LUDLUM MODEL 19A

MICRO R METER

Revised October 2000 Serial No. 144020 and Succeeding

Serial Numbers

LUDLUM MEASUREMENTS, INC. 501 OAK ST., P.O. BOX 810 SWEETWATER, TX 79556 91 51235-5494 FAX: 91 51235-4672

REV #I ALTERATIONS I DATE I BY VALID 18-10-00 IDD\ I

W

U D

ALARM

@ ALARM

0

0

RES

MODEL 19A MICRO R METER

LUDLUM MEASUREMENTS, INC.

C f SWEETWATER, TEXAS

1 .

2 .

3 .

4 .

5 .

6 .

M I 9A Micro R Meter

TABLE OF CONTENTS

GENERAL ...................................................................................................

SPECIFICATIONS .........................................................................................

DESC~PTION OF CONTROLS AND FUNCTIONS .............................................

OPERATING PROCEDURES ...........................................................................

CALIBRATION .............................................................................................

MAINTENANCE ...........................................................................................

PARTS LIST ....................................................................................................

DRAWINGS AND DIAGRAMS ........................................................................... 10

page i

M19A Micro R Meter

The Ludlum Model 19A Micro R Meter is a portable survey instrument having the additional feature of an audio and visual alarm. The alarm circuit is adjustable from a meter scale deflection of 0 to off scale. The meter scale is logarithmic with a range of 0- 500 micro Whr.

The M 19A utilizes an internally-mounted, 1" x 1" NaI(T1) scintillator to offer an optimum performance in counting low-level gamma radiation. It is designed to be moisture and dust resistant.

The unit body is made of cast aluminum, including the meter housing. The meter housing is a rugged aluminum bezel with waterproof seals. The can is 0.90"

aluminum. Other operating features of the instrument include a unimorph speaker mounted to the instrument can with an audio ON-OFF capability, alarm reset pushbutton switch, and a three-position switch for selecting battery check or instrument ON.

The instrument is capable of using either standard flashlight batteries or nickel- cadmium rechargeable batteries. However, the M19A does not include circuitry for recharging the batteries.

All controls, including a calibration potentiometer, are internal. Two "D" cell batteries are located in an isolated compartment and easily changed from the front panel.

LINEARITY: Plus or minus 10% of full scale

INPUT IMPEDANCE: 0.1 megohm

HIGH VOLTAGE: Variable from 400 to 1500 volts DC, electronically regulated to within k 1 %

CALIBRATION STABILITY: Less than 3% variance to battery end point

SENSITIVITY: 30 k 10 millivolts

BATTERY COMPLEMENT: Two standard size "D" cell batteries, secured in a isolated compartment with screws and a gasket for dust and moisture proofing

BATTERY LIFE: Exceeds 600 hours with a fresh set of Alkaline "D" cell batteries (non-alarm condition)

AUDIO OUTPUT: Built-in unimorph speaker and ON-OFF switch provided on front panel

ALARM INDICATION: Audio and visual indication when above alarm threshold

ALARM RANGE: 0 to off-scale

COUNTING RANGE: 0-500 pWhr

RESPONSE: 10 pWhr to 50 pWhr, 6.5 seconds; 10 pWhr to 100 p€Uhr, 2.5 seconds; 10 pWhr to 500 pWhr, 0.5 seconds (Meter response times are measured with the instrument in a 10 pWhr background radiation field)

METER: I d , 2 1/2-inch scale, pivot-and-jewel suspension

DETECTOR: Photomultiplier coupled to a 1" x 1" NaI(T1) crystal mounted inside the instrument housing

FINISH: Instrument housing of drawn-and-cast aluminum fabrication with computer-beige, polyurethane enamel and silk-screened nomenclature

M 19A Micro R Meter

SIZE: 15.75 cm (6.2") H x 8.9 cm WEIGHT: 1.36 kg (3 lbs.), less (3.5") W x 21.6 cm (8.5") L, exclusive of handle

detector and batteries

3. DESCRIPTION OF CONTROLS AND FUNCTIONS

OFF-BAT-ON Selector Switch: A three-position switch for turning the instrument on and checking the battery status. A BAT TEST scale on the meter provides a visual means of checking the battery when the switch is in the BAT position. The ON position provides power to the instrument.

AUD ON-OFF Toggle Switch: In the ON position, operates the unimorph speaker, located on the left side of the instrument. The frequency of the clicks is relative to the rate of the incoming pulses. The higher the rate is,

the higher the audio frequency. The audio should be turned OFF when not required to reduce battery drain.

