Improvement of bulk analysis of environmental samples by using a multiple collector ICP-MS IAEA Safeguards Symposium - Vienna Amélie Hubert, Anne-Claire Pottin and Fabien Pointurier 20-24 OCTOBER 2014
AIMS OF ENVIRONMENTAL SAMPLING Checking the consistency of the Nuclear Material s legal owner declaration without having access to the nuclear material o Only isotopic measurements allow to discriminate between the different origins and purposes of nuclear material detected in the samples. o Considering the low amount of and/or contained in the sample, very high sensitive techniques are required. Cotton swipes IAEA Safeguards Symposium 20-24 october 2014 PAGE 2
SAMPLE ANALYSIS There are two ways of analyzing cotton swipes: bulk analysis ( and have a «unique» average isotopic signature, and are quantified) particles analysis (particles are extracted and the isotopic signature of each particle is measured individually) CEA/DAM-DIF is part of the IAEA s NWAL (Network of Analytical Laboratories) for bulk analysis and particle analysis of environmental samples, in support of the IAEA s SG program since 2001. IAEA Safeguards Symposium 20-24 october 2014 PAGE 3
Protocol followed at CEA/DAM-DIF for bulk analysis Swipe treatment and digestion of the whole sample Dry ashing to eliminate organic compounds in furnace at 550 C. Acid digestion for total Separation, concentration, and purification of and dissolution of the are performed by ion sample. Addition of exchange tracers for quantification. chromatography. IAEA Safeguards Symposium 20-24 october 2014 PAGE 4
Protocol followed at CEA/DAM-DIF se of Inductively Coupled Plasma Mass Spectrometry (ICP-MS). ICP-MS X-Series II ICP-MS Element XR ranium measurements Quadrupole ICP-MS, single collector S-option to enhance sensitivity: additional pump to reduce vacuum in the interface Sensitivity of 500,000 counts.s-1 per ppb of 235 /238 RSD as low as 0.2% Measurement of 236/238 isotopic ratio below 10-6 Plutonium measurements, Element XR Sector field ICP-MS, single collector Jet interface High sensitivity of 60 106 counts.s-1 per ppb of (X120 compared to ICP-QMS) Strong peak tail effect (+30 ppm at M-1) and hydrides (+20 ppm at M+1). IAEA Safeguards Symposium 20-24 october 2014 PAGE 5
OVERVIEW OF THE NEPTNE PLS AT CEA/DAM-DIF Description of the system Differents introduction systems (Cyclonic chamber or desolvating system) Large interface pump (to enhance the sensitivity) Array of 15 detectors (10 Faraday cups, 3 secondary electron multipliers (SEM) and 2 compact discrete dynode (CDD)) 2 ion energy filters (RPQ) 1011 and 1012 Ohms resistor amplifiers IAEA Safeguards Symposium 20-24 october 2014 PAGE 6
SENSITIVITY OF THE INSTRMENT FOR TRACE ANALYSIS IAEA Safeguards Symposium 20-24 october 2014 PAGE 7
SENSITIVITY OF THE INSTRMENT FOR TRACE ANALYSIS IAEA Safeguards Symposium 20-24 october 2014 PAGE 8
CONFIGRATIONS OF THE DETECTORS The configuration of the detectors depends on the concentration of the radionuclides in the solution. Possibility to adapt the resistor amplifier of the Faraday cups. Attached H4 H3 H2 238 H1 C/ IC1-C (SEM) +filter 236 L1 235 L2* 234 L3 IC5 (CDD) L4 IC1-B (SEM) +filter L5*/ IC2 (SEM) IC3 (SEM) +filter IC4 (CDD) Fixed 238 244 236 235 234 233 242 241 240 239 * se of 1012 Ω amplifier IAEA Safeguards Symposium 20-24 october 2014 PAGE 9
SET P OF THE DETECTORS FOR P ISOTOPES MEASREMENT AT TRACE LEVEL SEM magnet IC5 (CDD) 244 L4 IC1-B (SEM) +filter 242 L5*/ IC2 (SEM) 241 IC3 (SEM) +filter 240 IC4 (CDD) variable multicollector zoom optics amplifier housing 239 plasma interface and ion transfer optics ESA Figure from Thermo torch Adjustement of the position of IC5 and of dispersion lens of the zoom optics IAEA Safeguards Symposium 20-24 october 2014 PAGE 10
DETECTION CAPACITY OF THE INSTRMENT FOR TRACE ANALYSIS Main limitations of the SFICP-MS (Element-XR) Analysis with MC-ICP-MS (Neptune Plus, ThermoFisher) Abundance sensitivity (tail effect at M-2) : around 5 ppm (no possibility to measure 236/238 below 10-6) Abundance sensitivity (tail effect at M-2) : around 140 ppb Multiple collector with large dynamic range Single collector Adjustement to the isotopic composition and the concentration of the sample With energy filter Atomic mass unit 236 238 IAEA Safeguards Symposium 20-24 october 2014 PAGE 11
EXEMPLE: PRECISION AND ACCRACY FOR RANIM MAJOR ISOTOPES IAEA Safeguards Symposium 20-24 october 2014 PAGE 12
EXEMPLE: PRECISION AND ACCRACY FOR RANIM MINOR ISOTOPES IAEA Safeguards Symposium 20-24 october 2014 PAGE 13
EXEMPLE: PRECISION AND ACCRACY FOR RANIM MINOR ISOTOPES IAEA Safeguards Symposium 20-24 october 2014 PAGE 14
PERSPECTIVES After 4 months of implementation, the MC-ICP-MS is now operational for the analysis of bulk environmental samples. It is extremely sensitive for ultra-trace analyses. The accuracy and the reproducibility of the measurements have been increased (reproducibility of 0.05% with the MC-ICP-MS on the determination of the 235/238 compared to 0.6% with the ICP-QMS). ranium and plutonium can now be analysed on the same instrument. The intrument will also be used for the measurement of Th and Pa for age determination. The large dynamic range of the detectors allows to analyse a wide range of samples. IAEA Safeguards Symposium 20-24 october 2014 PAGE 15
PAGE 16 IAEA Safeguards Symposium 20-24 october 2014 CEA, DAM, DIF, F-91297 Arpajon, France