Mössbauer spectrometry

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LEA distributes Mössbauer sources from RITVERC for more than 15 years. But what is Mössbauer spectrometry?

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Mössbauer spectrometry is a non-destructive nuclear resonance method for studying the valence states of atoms, their chemical bonds as well as their coordination within solid phases.

This technique can be used for about 40 isotopes (the most commonly studied being 57Fe, 119Sn, 119Sb, 170Dy and 197Au), in areas ranging from atomic physics to metallurgy and physics and solid-state chemistry, nanoscience, condensed matter physics, archeology, mineralogy (the Spirit and Opportunity rovers have bring a Mössbauer spectrometer for the study of Martian soil).

Mössbauer spectrometry can be applied to all kinds of solid materials (crystalline systems, amorphous, quasicrystalline, nanocrystalline, metallic alloys, insulators, conductors, polymers) and nano structures (nanostructure powders, nanoparticles).

It uses a radioactive source to excite the studied isotopes and to observe the perturbations of their nuclear energy levels by the measurement of 3 parameters: the isomeric shift, the quadrupole separation and the hyperfine field.*

* source : article 103 of GFSM

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The active part of Mössbauer source is prepared by electrodepositing high purity carrier-free 57Co onto a thin metal backing (matrix) followed by controlled annealing process. Standard matrix is rhodium or chromium. Other matrices are available on request. All sources are carefully tested on certified equipment. Each source is supported by a Test Report with measured values of spectra parameters.

Recommended working life: 10 years

Capsule Type	D x H [mm]	d [mm]	Line Width [mm/s]	ISO Classification	Temperature range [K]	Nominal Activity*			Code
Capsule Type	D x H [mm]	d [mm]	Line Width [mm/s]	ISO Classification	Temperature range [K]	mCi		MBq	Code
Rhodium matrix
1	11.2 x 13	8	0.11 – 0.13	C54243	4.2 – 700	5 10 25 50 100	185 370 925 1850 3700		MCo7.111 MCo7.112 MCo7.113 MCo7.114 MCo7.115
2	14 x 14	8	0.11 – 0.13	C54243	4.2 – 700	5 10 25 50 100	185 370 925 1850 3700		MCo7.121 MCo7.122 MCo7.123 MCo7.124 MCo7.125
6	6 x 13	4	0.11 – 0.15	C54243	4.2 – 700	5 10 25 50 100	185 370 925 1850 3700		MCo7.161 MCo7.162 MCo7.163 MCo7.164 MCo7.165
9	4 x 14	1	0.13 – 0.15	C34243	220 – 450	5 10	185 370		MCo7.191 MCo7.192
10	6 x 17	1	0.13 – 0.15	C34243	220 – 450	5 10	185 370		MCo7.1101 MCo7.1102
Chromium matrix
1	11.2 x 13	8	0.13 – 0.16	C5443	4.2 – 700	5 10 25 50	185 370 925 1850		MCo7.511 MCo7.512 MCo.513 MCo.514
2	14 x 14	8	0.13 – 0.16	C54243	4.2 – 700	5 10 25 50	185 370 925 1850		MCo7.521 MCo7.522 MCo7.523 MCo7.524

* Tolerance: -5% to +10% | 14.41 keV photon emission efficiency ≥ 75% | Recoilless fraction : 0.75

1 & 6

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Mössbauer source active part is based on calcium stannate [CaSnO3] matrix synthesized from high specific activity (>300 mCi/g) 119^mSn radionuclide. All sources are carefully tested on certified equipment. Each source is supported by a Test Report with measured values of spectra parameters.

Recommended working life: 10 years

Capsule Type	D x H [mm]	d [mm]	Line Width [mm/s]	ISO Classification	Temperature range [K]	Nominal Activity*			Code
Capsule Type	D x H [mm]	d [mm]	Line Width [mm/s]	ISO Classification	Temperature range [K]	mCi		MBq	Code
1	11.2 x 13	10	0.38 – 0.54	C54243	4.2 – 700	2 5 10	74 185 370		MSn9.211 MSn9.212 MSn9.213
2	14 x 14	10	0.38 – 0.54	C54243	4.2 – 700	2 5 10 15	74 185 370 555		MSn9.221 MSn9.222 MSn9.223 MSn9.224
3	18 x 14	15	0.38 – 0.54	C54243	4.2 – 700	10 15 20	370 555 740		MSn9.233 MSn9.234 MSn9.235
6	6 x 13	5	0.45 – 0.54	C54243	4.2 – 700	2 5	74 185		MSn9.261 MSn9.262

* Tolerance: -5% to +10% | 23.87 keV photon emission efficiency ≥ 75% | Recoilless fraction : 0.5

1&6

2&3

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Mössbauer effect reference absorbers contain chemical substances synthesized with either enriched ⁵⁷Fe (>95%) or natural iron. The substances are uniformly dispersed in polyethylene dics of 1 mm thickness and 20 mm diameter, placed between two polyimide films in aluminium holders.

K₄Fe(CN)₆ × 3H₂O and K₂MgFe(CN)₆ exhibit unsplit narrow line in Mössbauer absorption spectra. FeC₂O₄ × 2H₂O exhibits quadrupole splitting, leading to two narrow lines in Mössbauer absorption spectrum. αFe and Fe₂O₃ exhibit magnetic hyperfine splitting, leading to six narrow lines in Mössbauer absorption spectra. All reference absorbers are carefully tested on certified equipment.

Each absorber is supported by a Test Report with measured values of Mössbauer spectra parameters.

Description	Thickness [mg ⁵⁷Fe/cm²]	Code
Description	Thickness [mg ⁵⁷Fe/cm²]	Code
Enriched iron reference absorbers
K₂MgFe(CN)₆	0.25 – 1	MRA.1.1.X*
FeC₂O₄ x 2H₂O	0.5 – 1	MRA.1.2.X*
Fe₂O₃	1 – 2	MRA.1.3.X*
α-Fe foil	3 µm	MRA.1.6
Natural iron reference absorbers
FeC₂O₄ x 2H₂O	0.13 – 0.25	MRA.2.2.X*
Fe₂O₃	0.13 – 0.25	MRA.2.3.X*
K₄Fe(CN)₆ x 3H₂O	0.13 – 1	MRA.2.4.X*
α-Fe foil	30 µm	MRA.2.6

* « X » represents the thickness of the absorber in mg 57Fe/cm². Available values of X = { 1 ; 2 ; 3 ; 4 ; 5 }, respectively for { 0.13 ; 0.25 ; 0.5 ; 1 ; 2 } mg 57Fe/cm²

Mössbauer spectrometry

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