PerkinElmer Tri-Carb LSA Investigator Guide

Liquid Scintillation Counting at any level using patented TR-LSC Technology

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Time Resolved Liquid ScintillationCounting (TR-LSC)

PerkinElmer Advances Liquid ScintillationCounting to a New Dimension!

Traditional liquid scintillation counting (LSC), usescoincidence counting to distinguish background eventsfrom true scintillation events. While this technologysuccessfully eliminates much of the background countsdue to electronic noise, it does not totally eliminateinstrument background arising from cosmic interac-tions with the glass face of the PMT or counting vial.This cosmic component and noise can cause up to 70%of the remaining background counts. PerkinElmer’s Tri-Carb® LSA uses a combination of coincidencecounting and a patented technology named time-resolved liquid scintillation counting (TR-LSC®) todistinguish true decay events from background. LSCsensitivity is a function of sample counting efficiencyand background. Higher efficiency and lower back-grounds dramatically increase counting sensitivity.TR-LSC technology reduces background by as much as90%, thereby greatly increasing sensitivity for all LSCapplications.

Why is TR-LSC Superior to ConventionalLiquid Scintillation Counting?

The characteristics of beta scintillation pulses andbackground radiation pulses are substantially different.Both consist of a prompt or fast component, but a back-ground pulse is followed by a series of low intensityafterpulses up to 5 µs after the prompt pulse.

TR-LSC adds a third dimension, called the pulse index,to liquid scintillation. The pulse index is a measure,over time, of the afterpulses associated with background.With this 3-D spectral analysis (see center plot below),TR-LSC distinguishes true beta decay from backgroundevents, leading to increased sensitivity and superiorcounting performance.

Furthermore, TR-LSC is programmable to optimizecounting any beta emitter in any cocktail. TR-LSCafterpulse discrimination is adjustable to accommodatethe delayed component that often accompanies higherenergy beta scintillation pulses to prevent this delayedcomponent from being misclassified as background.The programmable feature of TR-LSC minimizes themisclassification of the beta activity as background,resulting in higher counting sensitivity for higher energy beta emitters such as 90Sr/90Y.

In this comparison of a true beta decay eventversus a background event, both containprompt or fast pulses. Unlike true events,background prompt pulses are followed byafterpulses for as long as 5 µs. True decayevents can have a delayed or slow componentfor up to 900 ns, but do not have the distin-guishing afterpulses.

Three dimensional plots of pulse heightspectra. The pulse index is the thirddimension (z). TR-LSC uses the pulseindex of each scintillation event as oneof the criteria to reduce background.

Illustration of programmable TR-LSC whichallows adjustment of TR-LSC afterpulse timediscrimination. Background is reduced andcounting efficiency is retained for high energyradionuclides.

Time Resolution of Pulses

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3-D Energy Spectrum Plots

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Provides Superior CountingPerformance!Different sample types and counting conditions requiremore or less counting sensitivity. For low count ratesamples, background becomes increasingly important.To accurately determine the net count rate of a lowactivity sample in a reasonable time, the backgroundcount rate must be small relative to the sample countrate. PerkinElmer offers liquid scintillation detectorswith four count modes, which use increasing levels ofpulse index discrimination (TR-LSC), and providefaster and more accurate results for samples of virtually any activity.

Increase Your E2/B Up to 10 Times forBetter Sensitivity!

A. Normal Count Mode (NCM) is standard on allPerkinElmer Tri-Carb systems and reduces back-ground by more than 20–30% versus conventionalliquid scintillation analyzers (LSA). Recommendedfor samples above 500 cpm.

B. High Sensitivity Count Mode (HSCM) is for lowactivity samples and reduces background by morethan 40% versus conventional LSA. Recommendedfor samples between 50 and 500 cpm.

C. Ultra Low Level Count Mode (ULLCM) reducesbackground by more than 70% versus conventionalLSA. Recommended for samples less than 50 cpm.

D. Super Low Level Count Mode (SLLCM) is standardon all PerkinElmer 3170TR/SL models and employsa patented Bismuth Germanium Oxide (BGO)background detector guard that surrounds thesample. It reduces background by more than 90%versus conventional LSA. This Surround TR-LSCtechnology provides the highest sensitivity of anycommercial LSA. Recommended for extremely low activity samples, such as in radiocarbon datingstudies or environmental 3H. (Refer to graphs on the right.)

Decrease Counting Time Up to 100 Times forLow Level 3H Samples

The effect of TR-LSC on the time required to achieve 5% 2Sigmaaccuracy. Background sample = 12 mL Ultima Gold LLT, 8 mL “dead” water; 3H (0-18.6 keV region of interest).

