ER R.aord 1.0.• lj8017

LOS AI..AMOS.NATIONAL ~&4TORY EM'IRONMENTM ltBST0&4TION

/Ucpr/i~l"' F~ ER R«ord61tulex Form

ERID NO. 58017 Dtde Received: 6/11/98 Procenor: YCA Page Count: 29

• · .. :·. ~ell: (YIN) N Ret:OI'tl Category: P Record Pac/cage No: 0

Corredd No. 0 Correcte4 By Number: 0

y

Olll ER lp Number: 0 New ~R 1D Number: 0

IIIII II IIIII llll/1/llll/111111 3011

.· , · •. . .-~,,~ ... ~ Nat~nal Laboratory No: LANL-ER-SOP-14.01 Rev: 0 ·.·· env_ti,onrne(''-1 Res,toratlon Program

•. · ·.·~~"'. Operatl~- Procedure

<BE-RTHOLD LOW ALPI-IA AND BETA ACTIVITY COUNTER · · ~ .CALIB.,ATION, QUALITY CONTROL, DETECTION LIMIT, AND USE

~Ill~ .Jbuw• ~Li.. "3rJ.rp . rf:/za(9J (Prirt Name) nature) ( )

·~.·· Revlewby ~wg_ ~\.u~ ~24 · . :· · ( rt Name) (S n ure)

• • •, I :~ :r~.:-': : • ' .. L;,:!·

. . ~ ~ ·.,-.. •':: ~.

CU~PL 'Appreval I .~... :'':, ~ ~ • • •

bei!J,-~~ ifl"'ctJK.f (Print NSme)

~ () 1lo'{f_e. iftoc-\-2

(Signature)

" &t·L. AAMoJ.t (Prirt Name) · ~~ (Sign ture)

~~..1 (D e)

Effective Date: ~- \ 0 - 9 'S Received by ER·RPF

JUN 1 \ 1998 era

LANL·ER·SOP·14.01, RO Page 1 of 13

BERTHOLD LOW AI.PHA AND BETA ACnVITY COUNTER CALIBRATION, QUALITY c:ONTROL, DETECTION LIMIT, AND USE

Contents

1.0 PURPOSE .......••.•••...•..................•.................................•........•...............•..••••••••....• 2

2.0 SCOPE .................................................................................................................... 2 2~ 1 Applica.billty .......................... ························ .... ·······································-·2 2.? T~ning •....................................................................................•............•••.. 2

3.0 OEFINmOOS .......................................................................................................... .3

4.0 QACKGROUNO AND PRECAUTIONS .............................................................. 3

5.0 EQUIPMENT •••..........•....................•.............................•............................•....••...•.. 4 (·

··. :!:.. , ..

. 6.0 P,ROCEDURE •••••••••.•••••.••••••...••.••••....•....•.••..•.•..•.......••.•••••..••••••.••.•.....••••••••••••••••••• 4 6.1; PIEltfiS..U Counting ...................................................................................... 4 6.2--c~n-of_ Op!eration Point ................................................................ s 6.~:- .--Bael{g'to_u~ Cotlnting .............................................................................. & 6~4 O~~@if'!~pn of'Lower Level of Detection (Lo) .................................. 6 6.5::· Calibration: •. ~.:.· ... ~ ....................................................................................... -.7

... ,. ~.-·: ... ·~t~l~~~:-'~:M·a,:t.~~························································································a _. ··.·:_6J~~--~:·-~tatif1g ·Procecfures ............................................................... a 6.6: _ ~WP'~fer~p,~t•~ion ................................................................................. 9 .6.7;·::.-~,~P,{•!t~.urt•~g .......... , ................... ~ ....................................................... 9

. --~~13-- _P~If.9.~!lce-·CH.eck .................................................................................. 1 o · · ... 6.9--: ;QLJ!=l1J.t)f..9<:)_ntrol (QC) Samples ................................................................ 11

. ·. 0 7.() ~;~~ .~RA"(URE ·································································---·11 -·s~o REQ.ORDS·-............................................................................................................ 12

-.9.0 ATIACHMENTS .................................................................................................... 12 ·.,:.

r

LANL-ER-SOP-14.01, RO Page 2 of 13

BERTHOLD LOW Al.PHA AND BETA ACTIVITY COUNTER CALIBRATION, QUALITY CONTROL, DETECTION LIMIT, AND USE

1.0 PURPOSE

The following procedures outline the methods involved in the use of the Environmental Protection Group's (EM-S's) Berthold Low Activity Alpha and Beta Counter for screening alpha and beta activity in soil samples (see references in Section 7). Specific procedures are given for: 1) Plateau Counting, 2) Background Counting, 3) Calibration, 4) Sample Preparation, 5) Sample Counting, and 6) Performance Check.

2.0 SCOPE

The use of this instrumentation establishes adequate controls to ensure that correct and acceptable measurements will be collected in support of Environmental Management (EM) operations accomplished for the Department of Energy.

2.1 Applicability

This instrument is used in soil radiological surveys conducted by the Waste Site Studies (WSS) section of EM-8 at the Los Alamos National laboratory (the Laboratory). The Waste Site Studies section is supported, in part, by the environmental surveillance program for the Laboratory Material Disposal Areas (MOAs), the Environmental Restoration (ER) Program, investigations of Solid Waste Management Units (SWMUs), and Waste Management activities at the Laboratory.

Because the Laboratory routinely handles and disposes of waste contaminated with alpha· and beta-emitting radionuclides, a detector that can measure levels of contamination by these radionuclides is required. In addition, before soil samples are allowed to be submitted to EM-9 at TA-59, OH-1, the samples must be screened for gross alpha and beta activity. The Berthold gas proportional counter can simultaneously measure alpha and beta activity levels in up to 10 soil samples.

2.2 Training

User training shall be the responsibility of the principal instrument operator or EM-8 personnel trained by the principal instrument operator. During preparation of these soil samples, small quantities of dust containing low levels of alpha and beta emitters may be generated. All personnel using these procedures must have received Radiation I or II, as well as HAZWOPER training and will be apprised of proper housekeeping and hygiene protocols required to minimize hazards associated with using the Berthold.

'

2 ....

""' .... !:? fJ 1 ? .. :j

.·,.

' ~ •• ...

, I

'-

LANL-ER-SOP-14.01, RO Page 3 of 13

3.0 DEFINITIONS

A. Alpha Particle: A charged subatomic particle containing two protons and two neutrons that is sometimes Etmitted from the atomic nucleus during radioactive decay. A typical energy level for most alpha emitters is about5 MeV.

