LUDLUM 5 Technical Manual

Geiger counter

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LUDLUM MODEL 5
GEIGER COUNTER
May 2014
Serial Number 236626 and Succeeding
Serial Numbers

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Summary of Contents for LUDLUM 5

  • Page 1 LUDLUM MODEL 5 GEIGER COUNTER May 2014 Serial Number 236626 and Succeeding Serial Numbers...
  • Page 2 LUDLUM MODEL 5 GEIGER COUNTER May 2014 Serial Number 236626 and Succeeding Serial Numbers...
  • Page 3 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.
  • Page 4: Table Of Contents

    Batteries Troubleshooting Troubleshooting Electronics which utilize GM Detectors Troubleshooting GM Detectors Recycling Parts List Model 5 Geiger Counter Main Board, Drawing 464 × 272 HV Power Supply Board, Drawing 464 × 249 Drawings and Diagrams Ludlum Measurements, Inc. May 2014...
  • Page 5: Introduction

    Technical Manual Section 1 Section Introduction he Model 5 is a self-contained portable Geiger Counter with two internal Geiger-Mueller (GM) tubes and five linear ranges used in combination with exposure rate or meter dials. The first three ranges use an LND 71210 (or equivalent), while the lower two ranges use an LND 71412 (or equivalent).
  • Page 6: Getting Started

    (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 5 serial number is located on the front panel below the battery compartment.
  • Page 7: Battery Test

    Reading the Meter Face Dial Reading the meter face is very important for consistent measurements. The Model 5 typically has an exposure rate 0-2.0 mR/hr meter face. The following examples are intended to help the user interpret the correct reading.
  • Page 8: Operational Check

    BAT OK If the needle is pointing as indicated above and the instrument range selection switch is on the ×0.1 scale multiple, then the reading is 1.5 mR/hr (multiplied by) ×0.1 = .00015 R/hr. The same needle indications on successive ranges would be: ×1 = 1.5 mR/hr (or .0015 R/hr)
  • Page 9: Specifications

    : within 15% of true value from 60 keV - 3 MeV Energy Response : in excess of 1000 R/hr Saturation : 6.4 cm (2.5 inch) arc, 1 mA, pivot-and-jewel suspension Meter : 0-2 mR/hr, (others available) Meter Dial...
  • Page 10 -20 to 50 ˚C (-4 to 122 ˚F) Temperature Range: : 24.1 x 8.9 x 21.6 cm (9.5 x 3.5 x 8.5 inch) (H x W x L), including Size instrument handle : 2 kg (4.4 lb) including batteries and detectors Weight : cast and drawn aluminum with beige powder-coating.
  • Page 11: Identification Of Controls And Functions

    Section 4 Section Identification of Controls and Functions Meter : 6.4cm (2.5 inch) arc, 1 mA analog type with pivot-and-jewel suspension. Typical meter dial is 0-2 mR/hr and BAT TEST Range Selector Switch : A six-position switch marked , ×1000, ×100, ×10, ×1, ×0.1.
  • Page 12 Model 5 Geiger Counter Technical Manual Section 4 : Provides meter response. Selecting the fast, ˝ F-S Toggle Switch ˝ position, of the toggle switch provides 90% of full-scale meter deflection in four seconds. In the slow, ˝ ˝ position, 90% of full-scale meter deflection takes 22 seconds.
  • Page 13: Safety Considerations

    The operator or responsible body is cautioned that the protection provided by the equipment may be impaired if the equipment is used in a manner not specified by Ludlum Measurements, Inc. The Model 5 Geiger Counter is marked with the following symbols: CAUTION (per ISO 3864, No.
  • Page 14: Cleaning And Maintenance Precautions

    European Union. Cleaning and Maintenance Precautions The Model 5 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 cleaning or performing maintenance on the instrument: 1.
  • Page 15: Maintenance

    Maintenance Instrument maintenance consists of keeping the instrument clean and periodically checking the batteries and the calibration. The Model 5 instrument may be cleaned with a damp cloth (using only water as the wetting agent). Do not immerse instrument in any liquid. Observe the following precautions when cleaning: 1.
  • Page 16 Model 5 Geiger Counter Technical Manual Section 6 must be scraped off and/or washed using a paste solution made from baking soda and water. Use a spanner wrench to unscrew the battery contact insulators, exposing the internal contacts and battery springs. Removal of the handle will facilitate access to these contacts.
  • Page 17: Troubleshooting