Amount % 3H Background E2/Bof TR-LSC Efficiency (CPM)Discrimination

None 34.2 22.3 52

Normal 33.8 17.8 64

High Sensitivity 33.9 12.8 90

Ultra Low Level 29.4 6.2 139

Super Low Level 26.7 2.8 255

3H performance data gathered using 8 mL water and 12 mL UltimaGold LLT in glass vials. 3H energy window was 0–18.6 KeV.

Representative E2/B for TR-LSC Count Modes

(As measured in the factory in Downer’s Grove, IL using sealed standards.)

Sensitivity for ALL Low LevelApplicationsCompact Cosmic Guard LowersBackground to Unprecedented Levels

PerkinElmer offers a dedicated low level counter,which combines TR-LSC technology with BGO sampleguards, creating Surround TR-LSC, to provide theultimate in low activity sample detection. SurroundTR-LSC delivers the lowest background of any multi-purpose LSA. Not only is Surround TR-LSC sensitivityunsurpassed, but it is also simple to implement since it requires minimal programming to use in a multi-userenvironment.

Works with Low Cost, Disposable Vials

BGO sample guard technology allows you to use ordinary, disposable glass or plastic vials, while stillachieving the highest level of sensitivity. The BGOguard closely surrounds the sample vial, rejectingbackground events before they interact with the sample. With Surround TR-LSC you simply discardyour vials when assay analysis is completed.

Space-Saving Benchtop Unit

The Tri-Carb 3170TR/SL benchtop unit uses SurroundTR-LSC and is the world’s only work-anywhere, go-anywhere, true environmental LSA. Best of all, youwon’t require a special underground counting room to achieve extraordinary sensitivity.

Radon Analysis in Drinking Water

Liquid scintillation is an approved EPA method1 formeasuring radon in drinking water. The EPA hasproposed concentration limits as low as 300 pCi/L.PerkinElmer Tri-Carbs easily achieve this detection level. Detection limits of 18 pCi/L or less can beachieved in 60 minutes. Tri-Carbs equipped with thealpha/beta discrimination feature can achieve a detec-tion limit of 11 pCi/L or less in 60 minutes.1 EPA method 913.0 (SM 7500-Rn)

Surround TR-LSC reduces background, suchas cosmic radiation, by using a detectorguard. Cosmic background events interactwith the BGO guard and are rejected by TR-LSC analysis.

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222Rn Results* for Alpha/Beta LSC Method

Cocktail Optimized Region (KeV) EfficiencyA (%) Background (CPM) MDA Bq/L MDA pCi/L

Ultima Gold F 300–950 315 4.00 0.66 18

Opti-Fluor O 250–750 305 4.01 0.68 18

Insta-Fluor Plus 250–750 300 3.72 0.67 18

Mineral Oil 200–600 320 3.47 0.60 16Scintillator

10 mL cocktail + 10 mL sample; count time 60 minutes.AAlpha efficiency calculated as percentage of total radon and radon daughter emissions.*All results reproduced with the permission of Dr. Michael Cantaloub, Waste Management Federal Services, Richland, WA, USA.

Cocktail Optimized Region (KeV) EfficiencyA (%) Background (CPM) MDA Bq/L MDA pCi/L

Ultima Gold F 300–950 243 0.200 0.21 6

Opti-Fluor O 250–750 240 0.867 0.42 11

Insta-Fluor Plus 250–750 224 0.700 0.41 11

Mineral Oil 200–600 219 1.02 0.49 13Scintillator

10 mL cocktail + 10 mL sample; count time 60 minutes.AAlpha efficiency calculated from total alpha emissions only.*All results reproduced with the permission of Dr. Michael Cantaloub, Waste Management Federal Services, Richland, WA, USA.

222Rn Results* for Conventional LSC Method

Surround TR-LSC Performance of the Tri-Carb 3170TR/SL

Sample Volume CocktailA Region of Efficiency Background Count Times Target(mL water) volume (mL) Interest (KeV) % (CPM) (minutes) LLDC (Bq3 H/L)

3B 3 0.0– 4.0 19.50 0.64 470 5.0

10B 10 0.0– 4.0 19.89 0.87 60 5.0

Sample/Vial Type Counting Efficiency % Background (CPM) E2V2/B Minimum Age* Years

2 g benzene/7 mL glass 64.8 0.31 54,181 48,900

4 g benzene/7 mL glass 63.0 0.41 154,888 49,300

A Ultima Gold LLT cocktail B PerkinElmer polyethylene vial (22 mL) C A priori calculated LLD

Achieve a target LLD for 3H with either large or small volume samples with Surround TR-LSC. Data acquired and calculated at Ontario PowerGeneration, Whitby, Ontario.

