Laser Desorption Time‐of‐Flight Mass Spectrometer LASMA

Managadze, G.1; Wurz, P.2; Chumikov, A.1; Luchnikov, K.1

1 RAS Space Research Institute, RUSSIAN FEDERATION; 2 University of Bern, SWITZERLAND

managa@iki.rssi.ru

luchnikov@iki.rssi.ru

Science and Challenges of Lunar Sample Return

ESTEC, 18-19 Feb 2014

Introduction

Our LA TOF-MS perform high accuracy

elemental and isotopic analysis of

solids in situ. High spatial resolution

and ability to raster the sample surface

allows to study sample composition

both averaged and locally. This robust

instrument is ideal both for rapid

sample screening and for thorough

investigations.

The latest modification of the

instrument for ExoMars-2018 mission

named ABIMAS is in the early stage of

development.

LASMA is developed in close

collaboration with University of Bern.

Our instruments

LIMA-D

LASMA-Phobos, right

LASMA-L (LUNA-Globe / LUNA-Resource)

ABIMAS (ExoMars-2018), bottom

Scheme of the instrument

MCP Detector Assembly

Sample under Investigation

Ion Lens

Laser Head

ADC

Reflectron

Drift Tube +

OP-Amp

Reflectron & Detector Performance

Mass range 1-250 (1000) Da

Resolution (FWHM) 250-550

Relative sensitivity 10 ppm / one shot

One spectrum dynamic range 104

* Instrument allows to analyze ions in a broad range of masses. The mass-spectra of elemental composition are limited by 250 Da but range can be greatly expanded.

Resolution depends on the type of target and plasma formation conditions. Detector and amplifier do not hinder to achieve better resolution in high mass spectrum region

Laser Ion Source

Wavelength 1064 nm

Pulse repetition rate 0.1-1 Hz

Maximum irradiance 8.3*1010 W/cm2

Beam diameter at target (D80) <35 um

Spatial resolution approx. 35x35x1 um

Pulse length (FWHM) <8 ns

Pulse to pulse energy instability <10%

Technical Characteristics

Interface RS-485

Spectrum size 32 Kb

Internal memory up to 128 Mb

Power consumption 5-20 W

Dimensions 254x206x130 mm / 325 x 237 x 220 mm*

Mass 2.8 kg / 5.0 kg*

Operation pressure 10-6 torr

Operation temperature -20 … +50

Storage temperature -40 … +60

* With vacuum chamber and turbomolecular pump

Co-axial configuration of the instrument allows sample imaging while the image sensor is co-planar with sample. Though imaging is not currently implemented.

Lab Measurements

Left: NIST SRM C1154a one-shot spectrum, 1-shot sensitivity ≈ 10 ppm

Right: C-Ti-Nb-W alloy sample, W spectrum region, RFWHM ≈ 500

JSC-1 Moon Regolith Simulant Spectrum

Thin surface films and dust analysis

<<< Mass spectrum of

fused alumina sample

contaminated surface

Organic compounds analysis

IR-1061 laser dye mass

spectrum

661, 662, 663 peaks are

fairly well resolved.

K. A. Luchnikov, G. G. Managadze, P. Wurz et. al., “Polyatomic Ions Mass Analysis Using Compact Laser Desorption/Ionisation TOF-MS”, The Fourth Moscow Solar System Symposium

Sample loading and manipulator interaction

• Carrousel allows to load up to 11 samples

• One cell is reserved for reference calibration sample

• Instrument requires dispersed sample with the largest fraction not exceeding 2 mm in diameter

• Excess of regolith is removed and the surface is flattened before analysis internally.

Scientific objectives

LA TOF MS instrument can provide crucial information about:

• Elemental composition of regolith (before delivery to the Earth)

• Trace (minor) elements abundance (Li, Sc, Co, Zr, Ba, …, W,…)

• Inhomogeneity of the composition

• Processes of space weathering, interaction with cosmic rays and meteorites

• History of surface formation

• Surface dust composition

Thank you for your attention