1. Kayzero for Windows: A complete NAA Data evaluation tool based on the orginal k0-method
R. van Sluijs, k0-ware, Heerlen, the Netherlands
A. De Wispelaere, UG, Gent, Belgium
D. Bossus, DSM, Geleen, the Netherlands
F. De Corte, UG, Gent, Belgium
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

2. k0-formula (overview) k0-Nuclear Data and Decay correction scheme’s
Irradiation and Measurement aspect: neutron self absortion in the
sample dead-time, counting time, coincidence correction etc.
k0-Nuclear Data and Decay correction scheme’s
(all published in open literature)
- Reactor parameters: f and α
(Høgdahl-convention, well described)
Detection efficiency accounting for absortion in the sample
(according to Moens)
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

3. k0-formula using Fc a: analyte m: neutron fluence rate monitor Or:
Okay, k0 method is well documented, all is clear, but is this all?
No!
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

4. k0-formula and comparator factor
With Comparator Factor Fc:
Relation between Fc and neutron fluence rate
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

5. k0-formula epicadmium ENAA
FCd,a: cadmium transmission factor for epi-thermal neutrons
Okay, k0 method is well documented, all is clear, but is this all?
No!
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

6. k0-formula: Fc benefits
Fc is proportional to e
Fc is independent of monitor element, detection efficiency (Asp is not)
Fc allows averaging
Fc gives information on:
flux gradients (several monitors in a irr. vial)
flux stability (monitor history)
Detects any gross irregularities in efficiency, data-entry, decay times
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

7. Reactor Calibration f and 
Procedure:
- Irradiate monitors
(see k0-literature, vade mecum)
- Enter Irradiation and
Measurement Data
- Press Calculate
Result:
- f & 
- plot
- uncertainty
More accurate
Solve:
Calibration methods:
Zr-Au-method
Multi-monitors: bare
Multi-monitors: Cd-covered
Multi-monitors: Cd-ratio
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

8. Reactor Calibration: f and α
Zr-Au method:
- uses only two monitors
- can be done easily with every irradiation
- optimized to reduce measurement uncertainties
Cd-ratio method:
- most accurate but takes more irradiations and measurements
-> Re-calibrate if reactor configuration changes
-> For most reactors f and α calibration frequency is very low (every 1-2 years or less)
->Calculations look difficult but are automated
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

9. Detector Calibration
Full-energy peak detection efficiency p, concept:
a) Measure reference efficiency(*) using point-sources
b) Convert p,ref to p for counting geometry/position
geo = sample geometry/position
ref = reference position
Ωp = effective solid angle
 p = full energy peak detection efficiency for photon energy p
(*) At a position true-coincidence free position
(**)See Moens et al.(1981) and Moens and Hoste (1983)
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

10. Detector Calibration
a) Measure reference efficiency p using point-sources
--> fit to efficiency curve
(several polynomes)
Fits for the 3 energy regions
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

11. Detector Calibration b) Calculate effective solid angles (’s)
Vial
Sample
Position Distance
Platform
Active
Crystal
Position 1
Position 2
Position 3
Contact Layer
Top Dead Layer
Detector
Can
Air
Layer
Source Support
Vacuum Gap
Inert Core
- Numerical Integration Program: Solang (*)
- Input needed : dimensions and material com-positions and densities of
* sample (vial)
* detector (from manufacturer)
* source support
- Fine-tuning of:
* Vacuum Gap (VG) and
* Top Dead Layer (TDL)-Thickness.
(*)For Cylindrical and concentric detector (p-type) and sources smaller than detector diameter
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

12. Detector Calibration
b) Fine tune to find vacuum gap and dead-layer thickness
Position 3
Top Dead Layer
Vacuum Gap
Active
Crystal
Position 1
Position 2
Fine Tuning:
- select detector
- select geometry per source
- enter peak area countrates
- press the button
Results in a best guess
Refine manually if needed
(instantaneous results)
Fine-tuning of VG and TDL-Thickness:
Measure true-coincidence free isotopes at different positions and optimize values VG and TDL
(See De Wispelaere et al., Proc. Int. k0 -Users Workshop, Gent Belgium, 1992)
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

13. Detector Calibration Use p for the sample on hand: - select detector
- select predifined vial
- select position
- give sample matrix composition (*)
- give sample weight (*)
- give filling height (**)
Calculated using SOLCOI for solid-angles and coincidence correction factors.
(*) Slower PC’s : Pre-calculate and use Matrix Interpolation
(fixed filling height)
(**) Fast PC’s : Direct Solid Angle Calculation
Position 1
Position 2
Position 3
Vial
Sample
Detector
Position
Distance
Platform
Active
Crystal
Position 1
Position 2
Position 3
Contact
Layer
Top Dead
Detector
Can
Air
Source Support
Vacuum Gap
Inert Core
Calibration Procedure:
- measure reference efficiency
- fit-reference efficiency
- collect all dimensions and detector material compositions and densities
- fine tune Vacuum Gap and Top Dead Layer using measurements of true-coincidence free isotopes
- calculate the effective solid angles for the reference position
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

14. Irradiation aspects
Decay correction:Saturation factor S
(including variable flux, known flux variation)
Thermal and epi-thermal selfabsorption in the sample
Ge and Gth
Burn-up correction (automatic)
152Eu, 182Ta, 198Au, 165Dy, 149Pm, 105Rh
Blank Substraction: Measurement in Irradiation Container (semi automatic)
subtraction of blank element mass including uncertainty (ascii-file per container)
U-Fission Reaction Interference :
(semi-automatic correction)
143Ce, 131I, 140La, 99Mo, 95Nb, 97mNb,
147Nd, 105Rh, 105mRh, 103Ru, 99mTc, 95Zr, 139Ba, 141Ce.
Threshold Reaction Interference :
(semi-automatic)
- User definable, reactor-channel specific data file (Nuclide, element, factor,uncertainty)
Second order Reaction Interference: (semi-automatic)
similar as threshold reactions
Flux description
WestCott convention 152(m)Eu, 168Yb, 176mLu
Fast flux interference
Primary Reaction interferences (mainly 117mSn)
Not (yet) handled in Kayzero, but covered in literature
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

15. Measurement Aspects Counting losses Variable Deadtime (automatic)
DTS (dead-time-stabilizer: fixed preset deadtime)
LFC (zero-dead-time,statistics effected, dual spectrum for correct uncertainty and limit of detection)
True-Coincidence effects
(automatic: INW program: Coincalc)
Needs extra calibration :
Peak-to-total efficiency
Spectral Background (cosmic rays and natural occurring isotopes)
Subtraction of background peaks using a background spectrum (automatic)
Energy calibration correction
(check and modify manually)
Essential for finding the correct isotopes
Peak distortion
(peak summation)
Artificial peaks from peak deconvolution of distorted a peaks
Base line calculation
(from the spectrum file)
For limit of detection calculation
Peak Area Uncertainty
Calculated from the base line and peak area
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal

16. Conclusion
The k0-method describes INAA in fysical and mathematical understandable definitions and is very suitable for computer evaluation.
With the modern tools k0-NAA can serve as a routine analysis technique
The necessary k0-method calibrations are reasonable elaborate but straight forward.
All data, formulas and other aspects of k0-INAA incorporated in Kayzero are traceable to open-literature.
As with every program: good knowledge of the k0-method and gammaspectrometry remains essential for correct and error-free use.
As for every k0-NAA-program: good knowledge of the
k0-method and gammaspectrometry remains essential for correct analysis results.
09/11/2018
4th International k0-Users Workshop,
September 11th-14nd 2005, Funchal Portugal