LUDLUM 2221 Manual

LUDLUM 2221 Manual

Portable scaler ratemeter

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LUDLUM MODEL 2221
PORTABLE SCALER RATEMETER
Revised March 2016
Serial Number 161568 and Succeeding
Serial Numbers

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Summary of Contents for LUDLUM 2221

  • Page 1 LUDLUM MODEL 2221 PORTABLE SCALER RATEMETER Revised March 2016 Serial Number 161568 and Succeeding Serial Numbers...
  • Page 2 LUDLUM MODEL 2221 PORTABLE SCALER RATEMETER Revised March 2016 Serial Number 161568 and Succeeding Serial Numbers...
  • Page 3: Statement Of Warranty

    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 5: Table Of Contents

    Model 2221 Portable Scaler Ratemeter March 2016 TABLE OF CONTENTS 1. GENERAL ..........................1 2. SPECIFICATIONS ........................1 3. DESCRIPTION OF CONTROLS AND FUNCTIONS ............2 4. OPERATING PROCEDURES ....................4 4.1 Initial Preparation ........................4 4.2 Operating Point ........................4 4.3 Limitation of Controls ......................4 5.
  • Page 6: General

    Model 2221 Portable Scaler Ratemeter March 2016 1. GENERAL The Ludlum Model 2221 Portable Scaler A single channel analyzer is also featured in Ratemeter is a self-contained counting this unit for use in gamma spectrum analysis. instrument designed for operation with The analyzer may be switched on or off, scintillation, proportional, or GM detectors.
  • Page 7: Description Of Controls And Functions

    Model 2221 Portable Scaler Ratemeter March 2016  SIZE: 22.9 x 10.9 x 25.4 cm (9 x 4.3 x  FINISH: polyurethane enamel with 10 in.) (H x W x L), including handle silk-screened nomenclature  WEIGHT: 2.5 kg (5.5 lb), including batteries 3.
  • Page 8 Model 2221 Portable Scaler Ratemeter March 2016 OUT position: The SCA is set up as a CALIBRATION CONTROLS: gross counter. All detector pulses above  WIN: 20-turn potentiometer used to the threshold are counted. adjust window width when the window toggle switch, WIN, is in the "IN"...
  • Page 9: Operating Procedures

    Model 2221 Portable Scaler Ratemeter March 2016 4. OPERATING PROCEDURES marked difference apparent 4.1 Initial Preparation contribution of these three sources of count. ● Unscrew battery door latch. In the singular case of the GM detector, a ● Install 4 "D" size batteries in the battery minimum operating voltage is required to holder.
  • Page 10: Determining Instrument Plateau And Selecting Operating Point

    Model 2221 Portable Scaler Ratemeter March 2016 5. DETERMINING INSTRUMENT PLATEAU AND SELECTING OPERATING POINT ● Set WIN ON/OFF to OFF. ● Expose the detector to a source and again make a plot of voltage versus count. ● Set MINUTES switch to 0.1 minutes.
  • Page 11: Overload Detection Calibration

    ● Expose detector to radiation field and while observing ratemeter, increase field intensity ● Full-scale instrument analog meter reading until a decrease in count rate is noticed. For = 200 mR/hr (2 mSv/h). Set the Model 2221 alpha scintillators, detector...
  • Page 12: Test Pushbutton/Display Calibration

    Model 2221 Portable Scaler Ratemeter March 2016 ● Switch Ratemeter Multiplier switch to the ● Confirm HV will adjust from 400 to X100 position and the Response switch to 2400-2500 volts. Ensure HV displayed “F.” reading tracks within 2% of HV output.
  • Page 13: Overhaul Procedure

    Then set HV for approximately 1000 Vdc. ● Connect low-voltage power supply, capable ● Connect voltmeter to pin 1 of U3 of supplying 4.0-5.0 Vdc to the Model 2221 (TLC27M7IP). and plug in amplifier/power supply board (component side to back of instrument).
  • Page 14: Processor Board Checkout