B. Beta Particle: A type of subatomic particle that can be negatively or positively charged (positron), and is sometimes emitted from the atomic nucleus during radioactive decay. The rest mass of the beta particle Is equal to that of a normal electron.

c. Proportional Counting: A method of discriminating the detection of an alpha versus a beta particle based on the amount of energy deposited In the detector.

D. Specific Activity: Total activity of a given radionuclide per gram of a compound, element. or radioactive nuclide.

E. Background Counting: A soil background check is recorded for the detector. This serves to establish a priori the number of counts (or count rate) required to Indicate possible contamination of a sample. A background count rate (R) Is measured, and a confidence Interval is calculated to establish the background activity distribution.

F. Lower Level of Detection: This is the minimum radioactivity concentration level encountered necessary to be considered statistically separate from the normal, background distribution of radioactivity in the environment.

G. Control Counting: Performance checks are undertaken to certify that the instrument is operating properly. Planchets with known activities are introduced Into the instrument and the measured activities must be within specified limits defined for the Instrument. {In addition, control samples of known activities are periodica11y introduced into the instrument during normal runs. The measured activities of these known standards must also fall within specified limits.)

4.0 BACKGROUND AND PRECAUTIONS

Gas flow proportional counting is a convenient, sensitive method of simultaneously counting alpha and low-energy beta particles.

The Berthold instrument is used to screen soil samples for low levels of alpha and beta emitters. One gram of a soil sample Is placed in a planchet and emissions are counted in the detector. One can convert the counts measured into sample alpha and ·beta activity based on the count yield for the alpha and beta channels. The calibration of the instrument is performed using soil standards prepared by the Health and Environmental Chemistry Group {EM-9).

Some of the advantages of gas proportional counting over Geiger-Muller counting include:

!

.· •.

'·'·'

r

r

LANL-ER-SOP-14.01, RO Page 4 of 13

• a thin window which minimizes inherent absorption,

• the chamber allows 2 Pi geometry, which improves count yield,

• alpha and beta emitters in the same sample can be counted simultaneously using different discriminator settings.

The major disadvantage of the gas proportional counting may be imprecision of results caused by the non-homogeneity of the prepared samples, and the inability to distinguish what isotope is contributing to the gross radioactivity of the sample.

PRECAUTIONS

The Instrument should not be turned off. When terminating the LB770 PC program, the high voltage should be set to zero.

Never lnffiate counting unless the gas flow (P-10, argon-methane) has been flowing through the system for 30 minutes. High voltages to the anode wire may degrade the wire unless the counting gas Is in equilibrium with the instrument.

Never allow the counting carrier gas to exceed the capacity of the gas-flow meter. This can damage the mylar window covering the detector. Care should be taken when Initiating the gas flow to the detector; turn the needle and pressure valves in small increments until the ball in the flow rate meter begins to move, then adjust to the correct flow.

Always prepare an soil samples under the hood provided in the count trailer. This precaution is taken to minimize dust generation in the t~iler.

5.0 EQUIPMENT

The equipment required for the operation of the Berthold Low Activity Counter system includes:

6.0

1) Berthold instrument system 2) Pfanchets 3) Various performance check sources and standards 4) P-10 gas (Argon/Methane)

PROCEDURE

6.1 Plateau Counting

Procedure for Determining Proper Operating Potential of the BERTHOLD Low Activity Counter.

'· .,; ·.:. ~-,: ··:---/'·' :•,.;::.·,~··.;. ,··· ..

; ~. r. · . ..r ...... !

~

l • :5

'I

LANL-ER-SOP-14.01, RO Page 5 of 13

Tum on the argon/methane gas flow (P-1 0 counting gas) so that the float ball is between 1 0 and 1 5 units on the flow rate meter, and allow 30 minutes for the gas flow through the instrument to reach equilibrium.

Initiate the software by typing Berthold and <ENT>.

Use the arrow keys to select Measure in the Main Menu. Hit <ENT> to get into the Measure window.

Use the arrow keys to select Plateau in the Measure window, and again hit <ENT>.

At this point, you will be prompted for a file name for the count data to be collected. Enter the file name, for example: PL-MMPDA where MM stands for the current month, and DO stands for the current day, and A stands for the first reading of the day. Hit <ENT> after typing in the file name.

You will be prompted for the type of emission you are counting:, Alpha or Beta Enter A(lpha) or B(eta) and hit <ENT>.

You will be asked to place the standard sources (alpha or beta emitters) in the planchet holders in the detector. After this has been done, hit <ENT> to begin counting for a standard time period.

Repeat this procedure so that plateaus are measured, separately, for both alpha and beta activities.

6.2 Calculation of Operation Point

Procedure for determining the optimum high voltage setting . • Use the arrow keys to select Data Handling at the Main Menu. Hit <ENT> to get into the Data Handling window.

Use the arrow keys to select Operation Point Calc. in the Data Handling window. Again hit <ENT>.

The parameter table, Calculate Operation Point, will appear. The names of the files of the last alpha and beta plateau measurements will be listed along with the plateau slopes and spillover. Hit Ctri-<ENT> to accept the entries.

After confirmation, a window listing the suggested HV-Operation Point will be displayed. Make a note of this value.

Plateau measurements will have to be done periodically or if performance checks indicate measurements are "Out of Control.• It is good practice to generate new plateaus whenever the P-1 0 gas tank or mylar window is changed.

.;·o,,' .·•·.·

6 •

..· •... I'

I· 6.3 Background Cou11tlng

LANL-ER-SOP-14.01, RO Page 6 of 13

Procedure for determining proper background of soil samples for the Berthold low activity counter.

Tuff-derived soil background samples for this instrument come from sand traps used in LANL water supply wells.

Tum on the Argon/Methane gas flow (P-1 0 counting gas) so that the float is at 1 0 units on the flow meter. Allow 30 minutes for the flow through the chamber to reach equilibrium.

Initiate the software by typing Bertho!g and <ENT>.

Use the arrow keys to select Parameters at the Main Menu. Hit <ENT> to get into the Parameters window.

Select the Background option of the Parameters window. When the table of parameters appears, input the necessary data, and hit CTRL-<ENT> to save and store the parameters in the background file.

Then select the ~ option of the Parameters window. Select New parameter and use the Defaults. Enter a file name, and the suggested HV-Operation Point that was calculated previously. Hit CTRL-<ENT> to save and store the parameters in the user file.

Use the arrow keys to select Measure at the Main Menu. Hit <ENT> to get into the Measure window.