Performance of the Tri-Carb 3170TR/SL for radiocarbon age dating (optimized region of interest). Data acquired at the Scottish UniversitiesResearch and Reactor Center, East Kilbride, Scotland.

*Based on a minimal detectable amount (MDA) in dpm.g-1 carbon which corresponds to At and is calculated using [2.71 + 4.65 (Nbkgnd)1/2]/Twhere Nbkgnd is the total number of background counts and T is the total count time (2,000 minutes). This expression given by Curie (1968).

A0 = 12.517 dpm.g-1 t = 1/λ ln(A0/At)

Alpha/Beta Radionuclide Counting

Many samples for environmental monitoring, nuclearpower station monitoring, drinking water analysis, andnuclear waste clean-up require analysis of total betaand total alpha radionuclides. However, in liquid scintillation counters, the pulse height spectra ofalpha-emitting radionuclides overlap the spectra ofhigher energy beta emitters, such as 137Cs, 89Sr, and90Sr/90Y. Therefore, it is necessary to employ a form ofpulse shape discrimination to differentiate alpha frombeta emissions and compensate for this interference.

PerkinElmer’s Time-Resolved Pulse Decay Analysis(TR-PDA), differentiates alpha from beta pulsesaccording to their pulse decay characteristics. Thepulse duration for alpha particles is typically longerthan for betas. TR-PDA can run simultaneously withlow level count modes, thereby achieving extremelylow misclassification of beta and alpha particles,without compromising sensitivity.

TR-PDA provides automatic or manual adjustment ofthe pulse decay discriminator (PDD). The automaticalpha/beta standard mode scans the range of possiblePDDs without operator intervention, for both alpha and beta pulses, and determines the optimum PDD for minimum spillover. In the manual alpha/beta mode, the range and number of PDD values are set by the operator.

TR-PDA Benefits

• Uses time resolution technology to analyze pulsedecay characteristics and discriminate alpha/betadecay events.

• Automatic optimization of alpha/beta separation andcounting, minimizing misclassification in a varietyof counting samples.

• Settings can be optimized and configured independ-ently for each protocol and stored for application toany other counting protocol.

Spectral overlap of 241Am (alpha) and 36Cl (Beta) radioisotopes.

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An example of alpha/beta misclassification curve from the Tri-Carbalpha/beta standards library.

LSC spectra of 222Rn - 218Po - 214Po daughters.

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Water to 3H Bkg E2/B E2V2B MDACocktail Efficiency CPM (BqL-1)Ratio

8 mL : 12 mL 24.6% 1.15 526 33680 1.22

10 mL : 10 mL 21.2% 1.11 405 40490 1.11

11 mL : 9 mL 18.1% 0.95 345 41730 1.06

Performance of Ultima Gold LLT for low level 3H using a Tri-Carb3170TR/SL. Results generated at the Scottish Universities Researchand Reactor Center, East Kilbride, Scotland.

Optimized Windows (0.4– 4.5 keV)

Water 1.0 M 2.0 M 1.0 M 2.0 M HC1 HC1 HNO3 HNO3

Sample 10.0 mL 5.0 mL 2.25 mL 3.25 mL 2.25 mLuptake capacity

Misclassifi- 1.8% 1.7% 1.0% 3.8% 4.2%cation with max sample

Performance of Ultima Gold AB with samples at 20°C using a lowlevel Tri-Carb equipped with alpha/beta discrimination (0– 2000 keVregion of interest).

Environmental SamplePreparationSample Oxidizer and Reagents:Oxidizer Simplifies Sample Preparation

PerkinElmer’s sample oxidizer makes it easy to preparemany samples containing 3H and 14C. Organic matter invegetation, animal tissue, solid waste, and even soil iseasily and rapidly oxidized into 3H2O and 14CO2, andcompletely prepared for counting. After combustion 3H and 14C are physically separated, therefore, duallabel analysis is simplified considerably. Several succes-sive combustions can be performed to enhance countingsensitivity. PerkinElmer sells a complete line of reagentsto ensure superior performance and consistency.

LSC Cocktails Ultima Gold LLT for Low Level

Ultima Gold LLT™ is suitable for the direct determina-tion of low levels of 3H in a wide range of water samples.Direct addition removes the need for distillation. UltimaGold LLT accepts up to 54% distilled water, deionizedwater, tap water, rain water, river water and has a largecapacity for sea water, with 3H counting efficiencies ofapproximately 26% and low backgrounds. When usedwith PerkinElmer’s TR-LSC technology, minimumdetectable activities of

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Glass and Plastic Vials

Glass vials, 7 mL and 20 mL, are manufactured fromlow potassium glass to ensure low backgrounds. Glassprevents solvent permeation and provides chemicalinertness with excellent visibility. Plastic vials, 4 mLto 20 mL, are manufactured from virgin polyethyleneoriginating from petrochemicals, and therefore containminimal measurable background. Plastic vials arepreferred for low level counting applications. Anti-static versions of most plastic vials are available forapplications where induced static is a potential problem.

