PoS(ICRC2015)137 http://pos.sissa.it/ ce. the effect of radiation on elec- ty - Technology Demonstration tension to 5 years and TDP8 is ticular for the case of Solar En- lly designed to characterise the d on the X panel of the Alphasat the results from ground tests. The flight model together with the esti- (SVD) method. Results for Proton ransceivers) in geostationary orbit. iod. On ground, correlation between the unfolding of MFS channel counts ute in Switzerland in 2010. The main ability. A full Geant4 simulation with /13/NL/AK and 4000112863/14/NL/HB (the last iods of maximum solar activity of solar nal Spectrometer (MFS) and the CTTB shed. Before launch, MFS was submit- tículas, Lisbon, Portugal ox 17214, GR-10024 Athens, Greece. ive Commons Attribution-NonCommercial-ShareAlike Licen Technology Centre, Noordwijk, The Netherlands & † , P. Gonçalves ∗ [email protected] Speaker. This work has been supported by ESA/ESTEC contracts 3-14025 mation of particle energy resolution and identification cap spectra measured with the MFS inergetic GEO Particle will (SEP) be events registered presented, in in 2014 par during per purpose was the validation and calibration of the MFS proto- the MFS in-flight configuration was builtfull and detector used simulation to has validate proved to beinto a particle valuable spectra tool for based on a Single Value Decomposition cycle 24. ted to proton and electron beam tests at Paul Scherrer Instit radiation environment and radiation effects can be establi Payload 8) integrates the radiation monitor(Component Multi-Functio Technology Test Bed). Thesatellite two as units are a installe hostedSpace payload. Radiation environment MFS while is CTTBtrical was an components built instrument (GaN to transistors, specifica monitor MemoriesThe and mission Optical lifetime T of AEEF/TDP8expected is to 3 be years acquiring with scientific data possible during ex the whole per The AEEF-TDP8 (ESA Alphasat Environment and Effects Facili ∗ † Copyright owned by the author(s) under the terms of the Creat c in the framework of the HERMES project). L. Arruda SEP Protons in GEO with theSpectrometer ESA MultiFunctional E-mail: I. Sandberg, I. A. Daglis Institute of Accelerating Systems and Applications, P.O. B Laboratório de Instrumentação e Física Experimental de Par A. Marques, J. Costa Pinto, A. Aguilar,EFACEC, Moreira P. Marinho, da Maia, T. Portugal Sousa A. Menicucci, P. Nieminen ESA European Space Research The 34th International Cosmic Ray Conference, 30 July- 6 August, 2015 The Hague, The Netherlands PoS(ICRC2015)137 is 1 /s at en- L. Arruda 2 5 W), easily in- < , equally spaced and 2 particles/cm 7 ) in a stack of 11 silicon 10 dx × / d in the top of the stack. The f 1 dE d is in geosynchronous (GEO) nvironment including the heart to 900 mm y radiation effects by employing (MFS), whose development was 2 e (TDP8) was the ESA Alphasat 3 kg), low-power ( cles out from the field of view which ided four Technology Demonstration cs drives technology designs that are antalum) with increasing thicknesses s two experiments: Component Tech- y loss ( < r Particle Events (SPE). Moreover, the llustrates the MFS apparatus. Its particle ustry. Alphabus [1] [2] was successfully ion monitoring at GEO orbit. bjective of the ESA Alphasat Program f the Alphabus platform for communication sat is based on Alphabus, the large European telecom r a joint contract with ESA and France’s CNES space y designed to expand Inmarsat’s existing global mobile ilt by Airbus DS through a public-private partnership (PPP) 2 (b) Geant4 transversal view of the MFS stack detector. Figure 1 m of thickness, with areas from 50 mm µ (a) MFS radiation monitor. 1 MeV, collimator disks with different appertures are place ∼ MFS is an instrument tailored and targeted to be a light ( Future telecom missions will encounter a severe radiation e Alphasat is a large telecommunications satellite primaril 1 detectors each with 300 tegrated and general purpose radiation monitor. Figure 1a i detection principle is based on the measurement of the energ 2. MFS Technical Overview interleaved by layers of shieldingfrom material 0.6 mm (aluminum up and to t 2 mm. In order to handle high particles fluxes o 1. Introduction of the Earth’s trapped electronminiaturization radiation of belts low and power the and Sola increasingly high sensitive speed to microelectroni radiation