Select the Backgroung option in the Measure window. You will be prompted to select a user parameter file. Select the user file containing the suggested HV-Operation Point and hit <ENT>. The background measurements will automatically be saved into this file.

Insert the planchets with background soil into the planchet holders and hit . <ENT> to begin counting samples for an allotted time period. The activity of the ~ background soil samples will be automatically calculated and printed out in a hard copy. The operator can select whether to measure in counts or picocuries. ':

6.4 Determination of lower level of Detection (l0 )

The Lower level of Detection represents the lowest amount of radioactivity in a sample needed to be considered greater than background. (For this instrument one must calculate L0s for both alpha and beta detection.)

.. -:· .. -·· . ·I·.•' ' ·I"~

•

..

; . .. "I,

.... , ...

7

; ..

;·r

r

The L0 can be calculated as follows:

LANL·ER-SOP-14.01, AO Page 7 of 13

L0 = 2. 71 + 4.65 (u8) 112 (see appe~dix A)

where, u8 is the mean measured activity for the background soil.

6.5 Calibration

Calibration for alpha and beta counting of soils is accomplished by counting samples of clean soil (the same soil that was used for the background measurement) that have been spiked with known amounts of an alpha· or beta­emitting radionuclide. Prior to spiking the soils, the alpha and beta background count rates should be determined for the background soil to be used (as discussed above). For optimum results, the spiked sample (standard) should consist of the same material and should be placed in the planchet In the same configuration as the soil samples that are to be counted on a routine basis. The radionuclides used for preparing standards should have similar decay energies to those that one expects to encounter in the unknown soil samples. By comparing the true activity of the standard soil samples to the activity that is actually measured, the instrument will calculate the efficiency for detecting alpha and beta emissions in each channel. These efficiencies will take into account the geometry of the set-up, the response probability of the detector, the type of calibration source, back scattering and self-absorption.

The equation for determining instrument efficiency is:

Eff. =Cl)m/60 A

where, cpm = count rate corrected for background and half-life

and A = activity in Bq of the source [Bq is Becquerels (counts/sec)) A number of alpha emissions will also be registered in the beta channel during simultaneous alpha/beta measurements. The spillover factor corrects for this "spillove,... or "crosstalk" into the beta channel. This factor will be determined in the alpha calibration measurement. (Spillover from the beta to alpha channels is considered negligible.)

The equation for calculating the spillover factor during the alpha calibration measurement is:spillover factor= beta count rate/alpha count rate

Because the efficiency factor is calculated within the software of the instrument, the external algorithm simply converts the activity of the soil sample from counts per minute (cpm) into pCi/g (since one gram of dry soil will be counted).

This conversion uses the following algorithm:

• s. a 0 ;

,.

.,.,

... :~:.

- .

.. ·-

LANL·EA-SOP-14.01, AO Page 8 of 13

(SA/2.2212) • 1.012. pCi/g

where, SA • sample activity in cpm

2.2212 .. conversion unit to Ci

1.012- conversion unit to pCi

6.5.1 Materials

1) Berthold system

2) Spiked soil sample set in planchets

6.5.2 Operating Procedures

Use the arrow keys to select Parameters at the Main Menu. Hit <ENT> to get into the parameters window.

• q

II

"" . Select the Calibratjon option of the parameters window. Select tUtw '-l: earameters and hit <ENT>.

When the table of parameters appears, input a file name, the type of emission you are counting ((A)Ipha or (B)eta), the measurement time, and sample identification numbers. The count time depends on the application and the desired detection limits and is left to the discretion of the operator. Hit PgDn to get to the second parameter page and enter the half-lives, manufacture date and initial activities of your spiked samples. Hit CTRL-<ENT> to save and store the parameters in the parameter file.

Place the spiked samples in the planchet holders in the order that they appear in the table of calibration parameters. Generally, a spiked set of samples spans an activity range of, for example, 15 - 500pCi.

Use the arrow keys to select Measure in the Main Menu. Hit <ENT> to get into the Measure window .

Use the arrow keys to select Calibration in the Measure window, and hit <ENT>.

You will then be prompted to select a user parameter file. Select the file in which you stored the background measurements, hit <ENT>. (The calibration results will also be stored in this file.)

Next, you will be asked to select a calibration parameter file. Select the file that was just created and hit <ENT>.

, I

)

LANL-ER-SOP-14.01, RO Page 9 of 13

To begin the calibration hit <ENT>.

Repeat this process so that calibration measurements have been performed tor both alpha and beta sources.

6.6 Sample Preparation

The samples should be prepared according to the method developed by the user, but preparation of the planchets should be the same as preparation of both background and standard soil sample sets. The planchets will be properly labeled to allow easy identification and tracking through the count lab. A sample label shall consist of a alpha-numeric identification number (10#). For ER samples, a unique Facility for Information, Management, Analysis, and Display (FIMAD) number is assigned to each sample. For instance, in samples from TA-1, the unique FIMAD number may be 01-1513T.

Open the container holding the soil to be counted. (If the soil is moist, place a few grams of the sample in a petri dish and dry under a heat lamp before proceeding.)

Record the sample number on the bottom of the planchet using a sharpie pen.

Spray the inside of the planchet with a thin film of adhesive.

Place the planchet on the balance and hit the tare button of the balance (this resets balance to zero).

Add the sample to the planchet until the balance reads 1.00 ± 0.01 grams. If possible, try to remove large particles from the planchet, maintaining maximum particle size homogeneity of the sample.

Use a wooden tongue depressor to more evenly spread the sample over the surface of the planchet.

6.7 Sample Counting . l ~ The samples are placed in the detector in pre-designated locations, and i counting is initiated. At the end of the count time, the data is displayed, and may be output to a printer and to a pre-specified data file. i

Tum on the Argon/Methane gas flow (P-1 0 counting gas) so that the float ball \s between 10 and 15 units on the flow meter, and allow 30 minutes for the gas 4 flow through the chamber to reach equilibrium. J Initiate the software by typing Berthold and hit <ENT>.

Use the arrow keys to select Parameters at the Main Menu. and hit <ENT> to get into the Parameters window.

• ~ .. / ;;;, ··' () 1. .... I

1 i. J

r

LANL-ER-SOP-14.01, AO Page 10 of 13

Select the~ option of th•~ Parameters window and hit <ENT>. Select the user parameter file that con·tains all of your background and calibration data. Hit PgDn until you reach page 5. Use the arrow keys to move around on the page and enter in 27.0 as the normalization factors for channels 6-10. Hit PgDn again to reach page 4, enter 27.0 as the normalization factors for channels 1-5. This will allow you to measure activities in the units of pCi/g. Hit CTRL-<ENT> to save and store this information in the user parameter file.