    (1) sticky meters, (2) battery contacts. Note that the first troubleshooting tip is for determining whether the problem is with the electronics or with the detector. A Ludlum Model 500 Pulser is invaluable at this point, because of its ability to simultaneously check high voltage, input sensitivity or threshold, and the electronics for proper counting.
  • Page 18 Model 5 Geiger Counter Technical Manual Section 7 SYMPTOM POSSIBLE SOLUTION Nonlinear Readings Check the high voltage ( ) using a Ludlum Model 500 Pulser (or equivalent). If a multimeter is used to check the , ensure that one with...
  • Page 19: Troubleshooting Gm Detectors

    If damage is evident, the tube must be replaced. 2. Check the . For most GM tubes, the voltage is normally 900 Vdc, or 460-550 Vdc for “peanut” tubes (Ludlum Model 133 series). 3. Wires to the tube may be broken or the crimped connector could have a loose wire.
  • Page 20: Recycling

    To this end, Ludlum Measurements, Inc. strives to supply the consumer of its goods with information regarding reuse and recycling of the many different types of materials used in its products. With many different agencies - public and private - involved in this pursuit, it becomes evident that a myriad of methods can be used in the process of recycling.
  • Page 21: Main Board, Drawing 464 × 272

    Model 5 Geiger Counter Technical Manual Section 9 Section Parts List Reference Description Part Number Model 5 Geiger UNIT Completely Assembled Counter Model 5 Geiger Counter 48-1607 Main Board, BOARD Main Circuit Board 5464-272 Drawing 464 × 272 CAPACITORS 470pF, 100V 04-5668 0.1µF, 35V-T...
  • Page 22 Model 5 Geiger Counter Technical Manual Section 9 Reference Description Part Number CMXT3904 05-5888 MAX986EUK-T 06-6601 MAX4541EKA-T 06-6637 CD74HC4538M 06-6297 LMC7111BIM5X 06-6410 LT1304CS8-5 06-6434 MIC1557BM5 06-6457 MAX985EUK-T 06-6459 ICL7660SCBA 06-6437 MAX4542EKA-T 06-6638 SN74AHHC1G00GW 06-6644 DIODES CMPD2005S 07-6468 CMSH1-40M 07-6411 CR3-CR4...
  • Page 23 Model 5 Geiger Counter Technical Manual Section 9 Reference Description Part Number 68.1K, 1/4W, 1% 12-7881 100K, 1/4W, 1% 12-7834 1K, 1/4W, 1% 12-7832 1M, 1/4W, 1% 12-7844 475K, 1/4W, 1% 12-7859 100K, 1/4W, 1% 12-7834 100K, 1/4W, 1% 12-7834 90.9K, 1/4W, 1%...
  • Page 24 Model 5 Geiger Counter Technical Manual Section 9 Reference Description Part Number DIODES CR1-CR3 CMSD2004S 07-6417 CMSH1-40M 07-6411 POTENTIOMETER 25K, 8026EKX-253, OJ ADJ. 09-6832 NOT USED RESISTORS R1-R2 1M, 1/4W, 1% 12-7844 1M, 1/4W, 1% 12-7844 4.75K, 1/4W, 1% 12-7858...
  • Page 25: Hv Power Supply Board, Drawing 464 × 249

    MAIN CIRCUIT BOARD LAYOUT, Drawing 464 × 273 (2 sheets) HV POWER SUPPLY BOARD, Drawing 464 × 249 HV POWER SUPPLY BOARD LAYOUT, Drawing 464 × 250 (2 sheets) WIRING DIAGRAM, Drawing 464 × 351 ENERGY RESPONSE for LMI Model 5 Ludlum Measurements, Inc. Page 10-1 May 2014...
  • Page 35 Energy Response for LMI Model 5 Low Range High Range Cs-137 1000 10000 Gamma Energy (keV)

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