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Topic: Liquid scintillation counting


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In the News (Sun 23 Jun 19)

  
  Scintillator - Wikipedia, the free encyclopedia
Scintillators are defined by their short fluorescence decay times and optical transparency at wavelengths of their own specific emission energy, characteristics which set them apart from phosphors.
However, many materials scintillate at some level; scintillation of atmospheric nitrogen is used by some high-energy astrophysics experiments, and scintillation of liquid xenon and neon plays a role in some ultra-low-background experiments.
However, organic liquid scintillating fluids are well-suited for detecting very low energy particle radiation such as beta radiation from tritium by simply immersing the sample to be tested in the scintillation fluid, thereby negating detector absorption problems due to the very short mean free paths associated with low energy particles.
en.wikipedia.org /wiki/Scintillator   (412 words)

  
 Liquid scintillation counting - Wikipedia, the free encyclopedia
Liquid scintillation counting is a standard laboratory method in the life-sciences for measuring radiation from beta-emitting nuclides.
Scintillating materials are also used in differently constructed "counters" in many other fields.
Counting efficiencies under ideal conditions range from about 30% for Tritium (a low-energy beta emitter) to nearly 100% for Phosphorus-32, a high-energy beta emitter.
en.wikipedia.org /wiki/Liquid_scintillation_counting   (367 words)

  
 Radiation Safety Guide
Due to low disposal costs for liquid scintillation counting wastes and the complexities of the DIS procedures, all liquid scintillation counting wastes, regardless of the contaminating isotope, are picked up and disposed of by the waste disposal service vendor.
Liquid scintillation wastes (including wastes contaminated with short-lived isotopes) are transported for disposal by the University's radioactive waste disposal services broker.
The primary disposal of liquids to the sanitary sewer is defined as the disposal of radioactive liquids under conditions which do not meet the criteria for "secondary disposals," i.e., the disposal of quantities in excess of the limits in paragraph 15.D.2.b.(2) or the disposal of relatively high concentrations, regardless of activity.
webware.princeton.edu /sites/ehs/radsafeguide/rsg_sec_15.htm   (2425 words)

  
 [No title]
The scintillator (usually phosphor molecules) in question emits these photons by absorbing the energy of the excited primary scintillator in which the radioactive sample have been dissolved, which then returns to their normal level of energy.
Counts are lost from the upper to the lower energy channel so by measuring two channels, the counts lost in the high energy channel will be detected in the lower energy channel.
The liquid scintillation counting technique and radioisotope marking, which have been developed in the early fifties, have a wide variety of uses, particularly in clinical laboratories.
www3.sympatico.ca /teknoman.fmcc/lab/2/intro.doc   (546 words)

  
 LSC 94 Abstracts
We used a Packard Tri-Carb® 460C liquid scintillation counter upgraded with an anticoincidence shield and circuitry to study the relation between the background of the counter and the cosmic-ray intensity.
For measuring alpha radioactivity in water samples by liquid scintillation counting (LSC), the volume of water sample to be analyzed depends on the loading capacity of the LS cocktail, typically up to 40% of the total counting volume.
Alpha/beta separation efficiency by liquid scintillation counting (LSC), as defined by the percent misclassification at the optimum pulse decay discriminator (PDD) setting, is influenced by the relative pulse shapes of alpha and beta events produced at the photomultiplier tube (PMT) anode.
www.radiocarbon.org /Pubs/LSC94/abstracts.html   (8134 words)

  
 SAHRA - Isotopes
Decay counting methods are used to determine the activity or concentration of radioactive isotopes.
Liquid scintillation counting (LSC) may also be used to detect alpha and beta emitters, and is more effective than gas proportional counting systems in detecting beta particles, which have limited penetrating ability.
LSC involves dissolving a sample in a solvent or sequence of solvents (usually benzene or toluene), which act as scintillators, or materials that flouresce when struck by a charged particle or high-energy photon.
www.sahra.arizona.edu /programs/isotopes/methods/decay.html   (267 words)