Use the arrow keys to select Measure at the Main Menu. and hit <ENT> to get into the Measure window.

Select the Sample option from the Measure window. Select the user parameter file that contains your background and calibration results, hit <ENT>. In the table provided by the menu, input a file name and sample identification number(s) and hit CTRL-<ENT> to save and store the information to the file.

Place the planchets in the holders that correspond to the sample identifiers given in the above step. Slide the sample drawer into the detector housing, and hit <ENT> to begin counting.

To view the results on the screen in pCi/g, use the arrows to select the Acti<>cpm option during the measurement and hit <ENT> until the activities are displayed in pCi/g. Note the calculations handled by the associated software package of the LB770 correct for the background, spillover and efficiency factors that were determined in the calibration. The activities measured are those above the mean (clean soil) background activity.

6.8 Performance Check

The user should make a performance check each day to ensure the detector system is operating properly.

At the beginning of the day, turn on the argon/methane gas flow (P-10 counting gas) so that the float ball is between 1 0 and 15 units on the flow meter, and allow 30 minutes for the gas flow through the chamber to reach equilibrium.

Initiate the software by typing Berthold and <ENT>.

Ten bare planchets, each containing 1 0 pCi of either alpha or beta activity, should be prepared for the performance check.

Select Calibration in the Parameters window and set up a New Parameters file using the same procedure that was used for the calibration measurement (see 6.5.2.3). Hit CTRL-<ENT> to save the information.

Select Measure from the Main Menu. Hit <ENT> to get into the Measure window.

2 0 r-",]

• t.: ...• 8 "· '.)

l 7

.1. l

I 'J T 'L .,

I

r

<·

LANL -ER-SOP-14.01, RO Page 11 of 13

Select the Performance option in Measure window, hit <ENT>.

z 0 6 s. ij 0 1 7 You will be prompted to select a user parameter file, choose the one which • contains the correct calibration factors, background and HV-Operation Point. 1 Hit <ENT>. Then you will be asked to select a calibration file, choose the file Z. that contains the activities, half-lives, and manufacture dates for your performance check samples and hit <ENT>.

Place the ten spiked planchets Into the holders, and initiate counting by hitting <ENT>.

If the counts do not exceed the maximum deviation defined by the user the system will signal "Performance Check OK!" Print out copies of all Performance Checks and compare each printout with previous printouts. If any systematic drifts are apparent or the instrument does not signal OK, notify the principal instrument operator before continuing with any sample measurements. 6.9 Quality Control (QC) Samples

Quality Control samples of known activities will periodically be counted along with unknown samples as a Quality Assurance (QA) check. The QC samples which are made from a variety of activity levels of 241Am and 137Cs on clean (background) soil, and should comprise approximately 10% of the total number of samples that will be analyzed. These QC standards should be interspersed and run with the samples. Alternatively, pre-prepared radioactive standards embedded in planchet sized holders may be utilized as control samples. Load the samples and OC's into the planchet holders and count the samples as described in section 6. 7 Sample Counting.

7.0 REFERENCE LITERATURE

This bibliography lists documents that relate to this procedure and that provide additional pertinent information to interested users.

Currie, Uoyd A., "Limits for Qualitative Detection and Quantitative Determination; Analytical Chemjstt:y, 40{3), 586, 1968.

Department of Energy Order 5700.68, "Quality Assurance," DOE, 1986.

EG&G Ortec, "Berthold, LB770 PC 1 o Channel Alpha-Beta Counter, 1st Edition• EG&G Ortec, 100 Midland Rd., Oak Ridge Tennessee, 37830. 1991.

EG&G Ortec, "Maestro II A64-BI Software Operators Manual Version 1.0" EG&G Ortec, 100 Midland Rd., Oak Ridge Tennessee, 37830. 1991.

'"' . '

..

LANL-ER-SOP-14.01, RO Page 12 of 13

Fraley, Leslie, Jr., "Radiation Detection and Measurement· A laboratory Manual.• Colorado State University Publica~ions, Fort Collins, CO, Aug. 1991. Grant, Eugene and Leavenwo,rth, Richard, "Statistical Quality Control. • McGraw Hill, -~19n f Koch~r. David C •• •Radioactive Decay Data Tables,• Report DOEITIC.11028, Technical Information Center, U.S. Department of Energy, Washington, D.C. 1981.

: U.S. Depa.rtinent of Health· Education and Welfare, "Radiological Health Handbook. • Bureau ()f Radloleglcal Health, Rockville, MD, 1970.

; s~o R~CO~DS

· : Recor.c:f$}elatJng to :.the calibration, maintenance and use of the counting system are . · :r.nai~t~~:bycm,.·pr1pclpal~lnstrument.operator o~ de~lgnee. Records of samples · ~U!J,~~J.i.sir1g:Jh,·e·:equn,ting;:s}'$t~IJ1.ar$: m~~ne9:~y;the,;v~ous usgr,s of .thf .

•

. · · instf1.!":1e!Jr.i~.J:,M;~; Pri.ort~ s~brplttin_g th,~ AAIDJ)I,~~ tQ:EM.;g fQrr~oisotQJ)k: analysis, · ·,.11 ~atd :CC?PY·,of'1~~<~ta g~t~.efiKI.by the ln~rumem:fQr that' partiCUlar set of samples is ~ . p~~~~~ -~~~}~~-sam pi~ Scr~enhig purpC)ses~-- It is th~ responsibility of the OUPL to ~ . ·. ':· ensure:that rel~anr record$ are transmitted to RPF, MS M707. . . . . ... . .

. ·' 9.0 : ATr ACHMENTS

· '_ Attachment A ~ Appendix A

)

r

r-(17;;;~-·~~,:~':.':~-~~~~s~~".?x~~~-:J · ~: --~::~~:r.~ rr;~~:¥-~~?~~~~~}~~~~;~:?l~~+r~~9T-i·f~;~ .. ~r(1~~r~·~~~;;~rf~~~~:~~;r ..

