Temperature Dependence and Sampling Depth

For measurements on planetary surfaces, the instrument has to meet special requirements. In the case of Mars, MIMOS II is able to work at temperatures as low as — 140°C and an average atmospheric pressure of 7 mbar of CO2 [36,40,47, 52-55]. 

MIMOS II has three temperature sensors one on the electronics board and two on the SH. One temperature sensor in the SH is mounted near the internal reference absorber, and the measured temperature is associated with the reference absorber and the internal volume of the SH. The other sensor is mounted outside the SH at the contact ring assembly. It gives the approximate analysis temperature for the sample on the Martian surface. This temperature is used to route the Mossbauer data to the different temperature intervals (maximum of 13, with the temperature width software selectable) assigned in memory areas. Shown in Fig. 3.21 are the data of the three temperature sensors taken on Mars (rover Opportunity at Meridiani Planum) in January 2004 between 12 10 PM on Sol 10 (10 Martian days after landing) and 11 30 AM on Sol 11. The temperature of the electronics board inside the rover is much higher than the temperatures inside the SH and the contact plate sensor, which are nearly identical and at ambient Martian temperature. 

An example of a simulated overnight experiment on Mars is shown in Fig. 3.22 for eight temperature intervals using the Compositional Calibration Target (CCT made out of magnetite rock slab) on the rover as the target. In the case of contact-ring temperature sensor failure, the internal temperature sensor would be used (software selectable). 

Mossbauer spectra of layered samples are influenced by various parameters, such as the thickness of the layers, the density of the sample, and its elemental 

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