  
 U of T Lab Hazardous Waste Manual   (Site not responding. Last check: 2007-11-03)
Liquids (except concentrated sodium hydroxide or potassium hydroxide solutions) containing radioactive material must be poured into plastic bottles containing absorbent material which are provided by EHS for the collection of radioactive liquid waste.
Any aqueous liquid waste meeting the criteria in Column E in Table 2 may be disposed to the regular drain, followed by several litres of running water to ensure that the sink trap is flushed completely.
If a liquid scintillation counter is to be sent for disposal, the Senior Radiation Safety Officer must be notified in writing to arrange for the deletion of the counter from the associated Permit.
www.utoronto.ca /safety/Waste/wm5_3.htm   (2093 words)

  
 Radioactivity Analysis
This source is counted for alpha, beta, or gamma using alpha spectrometry, gas proportional counting, liquid scintillation counting, or gamma spectroscopy.
The preparation of a counting source for alpha spectrometry is one of the most critical steps in the radiochemical analysis of environmental samples, waste effluents, uranium tailings, spent fuel, etc. for long-lived emitters.
Liquid scintillation counting is a method for the detection of both alpha and beta emitters which has been widely applied in the fields of biological research, dating, health physics, particle physics, and radiochemistry.
www.cartage.org.lb /en/themes/Sciences/Chemistry/Analyticalchemistry/MethodsInstrumentation/RadioactivityAnalysis/RadioactivityAnalysis.htm   (568 words)

  
 Radiation Safety Manual
Liquid scintillation counting is the preferred method for detecting H-3.
Liquid scintillation counting is the preferred method for detecting C-14.
Liquid scintillation counting is the preferred method for detecting Fe-55 contamination, although a low energy sodium iodide crystal scintillation detector will also detect Fe-55 with a lower efficiency.
web.princeton.edu /sites/ehs/radmanual/radman_app_b.htm   (3860 words)

  
 IN/US Sample Detection Cells   (Site not responding. Last check: 2007-11-03)
For liquid scintillation counting there are micro cells with active volumes starting at 2 µl and with dead volumes of 1 µl or less.
H counting efficiency is always low, they require lengthy dark adaptation to reach their lowest backgrounds which are never as low as with liquid scintillator, double isotope counting is not really possible, and replacement costs are relatively high.
Scintillating glass is at the same time the solid scintillator least easily contaminated, the most rugged of them, and can withstand the most rigorous of decontamination procedures.
www.inus.com /docs/cell.htm   (1929 words)

  
 Millipore - Technical Library - MultiScreen Methods: Efficient Low-Energy Radioisotope Detection in Vial-based Liquid ...
However, their low level of energy can cause difficulties in liquid scintillation counting when samples are collected on any solid support, including a microporous membrane.
The sample counts (n=8) represent the punched HV filter with collected trichloroacetic acid (TCA) precipitate added to 500 µL water, mixed for 30 minutes, and followed by the addition of 5 mL cocktail.
The five LSC solutions in Table 2 were evaluated for general counting efficiency in detecting tritium radiation with the MultiScreen system.
www.millipore.com /publications.nsf/86714eb8c10dcec485256b3c005a8bd7/b09c294f43e9060485256f9a005a9cba?OpenDocument   (2037 words)

  
 Liquid Scintillation Counting
The next development in counting technology was the conversion of sample carbon to CO gas for measurement in Gas Proportional counters.
The essential electronic components of the Liquid Scintillation (LS) Spectrometer according to Gupta and Polach (1985), are photo multiplier tubes (PMTs), high voltage supply, signal preamplifiers, pulse and summing amplifiers, coincidence logic, timer and scaler (Gupta and Polach, 1985:50).
One of the major advantages of LSC is that sample, background and modern vials are able to be rotated into the counting chamber by the operator.
www.c14dating.com /lsc.html   (1897 words)