Tri-Carb2900TR

The Complete Counting Solution!

Every PerkinElmer Tri-Carb delivers verified, reliableresults. That’s because every Tri-Carb employs patentedTR-LSC background reduction; double light seals formaximum PMT stability; low energy 133Ba external standardization for the best quench monitoring; andsafe, gravity-assisted sample downloading to prevent vial jamming and breakage.

Instruments and Electronics

• Linear MCA

• Patented, programmable TR-LSC background reduction

• Powerful, integrated computer system control and data management

• 21 CFR Part 11 compatibility

• Optimized and matched photomultipliers

• Luminescence detection

QuantaSmart™ Operating Software

• Windows® XP operating system.

• SpectraBased counting of isotopes selected fromradionuclide libraries.

• Validated instrument performance assessment (IPA™) for compliance with the EPA’s GLP recommendations and the FDA’s GMP regulations.

• Automatic calibration and normalization withsealed standards whose activity is verified againstNIST (National Institute of Standards andTechnology) material. QuantaSmart assays are easily associated or disassociated with numeric

protocol hardware flags through the associate assays dialogue.

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PerkinElmer Tri-Carbs Meet Any Counting Need, from Basic Research to Environmental Applications

SpectraWorks is the fast, efficient tool forenvironmental spectrum analysis.

Models Normal High Sensitivity Ultra Low Super Low Alpha/Count (Low Activity) Level Level BetaMode Count Mode Count Mode Count Mode Discrimination

2800TR S O NA NA NA

2900TR S O O NA O

3100TR S S O NA O

3170TR/SL S NA NA S O

S=Standard O=Option NA=Not Available

SpectraWorks™ Analysis Software

• Real-time visualization and plotting of samplespectrum.

• Helps fine-tune regions for single, dual and triplelabel assays.

• Display and analyze up to four spectra.

• Calculate detection limits.

• Confirms presence of luminescence.

• Provides evidence of quenching problems.

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Dedicated Worldwide Support NetworkPeople and applications supporting performanceexcellence.

People Putting Technology to Work for You — All Over the World

With over 10,000 instrument installations worldwide,we provide researchers with a total solution of highquality instrumentation and application expertise. Wehave more than 300 highly trained service engineers inmore than 60 countries. This makes PerkinElmer thelargest, most well trained liquid scintillation analyzerinstrument service organization in the world.

Tri-Carb Bibliography and ApplicationNotes

PerkinElmer’s instruments are the most cited liquidscintillation analyzers worldwide. Our current appli-cation bibliography, available on request, cites over1,000 articles in open scientific literature, describingresults of research conducted using liquid scintillationanalyzers. We continually publish application papersfrom researchers and our own application specialistshelp inform researchers about the latest in liquidscintillation technology. PerkinElmer products are designed and manufactured under an ISO 9001 certified system. They are designed, built, and tested in conformance with appropriate CSA, FCC, and IEC standards.

PerkinElmer is recognized worldwide for advanced instrumentation systems and outstandingcustomer support. We continue to be your partner in life science research providing instrumentsfor scintillation, gamma, and microplate counting; quantitative imaging; and liquid handling. We are committed to providing the best instrument application support, field service, and telephonesupport. We are proud of our tradition of working with laboratories to accelerate the pace of lifescience research.

LSA Reliability and Performance You Can Count On

Make the only choice, the Tri-Carb LSA, only fromPerkinElmer. You’ll get superior low level sensitivityand performance for every research or environmentalapplication challenging your lab. For more informationor for help placing an order, call 1-800-762-4000 orvisit www.perkinelmer.com/LSAS.

For a complete listing of our global offices, visit www.perkinelmer.com/lasoffices

©2005 PerkinElmer, Inc. All rights reserved. The PerkinElmer logo and design are registered trademarks of PerkinElmer, Inc. IPA, QuantaSmart, SpectraWorks and Ultima Goldare trademarks and Tri-Carb and TR-LSC are registered trademarks of PerkinElmer, Inc. or its subsidiaries, in the United States and other countries. Windows is a registeredtrademark of Microsoft Corporation. All other trademarks not owned by PerkinElmer, Inc. or its subsidiaries that are depicted herein are the property of their respective owners.PerkinElmer reserves the right to change this document at any time without notice and disclaims liability for editorial, pictorial or typographical errors.

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PerkinElmer Life and Analytical Sciences710 Bridgeport AvenueShelton, CT 06484-4794 USAPhone: (800) 762-4000 or (+1) 203-925-4602www.perkinelmer.com