    Model 2221 Portable Scaler Ratemeter March 2016 ● With the HV still set at 1000 Vdc, pin 7 of ● Switch the Window IN/OUT switch to the U3 should be approximately 1 0.1 Vdc IN position and verify that the pulses are present at pin 7 of U105 from 10 to 20 mV while pressing the HV test pushbutton.
  • Page 15 Model 2221 Portable Scaler Ratemeter March 2016 ● With supply voltage set at +5 0.15 Vdc, ● Connect oscilloscope to pin 9 of U10 turn instrument ON and observe display = (ICM7556) and decade sweep generator 8.8:8.8:8.8 for approximately 2 seconds, down to the 1k range.
  • Page 16: Functional/Chassis Checkout

    Model 2221 Portable Scaler Ratemeter March 2016 9.3 Functional/Chassis Checkout  Confirm display reads 8.8:8.8:8.8 for approximately 2 seconds, then 261010  This procedure requires a checked-out indicating the program version. amplifier/power supply board and processor  board. ● Connect positive voltmeter lead to pin 7 of U3 (TLC27M7IP) on the amplifier/power ...
  • Page 17 Model 2221 Portable Scaler Ratemeter March 2016 ● With the THR control adjusted for 100, Disconnect over-range simulator and confirm overrange function is defeated. adjust R174 Gain (labeled G) for 1.5 Then adjust to fully clockwise position. millivolt input sensitivity.
  • Page 18 Model 2221 Portable Scaler Ratemeter March 2016 ● Turn Lamp switch to the ON position and each digital number count sequence from least significant digit to most significant confirm two lamps in the display and two digit (MSD). Decade pulser count rate to lamps below the meter are illuminated.
  • Page 19: Parts List

    Model 2221 Portable Scaler Ratemeter March 2016 10. PARTS LIST Ref. No. Description Part No. C154 0.0015F, 3kV, C 04-5518 C164 0.1F, 100V, C 04-5521 Model 2221 Portable Scaler Ratemeter C165 0.1F, 100V, C 04-5521 UNIT Completely Assembled Model 2221...
  • Page 20: Processor Board, Drawing 261 X 91

    Model 2221 Portable Scaler Ratemeter March 2016 12-7748 12-7749 1M, 1% 12-7609 12-7751 12-7748 470k 12-7757 12-7748 R100 470k 12-7757 12-7748 R101 100k 12-7747 12-7748 R102 1M, 1% 12-7609 12-7758 R171 10k TRIMMER 09-6822 4.7k 12-7755 R172 100k TRIMMER 09-6823...
  • Page 21: Calibration Board, Drawing 261 X 59

    Model 2221 Portable Scaler Ratemeter March 2016 CD4056 06-6095 BOARD Assembled Board 5261-075 CD4056 06-6095 CD74HC573 06-6093 VOLTAGE REFERENCES 87C257 06-6278 80C51FA 06-6236 LM385Z-1.2 05-5808 RDD104 06-6060 LM385Z-1.2 05-5808 LM358 06-6024 LM385Z-1.2 05-5808 CD74HC238 06-6246 RESISTORS DIODE 12-7754 CR45 1N4148...
  • Page 22: Backplane Board, Drawing 261 X 60

    Model 2221 Portable Scaler Ratemeter March 2016 BOARD Assembled Backplane Board 5261-076 RS-232 Board, Drawing 261 X 179 BOARD Assembled RS-232 Board 5261-179 DIODE 1N5819 07-6306 CAPACITORS CONNECTORS 4.7F, 20V, SMT 04-5653 J1-J2 EZA22DRSN 13-8181 10F, 20V, SMT 04-5655 640456-7 MTA100 13-8115 4.7F, 20V, SMT...
  • Page 23: Rs-232 Port Addition

    The Model 2221 RS-232 port addition allows available. the Model 2221 data to be read as output to a computer or serial printer, by dumping either The Model 2221 will dump the data, no matter the ratemeter or scaler reading as desired.
  • Page 24: Drawings And Diagrams

    Model 2221 Portable Scaler Ratemeter March 2016 12. DRAWINGS AND DIAGRAMS Amplifier/Power Supply Board Schematic, Drawing 261 x 56 Amplifier/Power Supply Board Component Layout, Drawing 261 x 205 Processor Board Schematic, Drawing 261 x 91 Processor Board Component Layout, Drawing 261 x 103...

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