vdc max.)
Section
2

Models43-147 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-2 March 2019
Dynode String Resistance:60 megohm
Gamma Sensitivity: 15-20 cpm/µR/hr (137Cs)
Dead Time: typically 5 µsec or less
Connector: Series “C” unless otherwise specified
Temperature Range:-20 to 50 °C (-4 to 122 °F)
Overall Size: 10.7 x 12.1 x 35.6 cm (4.2 x 4.75 x 14 in.) (H x W x L),
plus feet
Weight: 0.7 kg (1.0 lb)
Construction: aluminum housing with beige powder-coat finish

Models43-147 TechnicalManual Section3
Ludlum Measurements, Inc. Page 3-1 March 2019
Safety Considerations
Environmental Conditions for Normal Use
Indoor or outdoor use
No maximum altitude
Temperature range of -20 to 50°C (-4 to 122 °F)
Maximum relative humidity of less than 95% (non-condensing)
Cleaning Instructions and Precautions
The detectors specified in this manual may be cleaned externally with a
damp cloth, using only water as the wetting agent. Do not immerse the
detector in any liquid. Do not attempt to clean a detector that is attached to
an instrument providing high voltage. Disconnect the detector cable before
cleaning.
Returning for Repair or Calibration
To return an instrument for repair or calibration, provide sufficient packing
material to prevent damage during shipment.
Every returned instrument must be accompanied by an Instrument Return
Form, which can be downloaded from the Ludlum website at
www.ludlums.com. Find the form by clicking the “Support” tab and
selecting “Repair and Calibration” from the drop-down menu. Then choose
the appropriate Repair and Calibration division where you will find a link to
the form.
Section
3

Models43-147 TechnicalManual Section4
Ludlum Measurements, Inc. Page 4-1 March 2019
Parts List
Reference Description Part Number
UNIT Completely Assembled
Model 43-147
200 cm2Alpha /Beta Scintillator 47-4092
Quantity Description Part Number
1 ea Welded Body Assembly 2393-289
1 ea Mirror 7393-297
1 ea Connector Cap 7393-102
1 ea Mylar Window Assembly 4393-299
1 ea Window Frame 7393-295
1 ea Face Ring 7393-291
1 ea Square Screen
(external snap-on screen) 7393-292
1 ea Backup w/Plastic Scintillator
and ZnS 4393-300
1 ea Plastic Scintillator-
EJ444L-2.94 x5.91x 0.010 7393-294
1 ea Photomultiplier Tube 01-5238
1 ea Voltage Divider Board 5435-182
* Foil-NETIC 01-5019
* Foil-CO-NETIC 01-5026
9 ea Sponge 7002-065-04
1 ea Tube Holder Assembly 2393-117
1 ea Gasket 7393-296
1 ea O-Ring 16-8366
1 ea Series "C" Connector
RECPT-UG706/U 4478-011
1 ea M 43-93 Vinyl Cover 7393-162
Section
4
For Model 43-147
Assembly View,
Drawing 393 x 288

Models43-147 TechnicalManual Section4
Ludlum Measurements, Inc. Page 4-2 March 2019
Reference Description Part Number
BOARD Completely Assembled 1 1/8 inch
Voltage Divider Board 5435-533
C1- C3 0.01uF, 200V 04-5725
C4 0.0047uF, 3KV 04-5958
R1 10M, 1/8W, 1% 12-7996
R2 7.5M, 1/8W, 5% 12-7971
R3-R10 10M, 1/8W, 1% 12-7996
R11 2.21M, 1/8W, 1% 12-7002
R12-R13 6.04M, 1/8W, 1% 12-7071
* SOCKET 1 1/8” PCB MOUNT 4435-103
W1 SILICONE WHITE #22 HV 21-8543
W4 SILICONE BLACK #22 GND 21-8552
1 1/8-inch Voltage
Divider Board,
Drawing 435 × 1700
CAPACITORS
RESISTORS
MISCELLANEOUS