University of Houston • University of Houston-Clear Lake • ISSO Annual Report Y2004 • 80-81
Use of FLUKA in the Analysis of the Mars Odyssey MARIE Experiment
Abstract--UH and NASA physicists have made significant post launch improvements to the calibration of the MARIE data by simulating the response of the instrument to energetic protons using the Monte Carlo radiation transport code FLUKA.
MARIE is a charged particle telescope aboard Mars Odyssey designed to detect energetic nuclei. The purpose of the instrument is to characterize the radiation environment at Mars as an aid in planning eventual manned missions to the planet. In addition, the data--if properly calibrated--is also useful in the study of the transport of galactic cosmic rays and solar energetic particles in the inner heliosphere. Unfortunately, MARIE received relatively little calibration before it was launched; in order to completely calibrate the data from MARIE, we must thus rely on detailed simulations of the transport of particles through the instrument.
Results
In order to calibrate the MARIE data, we are using the Monte Carlo radiation transport
code FLUKA, which is one of the most powerful and up to date codes of its type. FLUKA
contains detailed prescriptions for the continuous energy loss of a charged particle as it
travels through matter, as well as the nuclear reactions that may occur within the
material that the particle is traversing.1,2 The first step in the simulation
process is to construct a detailed geometric and compositional model of the instrument as
well as the spacecraft. An example of the FLUKA geometry for MARIE and Odyssey is shown in
Fig. 1.
Figure 1. A schematic view of the simulation geometry of MARIE and other major elements of Mars Odyssey. MARIE is visible in this figure as the small box near the left-center of the picture. The smaller elements visible inside MARIE are the detectors.
MARIE consists of a stack of silicon detectors of different thickness. As energetic charged particles traverse the detectors, they deposit energy in the detectors; the amount of energy deposited depends on both the kinetic energy of the particle as well as its charge. Each silicon detector returns a measured voltage that is proportional to the energy deposited in that detector; we calibrate the data by fitting a relation between the observed data and simulated data. A plot of raw data from two of MARIE's detectors is shown in Fig. 2. Simulated data for the same set of detectors is shown in Fig. 3. Note the excellent correspondence between the actual and simulated data. With these simulations we have been able to significantly improve the calibration of the MARIE data.
Figure 2. Raw data for a pair of MARIE detectors. Voltages have been converted to an arbitrary scale by an analog to digital converter (ADC). Several features are visible on the plot; the diagonal line from upper right to lower left is due to higher energy nuclei of different species, the line marking the greater than symbol (>) is due to low energy protons, and the spray of points that covers the diagram is due to particles that have experienced a nuclear reaction in one or other of the detectors.
Figure 3. Simulations of low energy protons for the same pair of detectors plotted in Fig. 2. Note the excellent correspondence between the observed and simulated data.
References
1A. Fasso, A. Ferrari, and P. R. Sala, "Electron-Photon Transport in
FLUKA: Status," Proc., MonteCarlo 2000 Conference, Lisbon, Oct. 23-26, 2000,
(2001): 159-64.
2A. Fasso, A. Ferrari, J. Ranft, and P. R. Sala. "FLUKA: Status and
Prospective for Hadronic Applications," Proc., MonteCarlo 2000 Conference,
Lisbon, Oct. 23-26 2000, (2001): 955-60.
Publications and Presentations
Andersen, V., K. Lee, L. Pinsky, W. Atwell, T. Cleghorn, F.
Cucinotta, P. Saganti, R. Turner, and C. Zeitlin. "Monte Carlo
Simulation of the Response of the MARIE Instrument," Proc., 28th
International Cosmic Ray Conference (2003.): 2113-16.
Andersen, V. F. Ballarini, G. Battistoni, M. Campanella, M. Carboni, F. Cerutti, A. Empl,
A. Fasso, A. Ferrari, E. Gadioli, M. V. Garzelli, K. Lee, A. Ottolenghi, M. Pelliccioni,
L. S. Pinsky, J. Ranft, S. Roesler, P. R. Sala, and T. L. Wilson. "Progress Towards a
FLUKA-Based Simulation Tool Aimed at the Evaluation of Space Radiation Environments,"
in Intersections of Particle and Nuclear Physics, 8th Conference CIPANP2003. AIP
Conference Proc., Vol. 698.
Andersen, V., F. Ballarini, G. Battistoni, M. Campanella, M. Carboni, F. Cerutti, A. Empl,
A. Fasso, A. Ferrari, E. Gadioli, M. V. Garzelli, K. Lee, A. Ottolenghi, M. Pelliccioni,
L. S. Pinsky, J. Ranft, S. Roesler, P. R. Sala, and T. L. Wilson. "The Fluka Code for
Space Applications: Recent Developments," Advances in Space Research 34.6
(2004): 1302-10.
Fasso, A., A. Ferrari, S. Roesler, J. Ranft, P. R. Sala, G.
Battistoni, M. Campanella, F. Cerutti, L. De Biaggi, E.
Gadioli, M. V. Garzelli, F. Ballarini, A. Ottolenghi, D.
Scannicchio, M. Carboni, M. Pelliccioni, R. Villari, V.
Andersen, A. Empl, K. Lee, L. Pinsky, T. Wilson, and N.
Zapp. "The FLUKA Code: Present Applications and Future Developments," Computing
in High Energy and Nuclear Physics (2003).
Zeitlin, C., T. F. Cleghorn,. F. A. Cucinotta, P. Saganti, V. Andersen, T.
Lee, L. S. Pinsky, and R. Turner. "The Martian Radiation Environment
Experiment--Results and Status," American Geophysical Union, Spring Meeting,
Montreal, Canada, April 17-21 2004.
Funding and Proposals
"Analysis of Data from the Mars ’01 MARIE Experiment," Aug. 1,
2001-July 31, 2002, NAG9-1347, $25,894.
"Determining the Radial Dependence of Particle Intensities from Coronal Mass
Ejections," Jan. 1, 2002-Dec. 31, 2003, ARP, $103,000.
Student Report
Lee, K., doctoral dissertation in progress; talks and publications listed under
Publications and Presentations, above, Jan. 16, 2001-present; Funding obtained: $25,894,
(See NAG9-1347, $25,894).
PDF (567KB)
Table of Contents
Institute for Space Systems Operations - Y2004 Annual
Report
Copyright © 2005
|
