Use of 10$^{12}$ and 10$^{13}$ ohm resistor amplifiers for uranium isotopic measurements by TIMS and MC-ICPMS

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HAL Id: cea-02439460

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Use of 10

12

_{and 10}

13

_{ohm resistor amplifiers for uranium}

isotopic measurements by TIMS and MC-ICPMS

H. Isnard, M. Aubert, A. Nonell, F. Chartier

To cite this version:

H. Isnard, M. Aubert, A. Nonell, F. Chartier. Use of 1012_{and 10}13_{ohm resistor amplifiers for uranium}

isotopic measurements by TIMS and MC-ICPMS. Goldschmidt 2016 - International conference on geochemistry and related subjects, Jun 2016, Yokohama, Japan. �cea-02439460�

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27 July 2016, Goldschmidt 2016 Yokohama

14 JANVIER 2020 CEA | 10 AVRIL 2012| PAGE 1

USE OF 10

AND 10

OHM RESISTOR

AMPLIFIERS FOR URANIUM ISOTOPIC

MEASUREMENTS BY TIMS AND

MC-ICPMS

ISNARD H., AUBERT M., NONELL A., CHARTIER F;

CEA Saclay, DEN / DANS / DPC / SEARS / Laboratoire de

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URANIUM ISOTOPE RATIOS

NUCLEAR DOMAIN

Isotopic characterization at all steps of nuclear fuel cycle

Validation of neutronic calculation codes

IAEA safeguards

Nuclear forensics. Source discrimination and datation (U-Th)

Certification of nuclear materials (metrology)

EARTH SCIENCE

Datation: U-Pb, U-Th

Sources discrimination: paleoclimatology, hydrology Study of isotopic fractionation (235_U/238_{U fractionation)}

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ADVANTAGES OF 10

ET 10

RELATIVE TO SEM

FOR MEASUREMENTS OF MINOR U ISOTOPES

14 JANVIER 2020 | PAGE 3

Minor uranium isotope ratio measurements (

234

_{U and}

236

_U)

Isotopic ratios determined on MC instruments (TIMS, MC-ICPMS). Minor isotopes are generally measured SEM or Daly electrode coupled to a photomultiplier

Drawbacks: - Many settings must be performed (linearity, dead time, gain between SEM or Daly electrode and Faraday cup)

- Limited time of life

Advantages of 10

12

_{et 10}

13

_{ohm amplifiers}

Increased by a factor 10 to 100 relative to 1011 ohm amplifier  the _{signal to}

noise ratio is increased by a factor 3 to 10

Easy calibration, flexibility (choice of the amplifier resistor considering the application)

1012 _{ohm: developed in 2007 (Tuttas et al.). Applications: K, Nd, Pb, Hf, S, W.}

Measured signals in the order of few mV but limited below the mV.

1013 _{ohm: developed in 2013-2014. Applications: Nd, Pb, Sr. Signals lower than}

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MINOR URANIUM ISOTOPE RATIO MEASUREMENTS

Systematic study of certified reference materials (IRMM)

TIMS (Triton Plus) and MC-IPMS (Neptune Plus) measurements

Choice of the ohm resistor considering the atomic abundance of 234_{U and}236_U

Internal normalisation 235_U/238_{U to better compare the performances of 10}12 _and

1013 _{ohm resistors for low signals}

Gain calibration of 1013 _{relative to 10}11 _{ohm resistors performed using an Nd}

isotopic standard  reproducibility around 40 ppm

234

_U

235

_U

236

_U

238

_U

IRMM 183

0,0019688 % 0,32049 % 0,0147858 % 99,66276 %

IRMM 184

0,0052752 % 0,72096 % 0,000012356 % 99,2738 %

IRMM 185

0,0175913 % 1,96574 % 0,00028316 % 98,01639 %

IRMM 186

0,028479 % 2,98430 % 0,0032217 % 96,98399 %

IRMM 187

0,036935 % 4,5167 % 0,0068683 % 95,4395 %

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10 ET 10

OHM TIMS MEASUREMENTS

Details of measurement procedure by static multicollection

238_{U signal between 3 and 4 volts. Number of}_{measurement cycles = 80}

(integration time = 16.777 secondes).

