Vernier VRM-BTD User manual

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Videos
View videos related to this product at http://www.vernier.com/vrm-btd
Specifications
Sensor LND 712 (or equivalent) halogen-quenched GM tube
with a 1.5 to
2.0 mg/cm2mica end window
Gamma sensitivity 18 cps/mR/hr referenced to Co-60
Temperature range –20 to 50°C
Operating range CPS 0–3,500
Note: This sensor is equipped with circuitry that supports auto-ID. When used
with LabQuest 2, LabQuest, LabQuest Mini, LabPro, SensorDAQ, TI-Nspire™
Lab Cradle, or CBL 2™, the data-collection software identifies the sensor and
uses pre-defined parameters to configure an experiment appropriate to the
recognized sensor.
SuggestedExperiments
Counts/Interval vs. Distance Studies
The data in the two graphs below were collected by monitoring gamma radiation
at various distances from a Radiation Monitor. Data were collected with the run
intervals set at 100 seconds. After each 100-second interval, the source was moved
one centimeter further from the source. Since distance is proportional to time (300
seconds in the first graph corresponds to 3 cm in the second graph;
400 seconds to 4 cm, etc.), a new distance column was made using time divided
by 100. The curved fit shown corresponds to distance raised to the –2 power
(inverse squared).
Counts/interval vs. time and distance
Counts/Interval vs. Shielding Studies
The data shown here were collected by monitoring gamma radiation with an
increasing number of pieces of silver foil placed between the source and a
Radiation Monitor. Data was collected with the run interval set at 100 seconds.
After each 100-second interval, another piece of silver foil was placed between the
source and the Radiation Monitor. Since the number of pieces is proportional to
Vernier Radiation
Monitor
(Order Code VRM-BTD)
The Vernier Radiation Monitor is used to monitor
alpha, beta, and gamma radiation. It can be used with a
number of interfaces to measure the total number of counts per specified timing
interval.
Use this sensor to
lDetect the presence of a source of radiation.
lMonitor counts/interval (rate) as different thicknesses of a particular type of
shielding are placed between the Geiger-Mueller tube of the Radiation Monitor
and a beta or gamma source.
lCompare the effect of different types of materials to shield beta or gamma
radiation.
lSet up a histogram with a very long run time to show students how initial
randomness of data develops first in a Poisson distribution, and then into a
Gaussian distribution curve.
lMeasure radiation of common radioactive materials, such as lantern mantels or
pre-World War II Fiestaware.
lMonitor variation in background radiation at different elevations.
lMonitor radioactivity in the environment over long periods of time.
lMonitor counts per interval (rate) from a beta or gamma radiation source as a
function of the distance between the source and the Radiation Monitor.
Note: Vernier products are designed for educational use. Our products are not
designed nor are they recommended for any industrial, medical, or commercial
process such as life support, patient diagnosis, control of a manufacturing
process, or industrial testing of any kind.
Compatible Software
See www.vernier.com/manuals/vrm-btd for a list of software compatible with the
Radiation Monitor.
Getting Started
1. Connect the sensor to the interface (LabQuest Mini, LabQuest 2, etc.).
2. Start the appropriate data-collection software (Logger Pro, Logger Lite,
LabQuest App, or Graphical Analysis 4) if not already running, and choose
New from File menu. The software will identify the sensor and load a default
data-collection setup. You are now ready to collect data.
If you are collecting data using a Chromebook™, mobile device such as iPad®or
Android™ tablet, or a Vernier wireless interface, please see the following link for
up-to-date connection information:
www.vernier.com/start/vrm-btd

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Histogram Data Analysis
For an easy in-class experiment, set up a histogram with a very long run time and
start data collection. Whenever the graph overflows the top of the graph, it will be
rescaled. This data collection shows students how initial randomness of data
develops into a Gaussian distribution. A gamma radiation source was used.
A distribution graph
Lantern Mantles
This graph shows a study of old and new Coleman mantle lanterns. These mantles
formerly contained thorium and were often used for radiation demonstrations. In
the early 1990s, Coleman changed the production methods and now the mantles
are not radioactive. First, no mantle was near the monitor for ten minutes, then an
old mantle for ten minutes, and then a new, non-radioactive mantle for the last ten
minutes.