.. , ;

Appendix A

LANL~EA;;SOP-14:(J1,-.. Attachment A Page 13 of 13

. .· :' -~:. ·.~:;[-r::\;. ,:· .-~~ ~ / . ~: ·· .... :'· ~·-· . ~··

::~:};-:(:F9lt~•:·.l38.!'!h*,~~:Q'Q curr~ntly being us~ by the Waste Site Studies Section of ·. ··.;[:~:~.~§;!t:["~SQ:th~'~lculatlon of the Lower Levels .of Detection were performed as

::::i}},~!~N~~;~f-:·.:,').:::~~ :. . . · .:?::~ , ·~~(-, : :(f~r the .c:fet~ion of beta activity)

. : .. · .. "r\-' : .. ,_, u_:_.e·;·_. --~-· :;~_!,·;_. __ /_. __ ,8_. ~-~-· '"·· . ·_.

t"',~;,· L6 ... #f~.+~4.~s (1~.a)112 .. ·~.:.~~i~~t_·.91jC'' (1 pCi • 2.22 cpm)

· (fQr the:p~~iorfof ~pha activity)

f[~:~_f;!~\~s _;_;;.:Lst~c~g:r~t.~,.na: n~'iSUren1ents w~r~u>er:tormed on· samples containing 1 gram of soil,

-reaJJf'pCi/g.

. ·. -~ · .... · .

. ., ... _

'I

Loe Alamoe National Laboratory No: LANL-ER-SOP-14.01 Rev: 0 Environmental Reatoratlon Prog~ram Standard Operating Procedure

BERTHOLD LOW ALPHA AND BETA ACnVITY COUNTER CALIBRAnON, QUALITY CONTROL, DETECTION LIMIT, AND USE

Prepared by

(Dale)

Technical a ef!;rf~ ffrctJK.f by~ ,oJ,~llJ? Review by

(PriBN:nle) (Signature

"\

PM Approval &l L. AAMoJ.t iZt~ ti(.b3 (Print Name) (Signature) ( t

QPPL Approval

Effective Date: ~- \ 0 - 9 S

; ·'

}: .. ~

LANL·ER·SOP-14.01, RO Page1 of 13

BERTHOLD LOW ALPHA AND BETA ACnVITY COUNTER CALIBRATION, QUALil'Y CONTROL, DETECTION LIMIT, AND USE

Contents

1.0 PURPOSE ............................................................................................................... .2 2.0 SCOPE. •................................................................................................................. .2 2.1

2.2 Ap.ptica.blllty ••••...•..••..•.•..••......•.....••••••....•..••.••.••....•...•••••..•••.••••••..•••.•••••••.••• 2 Training •••.•.....•.•......................•.•................•...... ~ ...•••.•..•...•.•.•••...•.••••.•••••••.•• .2

3.0 DEFINITIOOS •.•••••••••.••..•.•....•..........•.•...••.........................•••....•.....••..•••..••.•..•••......• 3 4.0 BACKGROUND AND PRECAUTIONS .............................................................. 3 5.0 EQUIPMENT ••.•.••.•.•••.......••..•.•......••........••.....•....••...•.•......•••.•......•......••...•..•.•..•.•.•. 4 6.0 PRCX::E;DURE.-........................................................................................................ 4 6.1

6.2 Plat•u Counting ..•.••......•.................................•......................•...•...•....••.. 4 ~n of ~ration Point .............................•........•...............•......... 5 6.3 . S~ground COunting .............................................................................. & 6.4 Determination of Lower Level of Detection (Lo) .................................. 6 6.5 C811bratfon •••••• :. •••.•••.•••••••.••..•.......••••.•....•...........•....•.••.•..••..••.•••••••••••.••••••.• 7 6.5~:1 ·Materials ••.••••••..•...•.....•...••••....•••••...•........••.•.•.••.•...••••.....••••.••..•..• & 6.5.2 .. Operating Procedures. .•....••......•.•.•.•..•....•...•........•..••....•••••••...•• 8 6~6 SampJe· .. f:.rfP&t.ation .................................................................................. & 6. 7 Sarnptj. ·Counting ...................................................................................... 9 6.8· P~.!'fc)rma_~ce Check .. ~ ............................................................................... 1 0 6.9 QUality Control· (QC) Samples ................................................................ 11

1.0 REFERENCE LITERATURE ................................................................................ 11

8.0 RECORDS ··-··········································································································12 9.0 .A TT' ACHMENTS .•....•.....•.....•................................................•.••..•...•....•.....•..•.......• 1 2

)

. •.

:· - • ';;· v

LANL·ER·SOP-14.01,RO r' Page 2 of 13 •

BERTHOLD LOW ALPHA AND BETA ACTIVITY COUNTER CALIBRATION, QUALITY CONTROL, DETECTION LIMIT, AND USE

~ 0 1 -~

• 1~ PURPOSE '

The following procedures outline the methods involved in the use of the Environmental l . Protection Group's (EM·S's) Berthold Low Activity Alpha and Beta Counter for screening alpha and beta activity in soil samples (see references in Section 7). Specific procedures are given for: 1) Plateau Counting, 2) Background Counting, 3) Calibration, 4) Sample Preparation, 5) Sample Counting, and 6) Performance Check. 2.0 SCOPE

The use of this instrumentation establishes adequate controls to ensure that correct and acceptable measurements will be collected In support of Environmental Management (EM) operations accomplished for the Department of Energy. 2.1 Applicability

,.

-~ 1 T: ... This Instrument is used in soil radiological surveys conducted by the Waste Site· · .1. Studies (WSS) section of EM·8 at the Los Alamos National Laboratory (the 'R Laboratory). The Waste Site Studies section is supported, in part, by the environmental surveillance program for the Laboratory Material Disposal Areas · ·\ (MOAs), the Environmental Restoration (ER) Program, investigations of Solid · Waste Management Units (SWMUs), and Waste Management activities at the Laboratory.

Because the Laboratory routinely handles and disposes of waste contaminated with alpha- and beta-emitting radionuclides, a detector that can measure levels of contamination by these radionucfides Is required. In addition, before soU samples are allowed to be submitted to EM-9 at TA-59, OH-1, the samples must be screened for gross alpha and beta activity. The Berthold gas proportional counter can simultaneously measure alpha and beta activity levels in up to 10 soil samples.

2.2 Training

User training shaJI be the responsibility of the principal instrument operator or EM-8 personnel trained by the principal instrument operator. During preparation of these soil samples, small quantities of dust containing low levels of alpha and beta emitters may be generated. All personnel using these procedures must have received Radiation I or II, as well as HAZWOPER training and will be apprised of proper hou&ekeeping and hygiene protocols required to minimize hazards associated with using the Berthold.

:i.

r

LANL-ER-SOP-14.01, RO ~ Page 3 of 13 ~

r;.: ·" 3.0

A.

