Microsoft word - ap1884-001+002.doc

INSTRUCTION SHEET
GEIGER COUNTER / RATE - digital - hand held
Cat: AP1884-001 with internal GM tube
AP1884-002 for external GM tube.
DESCRIPTION:
This unique fully portable battery operated instrument is used: • To detect and count high energy Alpha particles, Beta particles and Gamma rays• To count either continuously or over preset periods of 10 sec, 60 sec or 100 sec.
• To measure Rate of counts per second or Rate of counts per minute.
Model AP1884-001 is complete with an internal Geiger Muller (GM) tube which makes itideal for industry, the classroom or for outdoors. The thin mica window of the tube isprotected against mechanical damage by a plastic grille.
Model AP 1884-002 is complete with a socket to accept a remote GM tube to be connectedto the instrument by cable. The IEC Tube Holder and Leads (PA1885-050) as supplied onearlier models are fully compatible.
AP1884-001 internal GM tube AP1884-002 external GM tube
Maximum geiger counting rate is 10kHz. and an audible 'click' for each particle count may beenabled or disabled by press button.
The IEC Geiger Counter & Rate meter will run on 3x standard 'AA' (penlight) batteries for aperiod of about 100 hours. Alkaline cells will give an even longer operating life. Whenbatteries are approaching the flat condition, 'bAtt' displays momentarily without disturbingcounting operations. If the batteries flatten, a socket is provided in the end of theinstrument for any normal 240/12V.AC or DC Plug Pack. Polarity is not important.
I N D U S T R I A L E Q U I P M E N T & C O N T R O L P T Y . L T D .
6 1 - 6 5 M c C l u r e S t . T h o r n b u r y . 3 0 7 1 M e l b o u r n e . A u s t r a l i a T e l : 6 1 ( 0 ) 3 9 4 9 7 2 5 5 5 F a x : 6 1 ( 0 ) 3 9 4 9 7 2 1 6 6 a p 1 8 8 4 - 0 0 1 + 0 0 2 . d o c 6 - A p r - 1 1 INSTRUCTION SHEET
The high voltage for the GM tube is fully adjustable from 300 to 500V.DC. by pressing theVOLTS and ARROW buttons simultaneously when in ‘Standby’ (display flashing). Thevoltage is displayed for checking. Different Plateau Voltages may be set from time to timefor various experiments and the set voltage is automatically restored on each power-up.
Instrument Size: 195x100x37mm LxWxH Weight: 0.42 kg
Power: 240/12V.AC. PlugPak (not supplied) permits unlimited operation time.
Internal battery: (3x ‘AA’ cells supplied) permits approx. 100 hours counting time.
Auto Power Down: The instrument has no "Off" switch. To conserve battery life, if the
instrument is performing a count or is in ‘Standby’ mode, the instrument will automatically
power down after 4 minutes. If it is actively counting in the Count / Continuous' mode, the
instrument will not power down.
In any mode or in ‘Standby’ (display flashing), if any of the 5 buttons is pressed, theoperating period is extended by another 4 minutes. When re-powered, the previous Modeis restored and the last reading is displayed.
Brief Information:
A label on the rear of the housing provides the user with all the important informationrequired to operate the instrument properly.
Functions of the 5 press buttons:
ON / VOLTS: has two functions
• Powers the instrument after an automatic power down. The display self checks and the previous mode is restored and the last reading is displayed.
• Displays the current GM tube plateau voltage if pressed while the display is flashing SOUND ON / OFF: Enables and disables the audible 'click' during counting.
STOP / HOLD: In any mode, this button stops the counting and holds the last count in the
display. Sets the ‘Standby’ mode and the display flashes.
START / DOWN ARROW: has two functions
1) Resets display to zero and starts any selected function.
2) Lowers the Plateau voltage to the tube if pressed whilst the ON / VOLTS button is helddepressed when in ‘Standby’.
I N D U S T R I A L E Q U I P M E N T & C O N T R O L P T Y . L T D .
6 1 - 6 5 M c C l u r e S t . T h o r n b u r y . 3 0 7 1 M e l b o u r n e . A u s t r a l i a T e l : 6 1 ( 0 ) 3 9 4 9 7 2 5 5 5 F a x : 6 1 ( 0 ) 3 9 4 9 7 2 1 6 6 a p 1 8 8 4 - 0 0 1 + 0 0 2 . d o c 6 - A p r - 1 1 INSTRUCTION SHEET
MODE / UP ARROW: has two functions
1) When the instrument is in ‘Standby’ (display flashing), this button provides selection ofthe six different operational modes. The first press displays the current mode operating: DISPLAY SHOWS
(updates each second and calculates average/minute) Cntr : Cont (auto power down is disabled) After the desired mode is selected, the START button must be pressed to zero the displayand to initiate the counting.