New and old lantern mantles
time (300 seconds corresponds to 3 pieces of foil, 400 seconds to 4 pieces of foil,
etc.), a new column, pieces of silver foil, was made using time divided by 100.
Counts/interval vs. thickness of filter
Half-Life Determination (Counts/Interval vs. Time)
Using a daughter isotope generator, it is possible to generate isotopes with a
relatively short half-life. A solution that selectively dissolves a short half-life
daughter isotope is passed through the generator. The linear plot of natural log of
decay rate vs. time can be used to determine the half-life of the daughter isotope,
using the formula
ln 2 = λt½
where λ is the decay rate constant and t½is the half-life of the daughter isotope (in
minutes).
In the plot of natural log of decay rate vs. time, the decay rate constant, λ, is equal
to –m. Using the slope value of m= –0.217 in the example here, the
half-life was calculated to be 3.19 minutes.
Half-life determination

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Care and Maintenance
Do not insert anything through the screen at the tip of the sensor. The surface is
very fragile.
Do not wrap the cable tightly around the sensor for storage. Repeatedly doing so
can irreparably damage the wires and is not covered under warranty.
How the Sensor Works
The Radiation Monitor senses ionizing radiation by means of a Geiger-Mueller
(GM) tube. The tube is fully enclosed inside the instrument. When ionizing
radiation or a particle strikes the tube, it is sensed electronically and monitored by
a computer and by a flashing count light. There is an optional audio signal.
Radiation is measured in counts in a time interval, as configured in data-collection
software. About 5 to 25 counts at random intervals (depending on location and
altitude) can be expected every minute from naturally occurring background
radiation. The flashing count light will always flash when an event is detected. To
enable or disable the audio signal, use the switch on the side of the unit.
The end of the GM tube has a thin mica window. This mica window is protected
by the screen at the end of the sensor. It allows alpha particles to reach the GM
tube and be detected. The mica window will also sense low energy beta particles
and gamma radiation that cannot penetrate the plastic case or the side of the tube.
Note: Some very low energy radiation cannot be detected through the mica
window. The tube is fragile and physical damage to the window is not covered by
the warranty.
Note: Since the software must count pulses for one data-collection interval before
reporting a value, a reading will never be shown at t= 0.
Further Tips for Monitoring Radiation
To measure gamma and X-rays, hold the tip of the Radiation Monitor toward the
source of radiation. Low-energy gamma radiation (10–40 KeV) cannot penetrate
the side of the GM tube, but may be detected through the end window.
To detect alpha radiation, position the monitor so the suspected source of radiation
is next to the GM window. Alpha radiation will not travel far through air, so put
the source as close as possible (within 1/4 inch) to the screen without touching it.
Even a humid day can limit the already short distance an alpha particle can travel.
To detect beta radiation, point the end window toward the source of radiation.
Beta radiation has a longer range through air than alpha particles, but can usually
be shielded (e.g., by a few millimeters of aluminum). High energy beta particles
may be monitored through the back of the case.
To determine whether radiation is alpha, beta, or gamma, hold the tip of the
monitor toward the specimen. If there is an indication of radioactivity, it is most
likely gamma or high energy beta. Place a piece of aluminum about 3 mm (1/8")
thick between the case and the specimen. If the indication stops, the radiation is
most likely beta. (To some degree, most common radioactive isotopes emit both
Background Radiation
Here is an experiment performed in the days before airlines insisted that you turn
off your personal computer before takeoff. It shows the counts/interval between
takeoff and the time the plane reached its cruising altitude of 39,000 ft.
Radiation during an airline flight
Curricular Materials
Nuclear Radiation with Vernier
by John Gastineau
This book has six experiments written for the Vernier Radiation Monitor. Each of
the six experiments has a computer version (for LabPro, LabQuest, or LabQuest
Mini), a calculator version (for LabPro or CBL 2™), and a LabQuest version (for
LabQuest 2 or the original LabQuest as a standalone device). The electronic
resources for Nuclear Radiation with Vernier contain the word-processing files for
all student experiments.
Radioactive Sources
If you do not have radiation sources, you may be able to obtain pre-1990 Coleman
lantern mantles or other brands of lantern mantles (for a weak source of Thorium).
