The rapid development of X-ray astronomy has been made possible by widely deploying X-ray focusing telescopes on board many X-ray satellites. Geant4 is a very powerful toolkit for Monte Carlo simulations and has remarkable abilities to model complex geometrical configurations. However, the library of physical processes available in Geant4 lacks a description of the reflection of X-ray photons at a grazing incident angle which is the core physical process in the simulation of X-ray focusing telescopes. The scattering of low-energy charged particles from the mirror surfaces is another noteworthy process which is not yet incorporated into Geant4. Here we describe a Monte Carlo model of a simplified wide-angle X-ray focusing telescope adopting lobster-eye optics and a silicon detector using the Geant4 toolkit. With this model, we simulate the X-ray tracing, proton scattering and background detection. We find that: (1) the effective area obtained using Geant4 is in agreement with that obtained using Q software with an average difference of less than 3%; (2) X-rays are the dominant background source below 10 keV; (3) the sensitivity of the telescope is better by at least one order of magnitude than that of a coded mask telescope with the same physical dimensions; (4) the number of protons passing through the optics and reaching the detector by Firsov scattering is about 2.5 times that of multiple scattering for the lobster-eye telescope.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Q software is available from the author by request email firstname.lastname@example.org
Zhang, S. -N.: China’s first dedicated astronomy satellite: the hard x-ray modulation telescope (HXMT). AAS 41, 474 (2009)
Yuan, W., Zhang, C., Feng, H., et al.: Einstein Probe — a Small Mission to Monitor and Explore the Dynamic X-ray Universe. La Sapienza University, Rome, Italy (2014)
Zhao, D., Zhang, C., Yuan, W., et al.: Ray tracing simulations for the Wide-field X-ray Telescope of the Einstein Probe mission based on Geant4 and XRTG4. SPIE, 9144 (2014)
Yuan, W., Osborne, J.P., ZHang, C., Willingale, R.: Exploring the Dynamic X-ray Universe: Scientific opportunities for the einstein probe Mission[J]. J. Spat. Sci. 36(2), 117–138 (2016)
Wolter, H.: Spiegelsysteme streifenden Einfalls als abbildende Optiken für röntgenstrahlen. AnP 445, 94–114 (1952)
Angel, J. R. P.: Lobster eyes as X-ray telescopes. ApJ 233, 364–373 (1979)
Agostinelli, S., 127 colleagues: GEANT4—A simulation toolkit. NIMA 506, 250–303 (2003)
Fraser, G. W., Brunton, A. N., Lees, J. E., et al.: X-ray focusing using square-pore microchannel plates First observation of cruxiform image structure. NIMPA 324, 404–407 (1993)
Benkhoff, J., van Casteren, J., Hayakawa, H., et al.: BepiColombo—Comprehensive exploration of Mercury: Mission overview and science goals. Planet. Space Sci. 58, 2–20 (2010)
Fraser, G.W., Carpenter, J.D., Rothery, D.A., et al.: The mercury imaging X-ray spectrometer (MIXS) on bepicolombo. Planet. Space Sci. 58, 79–95 (2010)
Buis, E. J., Vacanti, G.: X-ray tracing using Geant4. NIMA 599, 260–263 (2009)
Short, A. D., Ambrosi, R. M., Hutchinson, I. B., et al.: Performance of the Swift X-ray Telescope (XRT) Mirror/Detector Combination. AIPC 662, 511–513 (2003)
Spaan, F. H. P., Willingale, R.: The point spread function of silicon pore x-ray optics. SPIE, 7011 (2008)
Martindale, A., 18 colleagues: The Mercury Imaging X-ray Spectrometer: optics design and characterisation. SPIE 7441, 744117 (2009)
Willingale, R., Fraser, G. W., Brunton, A. N., et al.: Hard X-ray imaging with microchannel plate optics. ExpA 8, 281–296 (1998)
Prigozhin, G. Y., Kissel, S. E., Bautz, M. W., et al.: Radiation damage in the Chandra x-ray CCDs. SPIE 4012, 720–730 (2000)
Dichter, B. K., Woolf, S.: Grazing angle proton scattering: effects on chandra and xmm-newton x-ray telescopes. ITNS 50, 2292–2295 (2003)
Turner, M.: A magnetic diverter for Charged Particles on XEUS ESA document SCI-SA/AP/06/0412cv (2006)
Prepared by the XMM-Newton Community Support Team with contributions from the entire XMM-Newton Science Operations Centre Team, XMM-Newton Users Handbook, Issue 2.13, 20.07. 2015
Willingale, R.: An electron diverter for the Swift Telescope, XRA study note XRT-LUX-RE-011/1 University of Leicester (2000)
Burrows, D. N., Hill, J. E., Nousek, J. A., et al.: The Swift X-Ray Telescope. SSRv 120(3-4), 165–195 (2005)
Lei, F., Nartallo, R., Nieminen, P., et al.: Update on the use of geant4 for the simulation of Low-Energy protons scattering off X-Ray mirrors at grazing incidence angles. ITNS 51, 3408–3412 (2004)
Firsov, O. B.: Reflection of fast ions from a dense medium at glancing angles. Sov. Phys. Dokl. 11, 732 (1967)
Nartallo, R., Daly, E., Evans, H., et al.: Low-angle scattering of protons on the XMM-newton optics and effects on the on-board CCD detectors. ITNS 48, 1815–1821 (2001)
Petrov, A.N., Grigoryan, O.R., Panasyuk, M.I.: Energy spectrum of proton flux near geomagnetic equator at low altitudes. AdSpR 41, 1269–1273 (2008)
Hiroshi, T., Masaru, M., Shiro, U., et al.: Cosmic-ray background simulation for the CCD camera (SSC) of the MAXI mission onboard the International Space Station. Proc. SPIE 4851, 993 (2003)
Zhao, D., Cordier, B., Sizun, P., et al.: Influence of the Earth on the background and the sensitivity of the GRM and ECLAIRs instruments aboard the Chinese-French mission SVOM. ExpA 34, 705–728 (2012)
Campana, R., Feroci, M., Del Monte, E., et al.: Background simulations for the Large Area Detector onboard LOFT. ExpA 36, 451–477 (2013)
Miyaji, T., Ishisaki, Y., Ogasaka, Y., et al.: The cosmic X-ray background spectrum observed with ROSAT and ASCA. A&A 334, L13–L16 (1998)
Barthelmy, S. D., Barbier, L. M., CUMMINGS, J. R., et al.: The Burst Alert Telescope (BAT) on the Swift MIDEX mission. SSRv 120, 143–164 (2005)
Voges, W., 19 colleagues: The ROSAT all-sky survey bright source catalogue. A&A 349, 389–405 (1999)
This work is supported by the Strategic Priority Research Program on Space Science, the Chinese Academy of Sciences, Grant No. XDA04061100, the programs of National Natural Science Foundation of China under the Grant No.11403055, No.11203043 and No.11427804, China Post-doctoral Science Foundation under the Grant No.2014M561068, and the Young Researcher Grant of National Astronomical Observatories, Chinese Academy of Sciences.
About this article
Cite this article
Zhao, D., Zhang, C., Yuan, W. et al. Geant4 simulations of a wide-angle x-ray focusing telescope. Exp Astron 43, 267–283 (2017). https://doi.org/10.1007/s10686-017-9534-5
- X-ray telescope
- Lobster-eye optics
- Scattering of charged particles