2) Raises the Plateau voltage to the tube if pressed whilst the ON / VOLTS button is helddepressed when in standby.
Battery Replacement: This instrument is supplied with batteries which must be
fitted. For best performance, use only good quality batteries. To install or to change
batteries, remove the two screws and remove the lower end plastic cover. Partly slide out
the front panel and replace the three ‘AA’ dry cells. To reset the system, momentarily press
the mini press button near the battery holder and replace the plastic end cover. When the
batteries are replaced, the GM tube voltage is always automatically set to 450V.DC. as the
normal operating voltage. To adjust it to a different plateau voltage, refer to information on
the UP / DOWN ARROW buttons above.
Parts & accessories:
PA1885-030 Tube Holder, cable & BNC plug (without tube)
PA1885-050 Tube Holder, cable & BNC plug including GM tube
PA1885-020 Spare GM tube only. Warranty is void unless fitted and tested by IEC.
NOTE: Because of the fragile nature of thin mica window tubes, IEC cannot provide
warranty on GM tubes unless IEC fits the tube to the holder and performs operation tests.
LB1885-100 GM tube support device for bench experiments. Holds the GM tube to match
the IEC Radiation Absorber support / holder (Cat: PA0031-001)
AP0030-001 Absorber set. 24x calibrated absorbers from tissue paper, foil, aluminium
sheet through to thick lead. With absorber and R/A source holder for radiation study.
Designed and manufactured in Australia
I N D U S T R I A L E Q U I P M E N T & C O N T R O L P T Y . L T D .
6 1 - 6 5 M c C l u r e S t . T h o r n b u r y . 3 0 7 1 M e l b o u r n e . A u s t r a l i a T e l : 6 1 ( 0 ) 3 9 4 9 7 2 5 5 5 F a x : 6 1 ( 0 ) 3 9 4 9 7 2 1 6 6 a p 1 8 8 4 - 0 0 1 + 0 0 2 . d o c 6 - A p r - 1 1 INSTRUCTION SHEET
MORE INFORMATION ON GEIGER COUNTING:
A Geiger Counter is a device that responds to radioactive particles or rays entering a specialchamber called a Geiger Muller tube. There are several other types of counting tubes.
The GM tube used in the IEC Geiger Counter has an internal electrode and a very thinwindow of Mica sealed across the front end of the tube, Mica is a mineral insulating mineralthat can be split into very thin layers. The window is very fragile and must not be touched.
If ruptured, the tube becomes useless. A plastic grille is placed over the front of the tubebut, so that Alpha particles can reach the window, but it is not a complete cover so neverpermit poking of anything down the grille or the tube window will be ruptured.
Radioactive rays and particles enter the chamber and these create small electric dischargesthat are counted. Beta and Gamma radiation passes freely through the Mica window butonly the higher energy Alpha particles can penetrate the thin Mica.
The number of counts received and their meaning depends of the following factors: • Size of the GM tube’s front window. A large window will have a much larger area and of course it will accept much more radiation.
• Distance away from the Radio Active source. The count varies as the square of the distance away from the source. If you double your distance away, the counts will beabout a quarter. For example …. If a small “school grade R/A source” is placed ametre from the instrument, the count rate per minute will rise by a small amount. Ifthe same source is placed up against the tube so all the radiation enters the tube,the count can be hundreds or thousands of counts per second.
• Type of activity being radiated. Alpha particles are considered to be 20 times more dangerous to the human tissue that the others, therefore the type of radiation shouldbe known before “danger levels” can be estimated.
• Strength of the source radiating. Strong sources emanate more particles per sec.
It is then obvious that although the number of counts per second or per minute or over anyset period is an indication of the activity in your immediate surroundings, the number doesnot advise you of the intensity or the “danger level” or the radiation. The count andparticularly the rate of counts is very useful to be used as a comparison between strengthsof radiation and, in many cases, this comparison is enough to estimate safety.
However, for the count to indicate an absolute “strength of radiation” or “danger level” to theuser, the instrument would need to be calibrated against a special standard with all thefactors applied (Q factor) and this calibration must be checked and certified regularly. TheIEC “Geiger Counter and Rate Meter” is not designed for this purpose.