effects. The primary o agency. platform developed by Airbus DS and Thales Alenia Space unde telecommunication network, launched in July 2013. Itbetween was the bu European Space Agency (ESA) and Inmarsat. Alpha to facilitate an early first flight, andsatellites, in-orbit currently validation under o development with European ind launched on the 25th July 2013 from Kourou in French Guyana an orbit. In addition to thePayloads operational (TDPs) payload, aboard ESA the alsoEnvironment Alphasat prov and Effects spacecraft. Facility (AEEF) One [4],nology which of include Test thes Bed (CTTB) andled by a EFACEC Multi-Functional (Portugal). Spectrometer Theseveral objective technology of experiments the in TDP8 conjunction is with to radiat stud stack is surrounded by an aluminium shield to veto side parti ergies PoS(ICRC2015)137 L. Arruda ith the input performed ng Geant4 [6], [7] version alysis receives CTTB data p to 100 MeV. Electrons and Institute (PSI) in Switzerland n is under their responsability. adiation conditions at the Pro- houses the MFS stack detector stalled in Maia, Portugal. MFS ROM) and health housekeeping iables. A set of ROOT macros and energy recognition process, 3 ing and scientific data which are BERT_HP with improved neutron nd MFS is expected to be acquiring f the MFS geometry including the lectrons from 450 keV up to 7 MeV, stograms. The deposited energy in with the regulated secondary power to the result of detector’s calibration includes particle counters, electron, d calibration of the equipment under l of 4-5 fC and the front-end integra- or chamber with a radioactive source . The output of the Geant4 simulation Earth enabled to take this hazard into ousekeeping data includes temperature, s, both configurable. For the back-end grams. Level 2 data for MFS is created nd materials that compose it. The Shield- er than 20%, while for protons this value response was simulated and added at the µ 96.0 mm g in different database tables. The satellite × 10 ∼ 97.0 3 × s with a discharge curve of µ 2.125 ∼ . An external aluminium box of 242.5 ◦ Sr to provide a monoenergetic electron beam at Paul Scherrer MFS front-end electronics is based in an ASIC from IDEAS [5] w MFS was constructed by EFACEC, SA, Portugal and its operatio A detailed Monte Carlo simulation of MFS was implemented usi The MFS ProtoFlight Model (PFM) was tested under different r 90 is of 35 and the corresponding readout electronics. through a charge sensitive amplifier.tion Its time noise is is at the leve electronics MFS uses a FPGA with memories running: particle communications (TM/TC), drivers for memories (SRAMprocesses and (analogue EEP multiplexer plus an ADC).supplies MFS of operates the CTTB. The apparatus wasprotons designed from to measure 1 MeV e up toalpha 200 MeV particles and are alpha required particles to from haveis 5 energy MeV 10%. resolution u The bett mission lifetime of AEEF/TDP8scientific is data at during least the 3 years whole a period. MFS operations are made throughgenerates TDP8 Control two Centre different (OPS) raw in transmitted data to packs ground of via Leveland CTTB. 1: is responsible On housekeep for OPS, interpreting, separating TDP8 and In storin Flight Data An attitude and orbital data is made available from Immarsat. H voltage and power current consumptions.proton, The alpha scientific particles, data heavy ionby and processing other the particle Observational Data histo Files from Level 1. 3. MFS Geant4 simulation 4.9.4.p02 with the description of the detector’s geometry a ing physics list was used, which is based on former list FTFP_ cross sections. Figure 1bstack shows detector, the the Geant4 collimators and implementation theis o outer a aluminium ROOT box filewas with built a to tree perform of theeach analysis events detector and was storing converted to in all ADC produce the channel the(see output relevant next output according section). var hi Calibration and front-end electronics ton Irradiation Facility (PIF) [8]of and with the monochromat in 2010. The objective of theradiation. PSI tests The was ability the to verification an simulate in-orbit environment on analysis level. 