Instruction on use of charger

Operation
Accumulated radiation is read directly on an internal calibrated scale. A Dosimeter Charger ( such as the Jordan 750-5) is required in order to return the dosimeter to zero after each exposure period if desired.

One end of the dosimeter contains an optical eye-piece; the opposite end is sealed by a diaphragm switch which houses the insulated steel charging pin. The instrument is charged (set to zero) by pressing the charging pin onto the charging socket on the charger.

Arrow-Tech Model 138 , 0 - 200 mR



Jordan 750-5 charger

After properly charging the dosimeter, the fiber will remain on zero.

The Charging Process

FIRST Check to see if the light comes by reading a dosimeter, if the light does not come on it could mean there is no battery inside the charger. Make sure the battery is OK before placing it into the charger.

Removing cover to check battery

Placing a battery into the Jordan charger

Reading a dosimeter: Remove the cap on the charging socket by unscrewing the cap. Then press down lightly with the dosimeter on the charging socket. The light should come on.

When the charging pin is pressed firmly into the charging socket (receptacle) on the charger, the pin contacts the electrometer frame. Sufficient voltage is applied to charge up the dosimeter and to set the fiber to zero. The charger should be used to recharge the dosimeter to zero before each use of the instrument.

A. While pressing the charging end of the dosimeter firmly down in the receptacle of the charger, adjust the "down-scale/up-scale" control on the charger, while looking through the dosimeter at the light that comes on until a zero reading is indicated IF the fiber is not moving, press the dosimeter farther down in the receptacle and try again.

Here you see Ron "Zeroing" a dosimeter, notice his left hand on the adjustment knob.

After he has Zeroed the dosimeter, he lets up just a little to keep the light on and see if the fiber is still on zero.

B. At times, a transient "kick" is experienced when zeroing the dosimeter. The charging contact of the charger automatically compensates for the kick when the dosimeter is with drawn slowly from the contact. You can see this effect by holding the dosimeter on the charging contact while looking into the instrument. Withdraw the instrument slowly. You will note that just before the light turns off, the hairline will shift. With a little practice the hairline can be made to shift so that its final position coincides with the zero line. Optimum performance is obtained when electrostatic kick is compensated for in this manner. The hairline will remain on or near the zero position for long periods when not exposed to radiation.

C. When resetting the dosimeter to zero, the fiber may disappear and remain hidden. To release the fiber, slowly turn the "down scale / up scale" knob until the fiber reappears..

D. At the end of the designated period of exposure, the accumulated amount of radiation can be read directly from the scale by looking through the eye-piece while pointing the dosimeter towards an external light source.

Preventative Maintenance

The dosimeter is an extremely sensitive instrument and, although it has been constructed for rugged use, it should receive the same care as a wristwatch. Since these dosimeters are hermetically sealed at the factory, the instrument cannot be repaired or adjusted in the field. Therefore, if malfunctioning of an instrument is experienced, it should be returned to the factory. The dosimeters may be maintained in prescribed operating condition by simply cleaning the eye.lens and the charging switch diaphragm which clean water (DO NOT use any alcohol base products)and a cloth free of lint and grit. Extra care should be taken to make sure the charging switch diaphragm is absolutely free of lint, dirt, or moisture at all times.

Caution

Do not insert any sharp objects into or tamper with parts in the charging switch recess, as irreparable damage may be done to the instrument. Also, do not clean lenses or the charging switch with any solvent other than clean water as the plastic materials can be affected by many solvents.

Instructions on the use of zeroing (charging) the Direct Reading Pocket Dosimeter with the Jordan charger. Printable copy in PDF format