DEFINITIONS

Alpha Particle: A charged subatomic particle containing two protons and two neutrons that is sometimes emitted from the atomic nucleus during radioactive decay. A typical energy level for most alpha emitters is about 5 MeV.

B. Beta Particle: A type of subatomic particle that can be negatively or positively charged (positron), and is sometimes emitted from the atomic nucleus during radioactive decay. The rest mass of the beta particle is equal to that of a normal electron.

C. Proportional Counting: A method of discriminating the detection of an alpha versus a beta particle based on the amount of energy deposited in the detector.

0. Specific Activity: Total activity of a given radionuclide per gram of a compound, element, or radioactive nuclide.

E.

8 0 1 '/'

' !

Background Counting: A soil background check is recorded for the detector. This serves to establish a priori the number of counts (or count rate) required to indicate possible contamination of a sample. A background count rate (R) is measured, and a confidence interval is calculated to establish the background activity distribution.

,.

F. lower level of Detection: This is the minimum radioactivity concentration level encountered necessary to be considered statistically separate from the normal, background distribution of radioactivity in the environment.

G. Control Counting: Performance checks are undertaken to certify that the instrument is operating proper1y. Planchets with known activities are introduced into the instrument and the measured activities must be within specified limits defined for the instrument. (In addition, control samples of known activities are periodicafly introduced into the instrument during normal runs. The measured activities of these known standards must also f~ll within specified limits.)

4.0 BACKGROUND AND PRECAUTIONS

Gas flow proportional counting is a convenient. sensitive method of simultaneously counting alpha and low-energy beta particles.

The Berthold instrument is used to screen soil samples for low levels of alpha and beta emitters. One gram of a soil sample is placed in a planchet and emissions are counted in the detector. One can convert the counts measured into sample alpha and beta activity based on the count yield for the alpha and beta channels. The calibration of the instrument is performed using soil standards prepared by the Health and Environmental Chemistry Group (EM-9).

Some of the advantages of gas proportional counting over Geiger-Muller counting include:

, I

' '-

.j J ...

LANL·ER·SOP·14.01, RO 2 Page 4 of 13 ,

• a thin window which minimizes inherent absorption,

• the chamber allows 2 Pi geometry, which improves count yield,

~ 0 1 7 • fJ • alpha and beta emitters in the same sample can be counted simultaneously 0 using different discriminator settings.

The major disadvantage of the gas proportional counting may be imprecision of results caused by the non-homogeneity of the prepared samples, and the inability to distinguish what isotope is contributing to the gross radioactivity of the sample. PRECAUTIONS

.. ! ~

..

.. ~ .,.,

The instrument should not be turned off. When terminating the LB770 PC program, the '·', high voltage should be set to zero. i ,. Never initiate counting unless the gas flow (P-10, argon-methane) has been flowing through the system for 30 minutes. High voltages to the anode wire may degrade the wire unless the counting gas is in equiUbrium with the instrument. Never allow the counting carrisr gas to exceed the capacity of the gas-flow meter. This can damage the myJar window covering the detector. Care should be taken when initiating the gas flow to the detector; turn the needle and pressure valves in small increments until the ball in the flow rate meter begins to move. then adjust to the correct flow.

Always prepare all soil samples under the hood provided in the count trailer. This precaution is taken to minimize dust generation in the trailer.

5.0 EQUIPMENT

The equipment required for the operation of the Berthold Low Activity Counter system includes:

1) 2) 3) 4)

Berthold instrument system Planchets Various performance check sources and standards P-10 gas (Argon/Methane)

6.0 PROCEDURE

6.1 Plateau Counting

Procedure for Determining Proper Operating Potential of the BERTHOLD low Activity Counter .

.,.., ~ .. •: ..

r

!',•' (

•'

.,.•;ol

LANL-ER-SOP-14.01, R0 ~·· . Page Sof 13 •

Tum on the argon/methane gas flow (P-1 0 counting gas) so that the float ball is between 1 o and 15 units em the flow rate meter, and allow 30 minutes for the gas flow through the instrument to reach equilibrium.

~

Initiate the software by typing Berthold and <ENT>.

Use the arrow keys to select Measure in the Main Menu. Hit <ENT> to get into the Measure window.

Use the arrow keys to select Plateau in the Measyre window, and again hit <ENT>.

At this point, you will be prompted for a file name for the count data to be collected. Enter the file name, for example: PL-MMDQA where MM stands for the current month, and DO stands for the current day, and A stands for the first reading of the day. Hit <ENT> after typing in the file name. You will be prompted for the type of emission you are counting:, Alpha or Beta Enter A(lpha) or B(eta) and hit <ENT>.

You will be asked to place the standard sources (alpha or beta emitters) in the planchet holders in the detector. After this has been done, hit <ENT> to begin counting for a standard time period.

Repeat this procedure so that plateaus are measured, separately, for both alpha and beta activities.

6.2 Calculation of Operation Point

Procedure for determining the optimum high v9ltage setting.

Use the arrow keys to select Data Handling at the Main Menu. Hit <ENT> to get into the Data Handling window.

Use the arrow keys to select Operation Point Calc. in the Data Handling window. Again hit <ENT>.

The parameter table, Calculate Operation Point, will appear. The names of the • files of the last alpha and beta plateau measurements will be listed along with the plateau slopes and spillover. Hit Ctri-<ENT> to accept the entries. After confirmation, a window listing the suggested HV-Operation Point will be displayed. Make a note of this value.

Plateau measurements will have to be done periodically or if performance checks indicate measurements are •out of Control. • It is good practice to generate new plateaus whenever the P-1 0 gas tank or mylar window is changed.

~ .•.. • • I

0 1 7 • f

' ,_ I ~

, I

r

5 LANL-ER-SOP-14.01, RO 6 Page6of13.

6.3 Background Counting

Procedure for determining proper background of soil samples for the Berthold low activity counter.

Tuff-derived soil background samples for this instrument come from sand traps used in LANL water supply wells.

Tum on the Argon/Methane gas flow (P-10 counting gas) so that the float is at 1 0 units on the flow meter. Allow 30 minutes for the flow through the chamber to reach equilibrium.

Initiate the software by typing Berthold and <ENT>. Use the arrow keys to select Parameters at the Main Menu. Hit <ENT> to get into the Parameters window.

Select the Background option of the Parameters window. When the table of parameters appears, input the necessary data, and hit CTRL-<ENT> to save and store the parameters in the background file. Then select the~ option of the Parameters window. Select New parameter and use the Defaults. Enter a file name, and the suggested HV-Qperation Point that was calculated previously. Hit CTRL-<ENT> to save and store the parameters in the user file.