4. Ground test data analysis PoS(ICRC2015)137 L. Arruda itor reproducing the experimen- m with a radius of 4 mm, without M. Beam particles were simulated gn producing several ground data line) compared with measured data assumed. Figure 2 shows the com- he Geant4 toolkit for Monte Carlo, is energy straggling from the initial rgy of 31.2 MeV. Simulation results e first silicon plane area in order to ation according to the manufacturer e simulated with the corresponding h MFS PFM simulation for the test .2, 134.84 and 150 MeV. A Gaussian multi-layer insulator was covering the of the spectral, spatial and angular dis- 4 Figure 2: Proton beam with 31.2 MeV - Simulation results (red (black line) for different silicon planes. sets that were used to validateusing the Geant4 the model G4GeneralParticleSource for (GPS) the which MFShigh PF is energy a particle part transport of andtribution t allows the of specification the primarybeam source energies particles. of 9.6, Proton 18.95,dispersion 31.2, beams in 61.9, wer energy 76.1, was 91, assumed 106.2, sinceproton 120 beam it of is 74.3 MeV known and that 150 there MeV.angular A flat, dispersion circular and proton bea placed 10tal cm position far was from simulated. the toprecreate The of the beam the particle area mon trigger is with equivalentapparatus to the during th first the tracker tests plane. andspecifications. so A it The was measured included pedestals in inparison the the between simul campaign data were measurements andbeam conditions results for obtained the wit first fourare planes in for very a good proton agreement beam with ene the test beam data. consideration in the design stage and to approve the PFM desi PoS(ICRC2015)137 ) E ( q (6.1) , i RF L. Arruda equation of while 17, given by the ] , 1 1 − s = 1 i − , i C . MeV 2  FS Up Table (LUT), which was − ates, dE hapes and it was initially devel- ulated protons, electrons, alpha ) cm flux the deconvolution technique gether with the energy left in the [ E d already established but the RFs ion. MFS samples the spectra in s extracted have been successfully f rument response functions and the ntification procedure. The energy ( fferent proton and electron energy q tic trapped particles in the radiation , ent thicknesses above the first MFS eant4 MFS model. The background i ight electronics at the time of the SEP dent proton and electron fluxes. Here, opped by the tantalum collimator. An tiple patterns of deposited nergy in the ively the unfolding of measurements - he detector with maximum energy and . The calculation of proton and electron energies by each species in ADC chan- RF more critical for protons and alphas than e ) , E p ( q f = q ∞ 0 Z 5  e , p ∑ = q = q , i C for each MFS channel has been derived by the simulations of e , ) p ∑ E = ( q q , i = i RF C requires the solution of Eq. 6.1 which is a Fredholm integral ) E ( q f denotes the differential omni-directional fluxes in units o ) For the efficient conversion of MFS measurements to particle This method does not require any assumption on the spectral s The measurements of MFS unit are provided in terms of count-r The MFS particle identification algorithm is based in a Look- The response matrix E ( q f describes the corresponding response functions for the first kind. presented in [10] was applied.using The a technique singular applies value iterat decompositionranges. (SVD) approach over di oped for the unfolding of ESA/SREMused measurements. for The the result estimation ofbelts solar [11]. proton fluxes [10] and energe differential fluxes Each term in the sum is attributed to measurements of the inci sum: omni-directional fluxes of electrons andin protons each using channel the was G broad also in evaluated overlapping using energy Monte bands as Carlomain can reason simulat be is seen due from tosilicon the sensor the inst which effect is not of segmented. thedifferent This collimator sensors fact for leads with to the differ mul same initial kinetic energy and is improved definition of the MFSused energy in the channels analysis is correspond to foreseen thoseevents an implemented studied. in the fl 6.2 Unfolding MFS data for electrons. In fact electrons with less than 5.8 MeV are st built based on the analysisparticles of and heavier Monte nuclei. Carlo The MFSnels thresholds response are for to stored deposited in sim the LUTdetector and before the the maximum energy one depositedreconstruction with to is maximum possible allows based the onon particle the the ide information deposited about energy t in the previous detector. 