ALARM RES Pushbutton Switch: When depressed, this switch resets the alarm when the meter pointer is below the alarm threshold.

ALARM Light: A red lamp that comes on to give a visual alarm when radiation is above the alarm threshold.

The M19A is a simple instrument to operate. All controls are located on the front panel along with the battery compartment. The 1" x 1" NaI(T1) Scintillator is mounted internally.

r / NOTE: To open the Battery Lid, twist the lid button counterclockwise 1/4 turn. To close, twist clockwise 1/4 turn.

0 Open the lid and install two "D" size batteries. Note (+) (-) marks on the inside of the lid. Match the battery polarity to these marks.

NOTE: Center post of flashlight battery is positive.

0 Close the battery box lid.

0 Select the BAT position of the OFF-BAT-ON switch. Replace the batteries if the meter pointer is below the BAT TEST line.

0 Check for audio indication with the AUD ON-OFF switch.

0 Check the instrument for the proper meter scale indication with a known source.

NOTE: Instrument response time will vary with the radiation field intensity. Refer to the RESPONSE time in Section 2.

0 Position a check source to drive meter to alarm set point (set at 20-50pWhr at factory) causing instrument to alarm. Remove check source and depress the ALARM RES pushbutton to confirm that alarm will reset.

0 The instrument is ready for monitoring

M 19A Micro R Meter

4 The M19A radiation response is energy-sensitive. The detector plateau- characteristic must be determined for the anticipated radiation nuclide. The following is an example calibration:

Remove the instrument from its case (referred to as "can" from hereon).

0 Adjust Alarm Set control fully clockwise to keep the alarm circuit from tripping during calibration.

0 With the instrument off, remove the detector coax cable connection at the junction of C57-R27 on the circuit board.

0 Connect a Ludlum Model 500 h lser to the C57-R27 junction.

Plateau instrument using Americium using the HV adjust poten- 24 1

tiometer .

0 Determine the plateau center voltage.

0 Removecan.

0 Measure detector operating voltage (H.V.) at C57-R27 and record for future reference.

NOTE: Measure High Voltage with a Model 500 pulser or a High Impedance voltmeter with a high meg probe. If one of these instruments is not available use a voltmeter with a minimum of 1000 megohm input resistance.

Replace instrument can. 0 Set the pulse height at 80 millivolts,

negative.

Calibrate the scales as shown in Table 1. Use the CAL control for the mid scale or lower meter reading and the SPAN control for the upper meter reading. Alternate between the two controls to insure meter linearity between readings.

Table I

READING PULSES/MINUTE

5 50

500

875 8,750

87,500

0 Reconnect detector coax to the junction of C57-R27. Replace instrument can.

NOTE: The detector is not light-tight outside of the can.

0 Take the M19A to a certified calibration range. Place the instrument in a 1OOpWhr (exposure rate) radiation field. The depression at the front of the instrument can indicates the detector axis center, and approximately 3/4 of an inch from the depression end is the detector 1" X 1" NaI scintillator center. Expose the radiation source and adjust the CAL control (located on the calibration bd. inside instrument can) for the correct meter indication.

0 Place the instrument in a calibrated 500pWhr radiation field. Adjust the SPAN control for correct meter reading.

0 Confirm instrument linearity by placing the instrument back in 100pWhr field. If the meter is nonlinear, alternate between the CAL and SPAN controls for meter correction. Adjust the Cal control for the lower reading and the SPAN control for the upper reading.

M19A Micro R Meter

17 Position meter pointer at the desired alarm set point with radiation source. Adjust the ALARM SET control to the desired alarm threshold. Minimum setting is 0 on the meter scale and maximum setting is full scale deflection. (Factory set at 20-50 y w w

When the alarm circuit is energized, both the audio and visual indications should occur. Depressing the ALARM RES pushbutton switch resets the alarm circuit when the meter pointer is below the alarm threshold.

0 Recheck all operating functions of the instrument prior to use.

Instrument maintenance consists of keeping the instrument clean and periodically checking the batteries and the calibration.

An instrument operational check should be performed prior to each use by exposing the detector to a known source and confirming the proper reading on each scale.

Recalibration should be accomplished after any maintenance or adjustment of any kind has been performed on the instrument. Battery replacements are not considered to be maintenance and do not normally require the

year. Check the appropriate regulations to determine required recalibration intervals.