  
 ISU Environmental Monitoring Program
Samples are counted for ten 20-minute periods in a Wallac model 1415 liquid scintillation counter and the average count rate (counts per minute) determined.
Count rate is converted to activity concentration through calibration with standards traceable to the National Institute of Standards and Technology (NIST).
The performance checks consist of both background and check source counts for the proportional and liquid scintillation counters and check source counts and full width at half maximum determinations for the gamma spectrometers.
www.physics.isu.edu /health-physics/eml.html   (866 words)

  
 Radiation Safety Manual
These factors include: half-life, radionuclide, chemical constituents, physical form (liquid or solid), dose rate, and other physical characteristics (is the source sealed and encapsulated or open?).
All liquid scintillation wastes are disposed of through a contracted radioactive waste disposal services broker as part of the Off-Site Radioactive Waste Disposal Program managed by EHS.
All LSC wastes, regardless of the isotope, are disposed of through an off-site disposal program.
webware.princeton.edu /sites/ehs/radmanual/radman_sec_7.htm   (572 words)

  
 Liquid scintillation counting
Please refer to Ask the Expert Question/Answer 666 for a discussion of liquid scintillation counting.
Those standards and blanks will also provide the necessary efficiency and background count data to determine disintegrations per unit time per wipe area (for example, dpm/100 cm square) for comparison to acceptable regulatory standards.
Textbook references on radiation detection and measurement and, in particular, count statistics are also provided in Ask the Expert Question/Answer 807.
www.hps.org /publicinformation/ate/q1591.html   (531 words)

  
 Measurements/Calculations
This technique involves dissolving the sample containing a radionuclide in a suitable scintillation solution and the use of a liquid scintillation counter.
When there is sufficient mass of a radiolabeled compound for a small sample to be accurately weighed and counted by liquid scintillation counting, the specific activity is expressed as (e.g.) µCi/mg.
If the specific activity is greater than 1 Ci/mmol, the specific activity may be calculated by relating the radioactive concentration (determined by liquid scintillation counting) to the chemical concentration, and then converting the figure obtained to Ci/mmol (Bq/mmol).
www.sigmaaldrich.com /Area_of_Interest/Biochemicals/Radiochemicals/Key_Resources/Measurements_Calculations.html   (780 words)

  
 [No title]   (Site not responding. Last check: 2007-11-03)
In: LSC 2001, Advances in liquid scintillation spectrometry, 41-44, 2003.
A simple and sensitive liquid scintillation counting system for continuous monitoring of radon in water.
In: LSC 2001, Advances in liquid scintillation spectrometry, 249-252, 2003.
www.raunvis.hi.is /~pth/publication.html   (376 words)

  
 liquid_scintillation
particles interact with scintillation system to produce small light flashes which are detected by photomultiplier tube and recorded as counts.
In general the more counts registered the more accurate is the number.
A sample with 100 cpm is counted for 10 min.
www.scar.utoronto.ca /~gurd/BgyC23/liquid_scintillation.html   (481 words)

  
 THE ECONOMICS OF RADIO FLOW-THROUGH MEASUREMENT   (Site not responding. Last check: 2007-11-03)
The newer alternative is the flow-through monitor, a modified form of the scintillation counter in which real-time measurement is made and results are analyzed on the fly.
For flow calculations with liquid scintillator, we've priced the solution at $150/4 liters, at the higher end of the commercial scale and suggest its use at a 3:1 scintillator:mobbil phase ratio.
  In the case of liquid scintillation counting, assuming that the HPLC eluate flows directly into a counting vial in a fraction collector, it is still necessary that scintillator solution be dispensed, the vial capped and shaken, the scintillation counter be loaded, and later unloaded and the vials disposed.
www.inus.com /docs/eco.htm   (1413 words)