6. MFS flux spectra reconstruction method 6.1 Derivation of MFS response functions 5. Particle Identification and Energy reconstruction with M PoS(ICRC2015)137 L. Arruda ally spaced bins within oton dominated environment series based on Alphasat/MFS or the determination of the numerical oton flux results for proton energies 20 logarithmically spaced bins within measurements of MFS unit during the 6 46 MeV derived using Alphasat/MFS data (black 137 MeV derived using Alphasat/MFS data (black = = E E 150 MeV and the electron response functions in 7 logarithmic 8 MeV in order to apply the SVD unfolding method [10]. − − 4 1 In the current section, characteristic results based on the The derived results show that the unfolding of MFS data in a pr = = p p crosses) and INTEGRAL/SREM (red crosses) measurements. Figure 4: Differential proton flux series at Figure 3: Differential proton flux series at 6.3 Results moderate solar proton event of Januarysolution 2014 of are 6.1 presented. the F proton responseE functions were binned in using the SVD approachabove provides 40 consistent MeV. differential pr Figures 3 and 4 present differential proton flux E crosses) and INTEGRAL/SREM (red crosses) measurements. PoS(ICRC2015)137 L. Arruda S proton response functions. asat/MFS P5 and P9 channels blue crosses) proton fluxes with blue crosses) proton fluxes with ck line) compared to virtual data ck line) compared to virtual data d by folding the derived differential oton flux series at energies above 40 d agreement - within an order of two. ons, and the different characteristics of the 46 and 137 MeV. It can be seen that despite the 7 = E Figure 6: Time series of Alphasat/MFS/P5 measurements (bla and compare them with MFS reconstructed count-rates derive reconstructed by folding INTEGRAL/SREM (red line)P9 and proton MFS response ( function. proton flux series of Alphasat/MFS and INTEGRAL/SREM with MF Figure 5: Time series of Alphasat/MFS/P5 measurements (bla reconstructed by folding INTEGRAL/SREM (red line)P5 and proton MFS response ( function. and INTEGRAL/SREM measurements for different orbital characteristics of theconsidered considered radiation missi monitors, the derivedThe fluxes are same in conclusions goo are reachedMeV. for In all addition, the differential figures pr 5 and 6 present measurements of Alph PoS(ICRC2015)137 L. Arruda ation Environment edia/document , Proceedings of the , Nucl. Instrum. p ut. asurements in P1-P4 chan- 14.2304982, (2014) attributed to the proton response ijk, The Netherlands, 13th and 14th he measurements and the derived eV are not consistent with INTE- f , oral comunication at Space Radiation on of statistical significance at ener- , IEEE Transactions on Nuclear Science , E1 reference ASA-ESA-SP-TDP8-010, he INTEGRAL/SREM proton fluxes. Republic, Sept. 27-Oct. 1, 2010, , IEEE Transactions on Nuclear Science Vol BERM & , Nucl. Instrum. Methods A 372 (1996) 469. 8 llite-missions/a/alphasat , Nucl. Instrum. Methods A 506, 3 (2003) 250. , ESA, May 5, 2011, URL: http://telecom.esa.int/telecom/m Unfolding and Validation of SREM Fluxes Development and Validation of the Electron Slot Region Radi The proton irradiation facility at the Paul Scherrer Instit , , Alphabus, a successful European Public Private Partnershi Geant4 developments and applications SVD Approach to Data Unfolding , , , , et al. Efacec Space Radiation Monitors MFS et al. et al. et al. et al. et al. et al. , IEEE Transactions on Nuclear Science, DOI10.1109/TNS.20 ¨ oker, A. /Alphabus%20factsheet%2010-5-2011%20JH%20%281%29.pd 61st International Astronautical Congress, Prague, Czech IAC-10.B2.1.7 and plasma Environment Monitoring Workshop, ESTEC,May Noordw 2014 no. 3, 2009 Alphabus Fact Sheet 53, 1, pp: 270-278, 2, FEB 2006 Methods Phys. Res. B 113, 54 59, 1105 (2012). Model An evaluation of the performed comparisons shows that MFS me [2] [4] Alphasat TDP8 AEEF technical specification phases B, C, D [3] https://directory.eoportal.org/web/eoportal/sate [1] Cussac, T. [6] Agostinelli, S; [7] Allison, J; [5] Marques, A., [8] Hadjas, W. [9] Sandberg, I. The comparisons performed for the MFS P-channels show that t response functions for P5-P9 channels are consistent with t nels and the derived protonGRAL/SREM flux measurements. series The for observed energies inconsistency can belowfunctions be 40 of M MFS channels whichgies provide above coherent 40 informati MeV. References [10] H [11] Sandberg, I.