Abundance sensitivity corrections: measurements of half masses (233.5 and 234.5 for 234 mass and 235.5 and 236.5 for 236 mass measured on the same ohm resistors)

L2

L1

Ax

H1

H2

1012_ou 1013 10 11 ₁₀12_ou 1013 10 11 ₁₀11 Seq. 1 234

_U

235

_U

236

_U

₂₃₇

238

_U

Seq. 2 233.5 234.5 235.5 236.5 237.5 Seq. 3 234.5 235.5 236.5 237.5 238.5 | PAGE 5

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10

12

_{ET 10}

13

_{OHM TIMS MEASUREMENTS}

Internal

reproducibility obtained according to the ion beam intensity

Signals between 0.08 and 0.2 mV (5000 to 12500 on SEM) Comparison of measurements 1012_{, 10}13 _{ohm and SEM}  IRMM 183 et 184

12 500 cps

10

12

ohm

10

13

_ohm

5000 cps

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Measurement procedure by dynamic multicollection with axial SEM (+

electrostatic filter)

238_{U signal between 3 and 4 volts. Number of}_{measurement cycles = 40}

(integration time = 16.777 secondes for 234_{U and}236_{U and 8.839 secondes for}235_U

and 238_U)

Abundance sensitivity corrections: measurements of half masses (235.5 and 236.5 for 236 mass measured on SEM)

Internal correction of Gain F/SEM gain: 235_{U measured on SEM (Seq. 2) and}

Faraday (Seq. 4)

TIMS: COMPARISON 10

, 10

, SEM (5000 to 12 500

cps)

L2

L1

_(SEM)

Ax

H1

H2

H3

Seq. 1 234

_U

238

_U

Seq. 2 235

_U

238

_U

Seq. 3 233.5 234.5 235.5 Seq. 4 234

_U

235

_U

236

_U

238

_U

Seq. 5 234.5 235.5 236.5 | PAGE 7

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0,0000524 0,0000526 0,0000528 0,0000530 0,0000532 0,0000534 0,0000536 0,0000538 0,0000540

TIMS: COMPARISON 10

12

_{, 10}

13

_{, SEM (5000 à 12 500}

cps)

0,0000191 0,0000193 0,0000195 0,0000197 0,0000199 0,0000201 0,0000203

IRMM 184

IRMM 183

2 34

U

/

2 38

U

2 34

U

/

2 38

U

SEM/F

0.2% 0.2% 0.2% 0.2%

0.71%

0.21%

0.26%

0.64%

0.21%

1.20%

0.08%

10

12

_ohm

SEM

_SEM

10

13

_ohm

0.23%

0.10%

0.28%

STD %

5700 cps = 0.09 mV 10 300 cps = 0.17 mV | PAGE 8

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MC-ICPMS MEASUREMENTS

Measurement procedure by multicollection

238_{U signals between 4 and 45 volts. Number of}_{measurement cycles = 30}

(integration time = 8.4 secondes)

Abundance sensibility corrections: measurement of half masses (233.5 and 234.5 for 234 mass and 235.5 and 236.5 for 236 mass measured on the same ohm resistors)

Measurements of the certified isotopic standard IRMM 184 at different signals measured on the 234_{U mass on 10}12 _{ohm resistor amplifier}

L2

L1

Ax

H1

H2

1012 ₁₀11 ₁₀11 ₁₀11 ₁₀11 Seq. 1 234

_U

235

_U

236

_U

₂₃₇

238

_U

Seq. 2 233.5 234.5 235.5 236.5 237.5 Seq. 3 234.5 235.5 236.5 237.5 238.5 | PAGE 9

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External

reproducibility and

accuracy

on the IRMM 184 standard

Measurements of 234, 235 et 238 on Faraday cups

Method validation : accuracy < 0,1% (signal of 2.3mV signal on 234_U)

MC-ICPMS MEASUREMENTS

0,0000526 0,0000528 0,0000530 0,0000532 0,0000534 0,0000536 0,0000538 0,0000540 0,0000542 0,0000544

IRMM 184

2 34

U

/

2 38

U

0.82%

0.41%

0.34%

0.26%

0.11%

0.15%

0.06%

0.2 mV 0.6 mV 0.7 mV 0.9 mV 1.1 mV 1.7 mV 2.3 mV | PAGE 10

Analysed quantity

100 ng

800 ng

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CONCLUSIONS AND PERSPECTIVES

14 JANVIER 2020 | PAGE 11

New analytical procedures for the determination of uranium isotope ratios by TIMS with measurements of 234 and 236 uranium isotopes on 1012 Ω et 1013 Ω resistors

Flexibility

Robustness in comparison to SEM measurements

Reproducibilitybetter than those obtained by SEM for signals > 12 500 cps (=0.2 mV)

MC-ICPMS measurements and measurements of 234 isotope on 1012 Ω

Necessity to take into account of baseline corrections and abundance sensibility corrections

Reproducibility obtained lower than 0,1% for signals in the order of few mV

Perspectives

MC-ICPMS measurements of uranium minor isotopes on 1013 Ω

Development of coupling between separative techniques and MC-ICPMS MC with measurements of uranium minor isotopes on 1012Ω

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| PAGE 12

CEA | 10 AVRIL 2012 DEN

DPC SEARS

Commissariat à l’énergie atomique et aux énergies alternatives Centre de Saclay| 91191 Gif-sur-Yvette Cedex

T. +33 (0)1 69 08 80 79|F. +33 (0)1 69 08 54 11

Etablissement public à caractère industriel et commercial |R.C.S Paris B 775 685 019