Use the arrow keys to select Measure at the Main Menu. Hit <ENT> to get into the Measure window.

Select the Background option in the Measure window. You will be prompted to select a user parameter file. Select the user file containing the suggested HV-Operation Point and hit <ENT>. The background measurements will automatically be saved into this file.

Insert the planchets with background soil into the planchet holders and hit <ENT> to begin counting samples for an allotted time period. The activity of the background soil samples will be automatically calculated and printed out in a hard copy. The operator can select whether to measure in counts or picocuries. 6.4 Determination of Lower Level of Detection (L0)

The Lower Level of Detection represents the lowest amount of radioactivity in a sample needed to be considered greater than background. (For this instrument one must calculate L0s for both alpha and beta detection.)

5 8 () 1

' '· ~

4, ') ...

~ ···~

, .... -. ;., . ....

·~ .....

...... . ..... '"' .~

The L0 can be calculated as follows:

LANL-ER-SOP-14.01, RO Page 7 of 13 •

L0 ... 2.71 + 4.65 (u8 )112 (see appendix A) I where, u8 is the mean measured activity for the background soil.

6.5 Calibration

Calibration for alpha and beta counting of soils is accomplished by counting samples of clean soil (the same soil that was used for the background 4 measurement) that have been spiked with known amounts of an alpha- or beta- 0 emitting radionucllde. Prior to spiking the soils, the alpha and beta background 7 count rates should be determined for the background soli to be used (as • discussed above). For optimum results, the spiked sample (standard) should ~· consist of the same material and should be placed in the planchet In the same ~-· · · configuration as the soil samples that are to be counted on a routine basis. The . .. ; radionucfides used for preparing standards should have similar decay energies · ; .• to those that one expects to encounter in the unknown soil samples. , ; . By comparing the true activity of the standard soil samples to the activity that Is , . · actually measured, the instrument will calculate the efficiency for detecting ! z; . alpha and beta emissions in each channel. These efficiencies will take into · '3-· account the geometry of the set-up, the response probability of the detector, the. type of calibration source, back scattering and self-absorption. ~ The equation for determining instrument efficiency is:

Eff. = epm/60 A

where, cpm = count rate corrected for background and half-life and A = activity in Bq of the source [Bq is Becquerels (counts/sec)) A number of alpha emissions will also be registered in the beta channel during simultaneous alpha/beta measurements. The spillover factor corrects for this •spillover" or "crosstalk" into the beta channel. This factor will be determined in the alpha ca1ibration measurement. (Spillover from the beta to alpha channels is considered negligible.)

The equation for calculating the spillover factor during the alpha calibration measurement is:splllover factor - beta count rate/alpha count rate Because the efficiency factor is calculated within the software of the instrument, the external algorithm simply converts the activity of the soil sample from counts per minute (cpm) into pCi/g (since one gram of dry soil will be counted). This conversion uses the following algorithm:

. I

' ·.~.,

:.,,-.

(SA/2.2212) • 1.012-= pCi/g

2 0 LANL-ER-SOP-14.01, RO 6

Page 8 of 13 •

where, SA • sample activity in cpm

8 ~

~- ,.·~. -'···. . . . .~- .

6.5.1

2.2212 • conversion unit to Ci

1.012 ... conversion unit to pCi

Materials

1) Berthold system

2) Spiked soil sample set in planchets

6.5.2 Operating Procedures

,

f... Use the arrow keys to select Parameters at the Main Menu. get into the Parametecs window.

