JAXA status report 2018 Masanobu Ozaki (ISAS/JAXA) Brief Summary

• Not used frequently for spacecraft or manned-structure designing by engineers • Used for detector design/calibration and astrophysical simulations by scientists • Payload design/calibration: Hitomi/XRISM, Suzaku, Arase, Cubesat, … • Detector development • Astrophysical simulations

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 2 Spacecraft or Manned-Structure Designing?

• Geant4-use looks not so active: • Spacecraft design matured enough for near-earth mission? • Lunar, Martian or Venus mission can be treated as an extension of geostationary orbit—they have no magnetosphere. • Next frontier: • Jovian or Saturn mission (but no active study yet) • Lunar manned-base? (related to post-ISS)

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 3 Payload design/calibration

• Several Geant4-utilized missions: on-orbit or terminated • Hitomi (a.k.a., ASTRO-H: X-ray observatory) terminated due to on-orbit accident http://www.isas.jaxa.jp/en/missions/spacecraft/past/hitomi.html • XRISM—successor of Hitomi—(X-Ray Imaging and Spectroscopy Mission) under development • Arase (a.k.a., ERG: geospace probe satellite) on orbit http://www.isas.jaxa.jp/en/missions/spacecraft/current/erg.html • Suzaku terminated due to big solar flare in 2015 http://www.isas.jaxa.jp/en/missions/spacecraft/others/suzaku.html • Geant4 usage? • Detector’s shielding design  already reported in previous workshops • Precise detector calibration • Hitomi/XRISM  will be presented 3rd day • Arase • Suzaku

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 4 By courtesy of T.Mitani (ISAS/JAXA) High energy electron sensor onboard Arase High-energy Electron exPeriments(HEP) instrument on board Arase observes 70 keV– 2 MeV. The HEP consists of three HEP-L modules (70 keV – 1MeV) and three HEP-H modules (700 keV - 2MeV). A module consists of a mechanical collimator and stacked silicon strp detectors (SSDs). The Opening angle of the collimator: ~ 60 degree x 10 degree. To determine elevation angle, SSD has one dimensional position resolution.

Input particles 60 ° 3D view Plain view 10 °

Collimator θ

Al sheet

Stacked Silicon strip Detector HEP-L: Al sheet(12.5 µm) + 4 layers of SSDs SSD HEP-H: Al sheet(300 µm) + 8 layers of SSDs

5 6 sum_firstDetHit sum_firstDetHit Entries 904575 18000 Mean 771.8 (ISAS/JAXA) RMS 358.9 16000 T.Mitani

14000 ]

12000 keV

10000H - By courtesy of of courtesy By . 8000 HEP

6000 4 toolkit 4 * Observed count Observed * 1

4000 - Observed energy [ energy Observed

2000 700keV Geant

0 200 400 600 800 1000 1200 1400 1600 1800 2000 we use use we monoenergetic electrons with various energies energies various with electrons monoenergetic sum_firstDetHit ´103 sum_firstDetHit

Entries 980030 from distribution energy response incident a deduce calculate To we histogram, observed R. matrix R = flux Incident Mean 278.2 300 RMS 113.3 ] 250 keV

200 L - 700keV 150 R HEP

100 Observed energy [ energy Observed Observed energy Observed

Energy response of detectorof HEP Energy response 50 energy Incident

0

are irradiated to the HEP SSD module. SSD HEP the to irradiated are Figures below show detected spectra when spectra detected show below Figures To calculate detector response to electrons, electrons, to response detector calculate To 0 200 400 600 800 1000 1200 1400 JAXA status report 2018 (Masanobu Ozaki) By courtesy of T.Mitani (ISAS/JAXA) Response Matrix – Based on Geant-4 simulations, we have constructed response matrices for HEP-L and HEP-H. By inverting the the matrices, we derive incident electron differential fluxes from an observed count histogram. The resultant flux data are open to the public as Level-2 science data product. [Observed histogram] (1D) = [Response Matrix] (2D) x [Differential flux](1D)  [Differential flux] = [Response Matrix]-1 x [Observed histogram]

Electron count histograms over the incident-observed energy space simulated by the ERG-HEP simulator using Geant 4 toolkit

Park et. al, in prep.

7 Suzaku HXD detector precise calibration

Geant4 mass models Gamma-ray detection efficiency for each panel

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 8 Detector Development

• Geant4 is used to simulate the detector behavior • X-ray polarization detection with precise CMOS image sensor • Optimal scintillator design using G4 optical photon simulationBy courtesy of K.Asakura (Osaka-U) 12.4keV 24.8keV

4.25um 2.5mm 2.5mm

MF=16.6±1.2%@12.4keV MF=18.7±0.7%@24.8keV • Simulation of photoelectron tracks. • 100% polarized incident X-rays are irradiated. • Diffusion of the charge inside the detector is NOT taken into account.

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 9 Detector Development

• Geant4 is used to simulate the detector behavior • X-ray polarization detection with precise CMOS image sensor • Optimal scintillator design using G4 optical photon simulation for GRB detection fleet

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 10 By courtesy of M.Ohno (Hiroshima-U) fleet of cube-satellite w/ triangulation

Hurley+13

 dozen cube satellite constellation  localization by photon arrival  all-sky coverage time (no earth shadow) High timing synchronization by GPS huge effective area  <100 μ-sec timing accuracy results several arcmin localization accuracy (Pal+18 SPIE) CAMELOT (Cubesat Applied for MEasuring and Localising Transients) (Werner+18 SPIE) 2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 11 Detector designBy courtesy of M.Ohno (Hiroshima-U)

75 mm

Satellite platform : MPPC 3U Cubusat designed for “RADCUBE” 150 mm mission. Hungarian 3CS company + ESA 5 mm ! consortium

• two sides of lateral extension : CsI scintillator readout by ~268 cm2 x 9mmt is a basic idea to multi pixel photon counter (MPPC) maximize geometrical area is now being evaluated as the first • challenging for such “large and thin” feasibility study for their large light detector with small readout area yield, compact readout area and low power consumption. 2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 12 Detector feasibilityBy courtesy of M.Ohno (Hiroshima-U)

300

Energy (keV) Torigoe+ NIMA in press (Poster#**) 10 100 Single channel readout Coincidence sum )

Coincidence sum (scaled) deg angle ( angle

241Am 59.5 keV

incident zenith zenith incident GRB incident horizontal angle (deg)

✓ Developed a multi-readout system GRB ✓ for high light yield and redundancy Effective area simulation including ✓ AchievableComparable the observational low energy threshold capability to thesatellite one detector CAD model of Fermi-GBM ✓ 2 ~10keVwith our : enough single unit photon of Cubesat statistics ~350cm at 100keV w/o satellite from GRBs absorption 2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 13 By courtesy of K.Torigoe (Hiroshima-U)

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 14 Astrophysical Simulations

• Geant4 simulation in astrophysical scale (e.g., pc to Mpc) to represent observations • Hitomi results  will be presented 3rd day • Chandra spectrum of active galactic nuclei

M.Hikitani+ 2018 (doi: 10.3847/1538-4357/aae1fe)

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 15 Summary

• Geant4 not used frequently for spacecraft or manned-structure designing by engineers • Maybe some use PHITS • Used for detector design/calibration and astrophysical simulations by scientists • Payload design/calibration: Hitomi/XRISM, Suzaku, Arase, Cubesat • Detector development: Scintillator design, CMOS X-ray polarimeter • Astrophysical simulations: photon simulations observed by Chandra, Hitomi

2018-11-28 (G4SUWS2018) JAXA status report 2018 (Masanobu Ozaki) 16