The batteries should be removed and the battery contacts cleaned of any corrosion at least every three months. If the instrument has been exposed to a very dusty or corrosive atmosphere, more frequent battery servicing should be used.

Use a spanner wrench to unscrew the battery contact insulators, exposing the internal contacts and battery springs. Removing the handle will facilitate access to

instrument to be recalibrated.

recalibration at intervals no greater than one

these contacts. Ludlum Measurements recommends

NOTE

NEVER STORE THE INSTRUMENT OVER 30 DAYS WITHOUT REMOVING BATTERIES. ALTHOUGH THIS INSTRUMENT WILL OPERATE AT VERY

HIGH AMBIENT TEMPERATURES, BATTERY SEAL FAILURE CAN OCCUR AT TEMPERATURES AS LOW AS 100" FAHRENHEIT.

M 19A Micro R Meter

Ref. No. Description

1 1 9 A Mirrn R Mptpr

UNIT Completely Assembled Model 19A Micro R Meter

Circuit Board, Drawing 363 X 440

BOARD

CAPACITORS

C38 C40 C4 1 C42 C50 C56 c57 c 102 C103 C 106 C109 c112 C113 C115 C117 C119 c121 C 126 C134 C163 C170 C171 C191 c200 C226-C227 C228

TRANSISTORS

Q6 Q15

Assembled Circuit Board

0.0015yF, 3KV, C 0.0015pF, 3KV, C 0.0015pF, 3KV, C 0.0027pF, 3KV, C 100pF, 3KV, C 100pF, lOV, DT 100pF, 3kV, C 100pF, lOV, DT lOpF, 20V, DT 0.001pF, lOOV, C O.OlpF, 1OOV , C 470pF, lOOV, C O.OlpF, lOOV, C 100pF, lOV, DT 100pF, lOOV, C 0.001pF, lOOV, C 330pF, lOOV, C lOyF, 20V, DT 100pF, lOV, DT O.OlyF, lOOV, C O.lpF, lOOV, C lyF, 35V, DT 0.0015pF, 3KV, C 4.7pF, lOV, DT O.OlpF, lOOV, C O.lpF, 35V, DT

2N3904 MPS6534

Part No.

48-21 17

53 63 -602

04-55 18 04-55 18 04-55 18 04-5520 04-5532 04-5576 04-5532 04-5576 04-5592 04-55 19 04-5523 04-5555 04-5523 04-5576 04-5527 04-55 19 04-553 1 04-5592 04-5576 04-5523 04-552 1 04-5575 04-55 18 04-5578 04-5523 04-5574

05-5755 05-5763

M I 9A Micro R Meter

444 2N3904 496 2N3904 4145 MPS6534 4218 MPSWO1 4224 MPS6534 4225 2N3904

INTEGRATED CIRCUITS

u1 u 2 u 3 u 4 u 5 U6 u 7 UlOl U198

DIODES

CR94

CR169 CR175 CR201-cR202

CR166-CR167

RESISTORS

R18 R27 R36 R46 R47 R63 R64 R65 R66 R68 R70 R72 R75 R76 R77 R78 R79 R8 1 R83 R84

CA3096 TLC372 CD4098 CA3096 ICM7555 TLC27M7IP MAX63 1

TLC27M7IP LM385Z-1.2

1N4148 1 N4007 1 N4007 1N4007 1N4148

lk 22k 10M 10k 1G 82k lk 10k lk 8.2k 4.7k SAT (TYPICALLY 33k) 33k 100 OHM 2.2k 22k lOOk 10k lOOk 470k

05-5755 05-5755 05-5763 05-5778 05-5763 05-5755

06-6023 06-6265 06-6066 06-6023 06-6136 06-6248 06-6249 05-5808 06-6248

07-6272 07-6274 07-6274 07-6274 07-6272

10-7009 10-7070 10-703 1 10-7016 12-7686 10-7022 10-7009 10-7016 10-7009 10-7015 10-7014

10-7019 10-7004 10-70 12 10-7070 10-7023 10-70 16 10-7023 10-7026

M I 9A Micro R Meter

R86 R87 R89 R9 1 R128 R137 R138 R147 R150 R159 R172 R177 R189 R196 R204 R205 R206 R207 R208 R209-R2 10 R212 R213 R214 R215 R2 16-R2 17

TRANSFORMERS

T165

INDUCTORS

L13

MISCELLANEOUS

* *

* *

2.7M 10k 100k 4.7k lOOk 10k 1M SAT (TYPICALLY 750k) SAT (TYPICALLY 2.2k) 10k 47k 200 OHM 200 OHM l k 1M 100k 22k 5.6k 24.3k 294k lOOk l k 24.3k SAT (TYPICALLY 10k) 1 OOM

