LUDLUM MODEL 43-93 AND MODEL 43-93-2
ALPHA/BETA SCINTILLATO RS
March 2016
LUDLUM MODEL 43-93 AND MODEL 43-93-2
ALPHA/BETA SCINTILLATO RS
March 2016
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
product
.
use
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.
ATTN: REPAIR DEPARTMENT
501 OAK STREET
SWEETWATER, TX 79556
LUDLUM MEASUREMENTS, INC.
800-622-0828 325-235-5494
FAX 325-235-4672
Table of Contents
Introduction 1
Specifications 2
Safety Considerations 3
Environmental Conditions for Normal Use 3-1
Cleaning Instructions and Precautions 3-1
Parts List 4
Parts for Model 43-93 4-1
Parts for Model 43-93-2 4-2
Parts Common to Both Models 4-2
Drawings and Diagrams 5
Ludlum Measurements, Inc. March 2016
Models 43-93 & 43-93-2 Technical Manual Section 1
Section
1
Introduction
he Model 43-93 and 43-93-2 detectors are designed for alpha-beta
surveying when coupled with compatible instruments. Functionally,
T
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 Mylar to reduce light response, limiting
excessive background counts. The Model 43-93 window is protected by an
88% open square-hole screen, where the Model 43-93-2 window is protected
by a 79% open hexagonal-hole screen.
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.
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.
Ludlum Measurements, Inc. Page 1-1 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 2
Section
2
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
Window: 1.2 mg/cm
Window Area (Model 43-93):
Active area
Open area: approximately 88 cm
2
metalized polyester
: approximately 100 cm2
2
Window Area (Model 43-93-2):
Active area
Open area: approximately 100 cm
Efficiency (4):
Model 43-93: typically 15% for
20% for
Model 43-93-2: typically 10% for
15% for
Background (in a 10µR/hr field):
Response Uniformity: 10% or less from average reading
Operating Voltage: typically 500-1200 Vdc (1500 Vdc max.)
: approximately 126 cm2
239
Pu
239
Pu
Alpha: 3 cpm or less
Beta: 300 cpm or less
2
99
Tc, 20% for 90Sr 90Y, and
99
Tc, 17% for 90Sr 90Y, and
Ludlum Measurements, Inc. Page 2-1 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 2
Dynode String Resistance: 60 megohm
Gamma Sensitivity: 15-20 cpm/µR/hr (
Dead Time
Connector: Series “C” unless otherwise specified
Temperature Range: -20 to 50 °C (-4 to 122 °F)
Size: 6.4 x 9.5 x 31 cm (2.5 x 3.8 x 12.3 in.) (H x W x L)
Weight: approximately 0.45 kg (1 lb)
Construction: aluminum housing with beige powder-coat finish
: typically 5 µsec or less
137
Cs)
Ludlum Measurements, Inc. Page 2-2 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 3
Section
3
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.
Ludlum Measurements, Inc. Page 3-1 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 4
Section
4
For Model 43-93
Assembly View,
Drawing 393 × 140
Parts List
Reference Description Part Number
UNIT Completely Assembled
Model 43-93
Alpha /Beta Scintillator 47-3475
Quantity Description Part Number
1 ea Welded Body Assembly 2393-141
1 ea Mirror 2310698
1 ea Connector Cap 7393-102
1 ea Mylar Window Assembly 4393-149
1 ea Window Frame 7393-148
1 ea Face Ring 7393-137
1 ea Square Screen
(external snap-on screen) 7393-171
1 ea Backup w/Plastic Scintillator
and ZnS 4393-153
1 ea Plastic Scintillator EJ444L-2.94 x5.91x 0.010 01-5692
1 ea Photomultiplier Tube 01-5842
1 ea Voltage Divider Board 5435-484
* 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 7393-139
1 ea O-Ring 16-8366
1 ea Series "C" Connector
RECPT-UG706/U 4478-011
1 ea Model 43-93 Vinyl Cover 7393-162
Ludlum Measurements, Inc. Page 4-1 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 4
Reference Description Part Number
For Model 43-93-2
Assembly View,
Drawing 393 × 119
Parts Common to
both Model 43-93
and 43-93-2
1 1/8-inch Voltage
Divider Board,
Drawing 435 × 1325
CAPACITORS
RESISTORS
UNIT Completely Assembled
Model 43-93-2
Alpha /Beta Scintillator 47-3227
Quantity Description Part Number
1 ea Welded Body Assembly 2393-105
1 ea Mirror 2310654
1 ea Connector Cap 7393-102
1 ea Mylar Window Assembly 4393-126
1 ea Window Frame 7393-109
1 ea Face Ring 7393-112
1 ea Hex Screen
(external snap-on screen) 7393-116
1 ea Backup w/Plastic Scintillator
and ZnS 4393-127
1 ea Plastic Scintillator EJ212-3.12 x 6.67 x 0.010 01-5685
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 7393-110
1 ea O-Ring 16-8366
1 ea Series "C" Connector
RECPT-UG706/U 4478-011
1 ea Model 43-93-2 Vinyl Cover 7393-169
Reference Description Part Number
BOARD Completely Assembled 1 1/8 inch
Voltage Divider Board
(Models 43-93 & 43-93-2) 5435-484
C1- C3 0.01uF, 200V 04-5725
C4 0.0047uF, 3KV 04-5547
R1 10M, 1/8W, 1% 12-7996
Ludlum Measurements, Inc. Page 4-2 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 4
Reference Description Part Number
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 10M, 1/8W, 1% 12-7996
MISCELLANEOUS
* SOCKET 1 1/8 inch PCB MOUNT
4435-103
W1 Wire-#22AWG WHT 9 65/40 21-8543
W4 Wire-#22AWG BLK 0 65/40 21-8552
Ludlum Measurements, Inc. Page 4-3 March 2016
Models 43-93 & 43-93-2 Technical Manual Section 5
Section
5
Drawings and Diagrams
Model 43-93 Assembly View, Drawing 393 × 140
Model 43-93-2 Assembly View, Drawing 393 × 119
Mylar Window Replacement, Drawing 393 x 165A
1 1/8 inch Voltage Divider Circuit Board, Drawing 435 × 1325
1 1/8 inch Voltage Divider Component Layout, Drawing 435 × 1324
(2 sheets)
Ludlum Measurements, Inc. Page 5-1 March 2016
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