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Physical Characteristics:
Height: 4 (102 mm)
Length: 4 (102 mm)
Width: 3.5 (89 mm)
Weight: 0.66 lbs (302 g)
Capable of charging any self-reading dosimeter
· Conforms to ANSI N42.6-1980
· Operates on one 1.5 V D cell battery
· Has the ability to Kick or remove all residual charge from dosimeters properly, which prevents spurious upscale fiber movement
· Reading light to allow for easy charging/viewing
· Protects dosimeters from excessive charging force
· ABS Plastic case, blue finish
· Temp Range: 0 to 120 F (-18 C to 50 C)
MODEL 909 CHARGER INSTRUCTION MANUAL
1 .0 INTRODUCTION
The Arrow-Tech, Inc (AT) (DCA) Model 909 Dosimeter Charger is a totally self-contained, battery-operated instrument that conforms to ANSI N42.6-1980 and is capable of charging any self-reading pencil dosimeter. Unlike other model and make chargers, which do not "kick" all dosimeters properly, this Model 909 assures grounding of the dosimeter charging pin and removal of the residual charge, also known as "kick". Failure to remove this residual charge can cause spurious upscale fiber movement of 2 to 8% of the full scale length, which could be falsely interpreted as either additional radiation exposure or excessive drift. When Model 909 automatically "kicks" low range dosimeters, a small upscale fiber jump will be seen. This stabilizes the reference readings, resulting in more accurate radiation exposure readings.
The charger is contained in a two-part plastic case held together with a single captive screw. The CHARGE POST is located in the upper left-hand corner and the ZEROING KNOB in the upper right-hand corner and the READ LIGHT push.rod on the ZEROING KNOB. (See Figures 1 and 3). The CHARGE POST contains spring clips which guarantee constant ground contact. The READ LIGHT pushrod switch permits reading of the dosimeter without removing it from the CHARGE POST. The ZEROING KNOB adjusts the fiber position on the dosimeter. The dosimeter charger circuit is powered by a 1.5 volt battery and is capable of producing a variable voltage from 100 to 220 volts at the center electrode of the CHARGE POST. The threads on the light bracket lamp socket have been slightly deformed to reduce the possibility of the lamp vibrating loose. It requires slightly more torque to install or remove the lamp.
2.0 OPERATION
2.1 BATTERY INSTALLATION
(CAUTION: Do not use an alkaline battery. Use a carbon battery only.)
2.1.1 Unscrew single captive screw on back of case and remove charger bottom.
2.1.2 Install a "D" cell (1.5V) in the battery holder. Make sure that the positive terminal of the battery is installed at the end of the battery holder marked "+". Reassemble the charger. (See Figs. 4 & 5).
2.2 CHARGING (ZEROING) DOSIMETER
(NOTE: Please read entire instructions before charging dosimeter).
2.2.1 DO NOT press "PUSH ROD" when charging a dosimeter. The dosimeter could be damaged.
2.2.2 Remove the plastic cap from the charging end of the dosimeter.
2.2.3 Place dosimeter on CHARGE POST and push down firmly until the dosimeter barrel makes contact with the pedestal base. Failure to do so may result in erratic behavior of the dosimeter fiber or the charger. The fiber image, as seen through the eyepiece end of the dosimeter will now move fluidly across the scale when the ZEROING KNOB is rotated. IT IS IMPOSSIBLE TO DAMAGE A DOSIMETER BY EXERTING TOO MUCH PRESSURE WHEN USING A DCA CHARGER.
2.2.4 Slowly rotate the ZEROING KNOB until the fiber is at zero. In the case of low range dosimeters (less than 10 R), the fiber may have to be placed to the left of zero to accommodate the "kick" or fiber movement. See the dosimeter instruction sheet or INTRODUCTION 1.0 above for an explanation of "kick".
2.2.5 Do not remove the dosimeter from the CHARGE POST, but release the pressure until it sits loosely on the pedestal.
2.2.6 Check the reading by pressing the READ LIGHT pushrod to illuminate the scale. If desired, rezero until the fiber is exactly on zero.
2.3 TO READ DOSIMETER
Place the dosimeter lightly on the CHARGE POST. (Do not push down).
Press the READ LIGHT pushrod to illuminate the scale.
Read the dosimeter. To rezero the dosimeter, follow the procedure previously described under CHARGING (ZEROING) DOSIMETER.
2.4 SPECIFICATIONS
DIMENSIONS .............Approx. 4x4x3.5 inches
WEIGHT WITH BATTERY .......less than 1.1 lbs.
POWER SUPPLY .......................1.5 volt, D-cell
MAXIMUM VOLTAGE ...................220 volts DC CONFORMS TO ANSI N42.601980
'Patent No. 4,224,522
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