Alpha radiation: Consists of particles consisting of 2x protons and 2x neutrons which are
identical to the nucleus of the Helium atom …. but without the electrons. Very damaging to
human tissue but are very easy to block. Most Alpha cannot penetrate the GM tube window.
Beta radiation: Consists of very high speed particles which are identical to electrons and
which come from the nucleus of an atom. Penetrate many materials but can be blocked.
Gamma radiation: Consists of electromagnetic rays or photons that are emitted from the
nucleus of an atom. Deeply penetrating and difficult to completely block or absorb.
I N D U S T R I A L E Q U I P M E N T & C O N T R O L P T Y . L T D .
6 1 - 6 5 M c C l u r e S t . T h o r n b u r y . 3 0 7 1 M e l b o u r n e . A u s t r a l i a T e l : 6 1 ( 0 ) 3 9 4 9 7 2 5 5 5 F a x : 6 1 ( 0 ) 3 9 4 9 7 2 1 6 6 a p 1 8 8 4 - 0 0 1 + 0 0 2 . d o c 6 - A p r - 1 1 INSTRUCTION SHEET
THE MEANING OF “HALF-LIFE”…… When talking about radioactivity, we often hear theterm “half-life”. If a radioactive source has a half-life of say 100 years, it means that after100 years, its activity will be reduced to half of what it was at year 1. In a further 100 years,it would be reduced to be half of what it was in year 100 …. and so on and on.
Their activity eventually approaches zero but the radiation can be very dangerous to humansfor a very long time. Some sources have half-lives of seconds or hours or days and otherscan have half-lives of thousands of years. This is why some strongly radioactive materialspresent us with a huge problem in storing it away from living creatures.
INFORMATION ON THE UNITS USED FOR RADIATION:
Roentgen: This is the measurement of “exposure” or the ionisations of the molecules ofa mass of dry air. Is used only for “X”rays and Gamma. Not used for general purposes.
Curie (Ci): This is the quantity of a radioactive material that will have 37,000,000,000transformations in one second. A more common unit is mCi millicurie or uCi microcurieor nCi nanocurie.
Rad: (abbreviation for Radiation Absorbed Dose). This is the unit for the absorbedenergy into a mass. Defined as: 100 ergs of energy absorbed per gram of material Rem: (abbreviation for Roentgen Equivalent Man). This is the unit for “equivalent dose”with factors applied to relate directly to the human biology. To get ‘Rem’, the value ‘Rad’ ismultiplied by a factor ‘Q’ that is unique to the radiation being emitted, whether Alpha, Betaor gamma or combination.
Becquerel (Bq): This is the activity of the source at 1 transformation per second …there are therefore 3.7 x1010 Bq in one Curie. It is a very small unit and kBqkilobecquerels or MBq magabecquerels or GBq gigabecquerels are more often used.
Gray (Gy): This is the radiation that the cells of any material are absorbing. It is 1xJoule of energy absorbed into 1x kg of mass of a material. This is similar to the ‘Rad’ unitbut the ratio is Ix Gray = 100 ‘Rads’. Often expressed as centi-grays (hundredths of aGray). It can be called the “absorbed dose”.
Sievert (Sv): This is the “dose equivalent” which relates the “absorbed dose”specifically to the biology of the human body. The absorbed dose (the Gray) is multipliedby a special dose factor “Q” that is unique to the type of radiation emanating. This unitSievert is similar to the ‘Rem’ except that the ratio is 1x Sievert = 100 ‘Rem’. Oftenexpressed in millionths of a Sievert or micro-sievert.
A USEFUL DESCRIPTION TO BETTER UNDERSTAND THE UNITS: If you are in a rainstorm, you can consider that the unit for the total amount of rainfalling as ‘Becquerels’. The amount of rain falling on you would be as ‘Grays’ andhow wet you are getting would be as ‘Sieverts’.
I N D U S T R I A L E Q U I P M E N T & C O N T R O L P T Y . L T D .
6 1 - 6 5 M c C l u r e S t . T h o r n b u r y . 3 0 7 1 M e l b o u r n e . A u s t r a l i a T e l : 6 1 ( 0 ) 3 9 4 9 7 2 5 5 5 F a x : 6 1 ( 0 ) 3 9 4 9 7 2 1 6 6 a p 1 8 8 4 - 0 0 1 + 0 0 2 . d o c 6 - A p r - 1 1

Source: http://www.iecpl.com.au/z_pdfs/ap1884-001+002.pdf