":')"

~~~; Hit <ENT> to . ~ ..

Select the Calibration option of the parameters window. Select Hut Parameters and hit <ENT>.

When the table of parameters appears, Input a file name, the type of emission you are counting ((A)Ipha or (B)eta), the measurement time, and sample identification numbers. The count time depends on the application and the desired detection limits and is left to the discretion of the operator. Hit PgDn to get to the second parameter page and enter the half-lives, manufacture date and initial activities of your spiked samples. Hit CTRL-<ENT> to save and store the parameters in the parameter file.

Place the spiked samples in the planchet holders in the order that they appear in the table of calibration parameters. Generally, a spiked set of samples spans an activity range of, for example, 15- 500pCi. Use the arrow keys to select Measure in the Main Menu. Hit <ENT> to get into the Measure window.

Use the arrow keys to select Calibration in the Measure window, and hit <ENT>.

You will then be prompted to select a user parameter file. Select the file in which you stored the background measurements, hit <ENT>. (The calibration results will also be stored in this file.) Next, you will be asked to select a calibration parameter file. Select the file that was just created and hit <ENT>.

. -'' ( . r -' . ..,, ..... 4 . ,

:··,.:_

2. n 1 LANL-ER-SOP-14.01, RO t;j

Page 9 of 13 •

To begin the calibration hit <ENT>.

Repeat this process so that calibration measurements have been per1ormed for both alpha and beta sources.

6.6 Sample Preparation

The samples should be prepared according to the method developed tty the user, but preparation of the planchets should be the same as preparation of both background and standard soil sample sets. The planchets will be properly labeled to allow easy identification and tracking through the count lab. A sample label shall consist of a alpha-numeric identification number (10#). For ER samples, a unique Facility for Information, Management, Analysis, and Display (FIMAD) number is assigned to each sample. For instance, in samples from TA-1, the unique FIMAD number may be 01-1513T. Open the container holding the soil to be counted. (If the soil is moist, place a few grams of the sample in a petri dish and dry under a heat lamp before proceeding.)

Record the sample number on the bottom of the planchet using a sharpie pen. Spray the inside of the planchet with a thin film of adhesive. Place the planchet on the balance and hit the tare button of the balance (this resets balance to zero).

Add the sample to the planchet until the balance reads 1.00 ± 0.01 grams. If possible, try to remove large particles from the planchet, maintaining maximum particle size homogeneity of the sample.

Use a wooden tongue depressor to more evenly spread the sample over the surface of the planchet.

6.7 Sample Counting

The samples are placed in the detector in pre-designated locations, and counting is initiated. At the end of the count time, the data is displayed, and may be output to a printer and to a pre-specified data file.

Tum on the Argon/Methane gas flow (P-10 counting gas) so that the float ball is between 10 and 15 units on the flow meter, and allow 30 minutes for the gas flow through the chamber to reach equilibrium.

Initiate the software by typing Berthold and hit <ENT>.

Use the arrow keys to select Parameters at the Main Menu, and hit <ENT> to get into the earameters window.

t~

B n

i ., ..... ..... I

J "'

, I

r

r

•j. .,.., 0 LANL-ER-SOP-14.01 I AO ~-~

Page 10 of 13 ·:

Select the lls1u: option of the Parameters window and hit <ENT>. Select the user parameter file that contains all of your background and calibration data. Hit PgDn until you reach page 5. Use the arrow keys to move around on the

~. g !) l. ...~

I page and enter in 27.0 as the normalization factors for channels 6-10. Hit PgDn again to reach page 4, enter 27.0 as the normalization factors for channels 1-5. ,:;; This will allow you to measure activities in the units of pCi/g. Hit CTRL-<ENT> ' to save and store this information in the user parameter file. Use the arrow keys to select Measure at the Main Menu, and hit <ENT> to get into the Measyre window.

Select the Samole option from the Measure window. Select the user parameter file that contains your background and calibration results, hit <ENT>. In the table provided by the menu, input a file name and sample identification number{s} and hi1 CTRL-<ENT> to save and store the information to the file. ·· Place the planchets in the holders that correspond to the sample identifie~l "· given in the above step. Slide the sample drawer into the detector housing, and hit <ENT> to begin counting.

To view the results on the screen in pCi/g, use the arrows to select the Acti<>C.Pm option during the measurement and hit <ENT> until the activities are displayed in pCi/g. Note the calculations handled by the associated software package of the LBno correct for the background, spillover and efficiency factors that were determined in the calibration. The activities measured are those above the mean (clean soil) background activity. 6.8 Performance Check

The user should make a performance check each day to ensure the detector system is operating properly.

At the beginning of the day, turn on the argon/methane gas flow (P-10 counting . gas) so that the float ball is between 10 and 15 units on the flow meter, and allow 30 minutes for the gas flow through the chamber to reach equilibrium. Initiate the software by typing Berthold and <ENT>. Ten bare planchets, each containing 10 pCi of either alpha or beta activity, should be prepared for the performance check.

Seiect Calibration in the Parametm window and set up a New Parametem file using the same procedure that was used for the calibration measurement (see 6.5.2.3). Hit CTRL-<ENT> to save the information. Select Measure from the Main Menu. Hit <ENT> to get into the Measyre window.

., '(

5- i

LANL-ER-SOP-14.01, RO 6 Page 11 of 13 •

Select the pertormanc,Jl option in Measyre window, hit <ENT>. You will be prompted to select a user parameter file, choose the one which contains the correct calibration factors, background and HV-Operation Point. Hit <ENT>. Then you will be asked to select a calibration file, choose the file that contains the activities, half-lives, and manufacture dates for your performance check samples and hit <ENT>. Place the ten spiked planchets into the holders, and Initiate counting by hitting <ENT>.

If the counts do not exceed the maximum deviation defined by the user the

G A 0 1 7 •

•~:

I f I • system will signal •performance Check OK!• Print out copies of all Performance ·~/ Checks and compare each printout with previous printouts. If any systematic drifts are apparent or the instrument does not signal OK, notify the principal instrument operator before continuing with any sample measurements.

6.9 Quality Control (QC) Samples .. . "· Quality Control samples of known activities will periodically be counted along . ~~ ~. with unknown samples as a Quality Assurance (QA) check. The QC samples which are made from a variety of activity levels of 241Am and 137Cs on clean (background) soil, and should comprise approximately 10% of the total number of samples that will be analyzed. These QC standards should be interspersed • and run with the samples. Alternatively, pre-prepared radioactive standards embedded in planchet sized holders may be utilized as control samples.

Load the samples and QC's into the planchet holders and count the samples as described in section 6. 7 Sample Counting. 7.0 REFERENCE LITERATURE

This bibliography lists documents that relate to this procedure and that provide additional pertinent information to interested users. Currie, Lloyd A., •umits for Qualitative Detection and Quantitative Determination,• Analytical Chemistry. 40(3), 586, 1968.

Department of Energy Order 5700.68, "Quality Assurance; DOE, 1986. EG&G Ortec, •Berthold, LB770 PC 10 Channel Alpha-Beta Counter, 1st Edition• EG&G Ortec, 100 Midland Rd., Oak Ridge Tennessee, 37830. 1991. EG&G Ortec, •Maestro II A64-BI Software Operators Manual Version 1.0• EG&G Ortec. 100 Midland Rd., Oak Ridge Tennessee, 37830. 1991.

. . I > f .,. - ··~.'" :·~· .... r·. , • , .• I , • - -- • .ol '. " . -:.q .. :~· .. r., .. ·." :· ~ . ~: (/ ':"·. ·';. -.· . :t ;~ ......

LANL-ER·SOP·14.01, Page 12 of 13

Fraley. Leslie, Jr .• •Radiation Detection and Measurement • A laboratory Manual: Colorado State University Publications. Fort Colfins, co. Aug. 1991. Grant, Eugene and Leavenworth, Richard. •statistical Quality Control: McGraw Hill, NV.1972 • . •.:' . '.'

·i.

KQC.f:\&r, David C., •Radioactive Decay Data Tables: Report OOEITIC.11026, Technlcallnfotmation Center, U.S. Department of Energy, WashingtOn, D.C. 1981. · - u~s. ~partm9nt of Health Education and Welfare, •Radiological Health Handbook, • .· < B4Jr~a.p_ of Radiological Health, RockviJie, MO. 1970. · . s~o- ~ecc).flps ; ~~~;i~t~r)srl~~~e ~lbrm,l!'"· maint~nartC!' ~nd u~ of the counting system are ,- m~~h1'!!~~1!JY,:~f.l~f:Pr;tt'DAAfl~tf:L.I.ryt'n• ~~~4.!9.~;9,-~.d.~lgnee. Recorc.ts.otcf""plet · · ,: ,~,m~i~.~$Je~~~~~t~~crW~ri~·:WiE!l~9r--~r6t~~~Q:rr:~~. · .. ·.·:,~o····&,to'r~~~~~~~~l?~•·Nft::;~~· '~~ · ~reiil\at:l·eievafit'.reco~~f are tran~~e'Wto RPF~ MS· wof.' · $]. ~Tf~~~~tNTS. Attachment A • Appendix A ,,

. . ·~ .

. -;. : ..

... ' .... ~::. ~ .. t ..

::·<-

(1 pCI• 2.22 cpm)

. ;,;•

··· .... · ... •• •. \f" ·~ • •.