LUDLUM 42-49 Technical Manual Download

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Model 42-49 Neutron Detector

Technical Manual

Section 6

Ludlum Measurements, Inc.

Page 6-1

December 2017

Parts List

Reference

Description

Part Number

UNIT

Completely Assembled

Model 42-49

Neutron Detector

47-4057

2 EA.

SCREW-6-32 X 3/8 BRASS KNURL

17-8659

Model 42-49 SPHERE ASSY

47-4058

4 EA.

SCREW-#8 X ¾ FH SHT MTL

17-9085

MODEL 43-4, 324 HANDLE

7005-060

7.7 inch SPHERE

7014-858

2 EA.

INSERT E-Z LOK 6-32

20-9066

8 EA.

8 INCH HDPE ROD

29-9985

MODEL 42-49 DET + MODERATOR

47-4059

1 EA.

O RING-2-116

16-8293

1 EA.

O RING-2-148

16-8340

2 EA.

SCREW-8-32 X 5/8 SOC SET

17-8765

MODEL 42-49 PROBE ASSY

4014-587

He TUBE 25185 2 ATM

01-5793

CONNECTOR, UG706/U

4478-011

TUBE BODY ASSY

2014-595

MODEL 42-30, 42-31

DETECTOR SPACER

7005-056

CONNECTOR END

7014-598

CBL-MODEL 42-49 RG178 3INCH

8014-599

MODEL 42-49 MODERATOR

7014-591

MODEL 42-49 DETECTOR STRAP

7014-592

Section

Model 42-49
Neutron Detector

Summary of Contents for 42-49

Page 1: ...LUDLUM MODEL 42 49 NEUTRON DETECTOR December 2017 ...

Page 2: ...LUDLUM MODEL 42 49 NEUTRON DETECTOR December 2017 ...

Page 3: ...Repacking 2 Connecting to an Instrument 2 1 Specifications 3 Safety Considerations 4 Environmental Conditions for Normal Use 4 1 Cleaning Instructions and Precautions 4 1 Calibration 5 Calibration 5 1 Operating Voltage Plateau 5 1 Gamma Rejection Check 5 2 Conversion Chart 5 3 Parts List 6 ...

Page 4: ...ese gamma rays in the detection process A common reaction for the conversion of slow neutrons into directly detectable particles is n 3 He 3 H 1 H 0 764 MeV The Ludlum Model 42 49 utilizes this reaction in the form of helium 3 3 He which fills the gas proportional tube of the detector The Model 42 49 is designed to be used with portable counting instruments and has a top bracket that allows for co...

Page 5: ...lManual Section1 Ludlum Measurements Inc Page 1 2 December 2017 Note The detector does not contain any consumable materials Note If the detector is used in a manner not intended by the manufacturer the detector may not function properly ...

Page 6: ...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 on the Support tab and selecting Repair and Calibration from the drop down menu Then choose the appropriate Repair and Calibration division where you ...

Page 7: ... mV input sensitivity Sensitivity 100 cpm mrem hr 241 AmBe fast neutrons Gamma Rejection 10 cpm or less through 10 R hr 100 mSv hr 137 Cs Detection Range thermal to approximately 12 MeV Energy Response thermal to 12 MeV follows the radiation protection guide curve for neutron dose Input Sensitivity 2 mV Operating Voltage approximately 1200 V Connector series C others available Temperature Range 20...

Page 8: ...less than 95 non condensing Pollution Degree 2 as defined by IEC 664 Normally only nonconductive pollution occurs Temporary conductivity caused by condensation is to be expected Cleaning Instructions and Precautions The detector may be cleaned externally with a damp cloth using only water as the wetting agent Do not immerse the instrument in any liquid Observe the following precautions when cleani...

Page 9: ...em hr 241 AmBe neutron source Run a plateau as follows Taking one minute counts record the count rate for 25 volt incremental steps from 1000 volts through a region in which the count rate steadily increases becomes relatively constant flattens out and then increases again A typical range will be 1000 1250 volts The flattest portion of this region is the desired plateau The value in the middle of ...

Page 10: ...ly 120 cpm mrem hr Gamma Rejection Check With the Model 42 49 connected to the Model 2200 adjust the Model 2200 HV to the assumed operating voltage determined above Remove the Model 42 49 detector from the moderator and place in a 10 R hr 137 Cs gamma radiation field Take a one minute count If more than 10 counts are observed for the one minute period decrease the operating voltage until the count...

Page 11: ...0 mrem hr Take a one minute count and record the value including the range scale setting of counting instrument Repeat for the dose equivalent rates shown in Table 1 The values in Table 1 and their corresponding measured values represent a conversion chart for use in relating other measured values to actual dose equivalent rates Table 1 Ref Point mrem hr Reading cpm Range Scale 400 200 80 20 8 2 ...

Page 12: ...05 060 7 7 inch SPHERE 7014 858 2 EA INSERT E Z LOK 6 32 20 9066 8 EA 8 INCH HDPE ROD 29 9985 MODEL 42 49 DET MODERATOR 47 4059 1 EA O RING 2 116 16 8293 1 EA O RING 2 148 16 8340 2 EA SCREW 8 32 X 5 8 SOC SET 17 8765 MODEL 42 49 PROBE ASSY 4014 587 3 He TUBE 25185 2 ATM 01 5793 CONNECTOR UG706 U 4478 011 TUBE BODY ASSY 2014 595 MODEL 42 30 42 31 DETECTOR SPACER 7005 056 CONNECTOR END 7014 598 CBL...

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