You may also be able to find pottery, watches, clocks, or minerals that are
moderately radioactive. Vaseline glass and red-orange Fiestaware plates made
prior to 1943 can be found in antique stores.
For something more active, order radioactive minerals from these scientific supply
houses. The
2.5 cm disk sources of alpha, beta and gamma radiation are particularly
convenient.
Flinn Scientific Inc.
P.O. Box 219
Batavia, IL 60510
Phone [phone]
www.flinnsci.com
Spectrum Techniques
106 Union Valley Road
Oak Ridge, TN 37830
Phone [phone]
www.spectrumtechniques.com

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The user assumes all risk and liability connected with such use. Vernier is not
responsible for incidental or consequential damages arising from the use of this
instrument.
Disposal
When disposing of this electronic product, do not treat it as household waste. Its
disposal is subject to regulations that vary by country and region. This item should
be given to an applicable collection point for the recycling of electrical and
electronic equipment. By ensuring that this product is disposed of correctly, you
help prevent potential negative consequences on human health or on the
environment. The recycling of materials will help to conserve natural resources.
For more detailed information about recycling this product, contact your local city
office or your disposal service.
The symbol, shown here, indicates that this product must not be disposed of in
a standard waste container.
Vernier Software & Technology
13979 SW Millikan Way • Beaverton, OR 97005-2886
Toll Free [phone] • [phone] • Fax [phone]
[email protected] • www.vernier.com
Rev. 08/20/19
Logger Pro, Logger Lite, Graphical Analysis, Vernier LabQuest, Vernier LabQuest Mini, and other marks shown are
our trademarks or registered trademarks in the United States.
iPad is a trademark of Apple Inc., registered in the U.S. and other countries.
All other marks not owned by us that appear herein are the property of their respective owners, who may or may not
be affiliated with, connected to, or sponsored by us.
beta and gamma radiation.) If there is no indication through the back of the case,
position the end window close to, but not touching, the specimen. If there is an
indication, it is probably alpha or beta. If a sheet of paper is placed between the
window, and the indication stops, the radiation is most likely alpha. In order to
avoid particles falling into the instrument, do not hold the specimen directly above
the end window.
The Radiation Monitor does not detect neutron, microwave, radio frequency (RF),
laser, infrared, or ultraviolet radiation. Some isotopes it will detect relatively well
are cesium-137, cobalt-60, technicium-99m, phosphorus-32, and strontium-90.
Some types of radiation are very difficult or impossible for this GM tube to detect.
Beta emissions from tritium are too weak to detect using the Radiation Monitor.
Americium-241, used in some smoke detectors, can overexcite the GM tube and
give an indication of a higher level of radiation than is actually there.
Troubleshooting
For troubleshooting and FAQs, see www.vernier.com/til/3207
Repair Information
If you have watched the related product video(s), followed the troubleshooting
steps, and are still having trouble with your Radiation Monitor, contact Vernier
Technical Support at [email protected] or call 888-837-6437. Support
specialists will work with you to determine if the unit needs to be sent in for
repair. At that time, a Return Merchandise Authorization (RMA) number will be
issued and instructions will be communicated on how to return the unit for repair.
Warranty
This product is warranted to the original owner to be free from defects in materials
and workmanship for five years from the date of purchase. The Geiger-Mueller
tube is covered by a one-year warranty.
Vernier will, at its own discretion, repair or replace this instrument if it fails to
operate properly within this warranty period unless the warranty has been voided
by any of the following circumstances: misuse, abuse, or neglect of this instrument
voids this warranty; modification or repair of this instrument by anyone other than
Vernier voids this warranty; contamination of this instrument with radioactive
materials voids this warranty. Contaminated instruments will not be accepted for
servicing at our repair facility.
The GM tube has a finite life span, and it is normal that it must be replaced after a
few years, although some tubes last much longer. Tubes that fail within a year of
purchase will be replaced under warranty. Tubes that fail after a year will be
replaced for a fixed fee of $89. The GM tube is fragile and physical damage to the
entrance window is not covered by warranty. Tubes that are punctured will not be
replaced under warranty. The user is responsible for determining the suitability of
this product for his or her intended application.