  
 Radiological Services Information
Measurements are made on state-of-the-art liquid scintillation counter and are traceable to NIST (formerly NBS) standards.
Area wipes are analyzed by liquid scintillation counting.
Known or unknown isotope analysis of samples by liquid scintillation counting, gamma ray spectroscopy, or gas proportional counting.
www.tracer-tech.com /radio.html   (236 words)

  
 Liquid Scintillation Counters   (Site not responding. Last check: 2007-11-03)
Liquid scintillation counting is used mainly to detect low energy beta emitters.
The scintillator is a solution of organic or aqueous compounds into which the sample to be analysed is mixed.
Glass or transparent plastic vials are used for the scintillator so that the light can reach the photomultiplier tubes of the counting system.
www.triumf.ca /safety/rpt/rpt_6/node25.html   (79 words)

  
 NanoMed Product 4   (Site not responding. Last check: 2007-11-03)
Biomedical and chemical researchers routinely and universally employ liquid scintillation counting as a means of quantifying the amount of radioactivity emitted by beta-particle emitting isotopes (e.g., 3H and 14C) in samples generated during experiments.
the large quantities of “mixed” radioactive and organic waste generated by liquid scintillation counting presents an economical and environmental challenge.
The overall market for organic liquid scintillation cocktails is estimated at $60 million.
www.nanomedpharm.com /prod04.htm   (202 words)

  
 :: Hidex Ltd. - personal life science ::
It is a small, manual single-well instrument that performs liquid scintillation counting, gamma counting and luminescence counting.
Due to Triathler's extremely small size and light weight the counting is easy to perform in the field, wherever you collect your samples.
Close the counting head cap, turn it to the measurement position, and press a selection key to start.
www.hidex.com /?a=4&b=12&c=12   (122 words)

  
 Application of a Combined Procedure to the Determination of Residual Pu, Am and Sr in the Terrestrial Environment at ...
Strontium-90 was measured by liquid-scintillation counting after radiochemical separation using the double energy windows method.
Pu was measured by liquid-scintillation counting using the same plutonium source prepared for a-spectrometry analysis.
Sr, the major contributors were those associated with the counting statistics, especially the count rate and background rates in the
www.lanl.gov /BAER-Conference/BAERCon-46p012.htm   (514 words)

  
 INCT Home Page   (Site not responding. Last check: 2007-11-03)
Ra activities were measured after extraction of radon from 10 ml water samples to 10 ml of an Ultima Gold F scintillation cocktail directly in 22 ml scintillation vials.
The samples were counted in a new generation portable liquid scintillation counter, Betascout, without separation of the phases over the period of 30 days after extraction.
The discs were immersed in 10 ml of the scintillator and their activity was measured also by the same method.
www.ichtj.waw.pl /ichtj/nukleon/back/abstract/vol49_2004/v49n1p001.htm   (256 words)

  
 BioProtocol: Biotechnology Pharmaceutical Laboratory Research Protocols - Biotech, Pharma, Biomedical, Life Science
These solutions are easy-to-make liquid scintillants for liquid scintillation counting.
In addition to the recipes for making the liquid scintillants, this protocol describes two general methods for determining the radioactivity in organic and aqueous solutions.
Consult the instructions for your scintillation counter to determine the volume of Scintillation Fluid required to obtain accurate readings.
www.bio.com /protocolstools/protocol.jhtml?id=p109   (158 words)

  
 Detection equipment   (Site not responding. Last check: 2007-11-03)
However, when isotopes need to be identified and their concentrations established, gamma spectrometry or radiochemical analysis followed by alpha spectrometry or liquid scintillation counting may be required.
Liquid Scintillation Counting: low background levels with counting efficiencies ranging from 30 to 400%.
This instrument is used for total alpha and beta activity concentration (TAC and TBC) and for the determination of tritium, radium-226, radon-222 and strontium-90.
www.nrl.moh.govt.nz /Detectionequipment.html   (255 words)

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