L8050

IM6-470UH-5

CLOVERLEAF RECEP- TACLES 01 1-6809 (6 EACH) WALDON 16-06-0007 LAR- GE RECEPTACLE JACK-TEST 1128-09-03 19 SPACER-423-175 (2 EA)

10-7029 10-7016 10-7023 10-7014 10-7023 10-7016 10-7028

10-70 16 10-7020 10-7006 10-7006 10-7009 10-7028 10-7023 10-7070 10-7042 12-7700 12-7632 10-7023 10-7009 12-7700

10-7036

40-0902

2 1-9600

18-877 1

18-8792

18-8806 18-8992

M I 9A Micro R Meter

Calibration Board. Drawinp 367 x 48

BOARD Assembled Calibration Board

RESISTORS

Rl-R2 lOOk TRIMMER R3 500 OHM TRIMMER R4 10k R5 lOOk TRIMMER R6 lOOk

MISCELLANEOUS

P1 CONN-640456-8 MTAlOO

Wiring Diagram, Drawing 367 X 47

AUDIO

DS2

CONNECTORS

J1 52 J3

SWITCHES

s 1 s 2 s3

BATTERY

B 1 -B2

MISCELLANEOUS

DS 1 *

* M1 *

UNIMORPH 10 1-00 1

CONN-1-640442-3 MTA 100 CONN-640442-2 MTA 100 CONN-640442-8 MTA 100

PA-600-2 10 30-1-PB GRAYHILL 7 10 1-SYZ-QE

BATTERY-DURACELL "D"

BULB-3 3 3 8 LAMP-HOLDER 10 1-8430-09-20 1 LENS-RED 140-1471 PORT BEZEL WIMOV ASSY METER BEZEL W/GLASS WIO SCREWS

5367-064

09-6823 09-6848 10-7016 09-6823 10-7023

13-8039

21-9251

13-8138 13-8178 13-8184

08-6501 08-65 17 08-65 1 1

21-93 13

21-9307

2 1-94 10 21-9411 4363-188

4363-352

M 19A Micro R Meter

*

*

* *

*

* * *

* * *

METER MVMNT 919492 1 mA M19A BATTERY BOX LID W/CE BATTERY CONTACT ASSY DEEP PORTABLE CAN ASSY M19A CASTING M19A MAIN HARNESS PORTABLE KNOB BATTERY LID W/LATCH SET PORT LATCH KIT W/O BATTERY LID SWITCH SEAL (TOGGLE) SWITCH SEAL (P/B) REPLACEMENT DETECTOR ASSY X-TAL TUBE ASSY- M12S PM TUBE- 1-1/8" CAL COVER W/SCREWS

15-8030 9367-125

200 1-042

4363-6 15 9367-055 8367-065 08-6613

9367-032

4363-349 08-66 10 08-66 1 1

47- 1574 2004-06 1 01-5367 9363-200

M 19A Micro R Meter

DRAWINGS AND DIAGRAMS

Main Board, Drawing 363 x 440 Main Board Component Layout, Drawing 363 x 441 Calibration Board, Drawing 367 x 48 Wiring Diagram, Drawing 367 x 47

page 10

Rl5

PI -6 < E:+SV,4=CNO

tl.22V PI -4 <-, PI -2

PI -5

P I - I

PI -3

PI -E

ZN3904 R128

R65 8=+5V ,4=CND

,PI -7

UPDATED - LUDLUfi MSUREnENTS INK, DR CKE

DSGN DL - NErT HIGHER A S S Y ,

07/25/96

10/29/91

. 9 T I T L E ~ nA lN BOARD +Lo EOARDB 5363-602

c 19A / 191-1 3J 440 S E R I E S SHEET

19-Au~-93 S8363682 , I

I SHEET I OF I

B O A R D DIMENSIONS: WIDTH = 5 , 1 4 7 " HEIGHT=2 , 8 1 0 "

MOUNTING HOLE LOCAT IONS ~

1 , X=O , 1 4 0 " Y=0 I 1 3 4 'I

2 I X=4 ,897"

RE lmK

ri -3 )-..5~

k K A L A R I SEl

P I -5

P I -2

t5V

i HtViSlONS DESCR I PT iON I DATE IAPPROVE EFF I AUTHORITY I ZONE 1 L l R I

J2 n A l N BOARD