The Wide Field Monitor for ESTREMO/WFXRT: A Summary of the 2-3 August Thinkshop

1. The Wide Field Monitorfor ESTREMO/WFXRT: A Summary of the 2-3 August Thinkshop Marco Feroci IASF/INAF – Rome ESTREMO/WFXRT Workshop Rome 12-13 September 2006

2. (Very) Minimum (baseline) requirements for WFI(*) Requirements for the localizator are: • Flux: rather bright events (>1 Crab) • Energy range: need to go down to at least 4 keV. Upper range: not a driver for localization (but see below), 40 keV should be good enough. • FOV > 3-4 sr • Localization (driven by NFI): better than 3 arcmin • Need to have at least the temporal signature in the hard X-ray range (>100 keV) to identify a GRB (*) Presentation by L. Piro ESTREMO/WFXRT Workshop Rome 12-13 September 2006

3. Additional Requirements for WFI: Study of the prompt emission of GRBs See L. Amati ESTREMO/WFXRT Workshop Rome 12-13 September 2006

4. Gross Hardware Constraints(*) Mass: 150 kg, including cont.y Power: 120 W, including cont.y Volume: 70 cm height, Vega fairing (220 cm) symmetric Telemetry: few Mbit/s (X-band) (*) Presentation by L.Piro ESTREMO/WFXRT Workshop Rome 12-13 September 2006

5. Designs Proposed for WFM • ISGRI/BAT-like configuration, with optical design and detector technology to be assessed (+open field det.) • Improved SuperAGILE technology, plus “classical” open-field spectroscopy detector Both options satisfy the baseline scientific requirements. Option (a) offers better performance for the study of the prompt emission of GRBs and (Hard) X-ray transients, simultaneously over half sky: probably unprecedented. high quality ASM science Option (b) requires smaller budgets (factor of 2-3) but provides coarser spectral info on prompt emission. Soft X-rays (~1-5 keV) probably require SDD in both options. Fine determination of spectral parameters requires area or small FOV for the spectroscopy detector. ESTREMO/WFXRT Workshop Rome 12-13 September 2006

6. Option (a) (baseline) • 2D pixellated detector – pixel size 2-3 mm • Energy range: 1/10 – 200 keV, depending on technology • Detector options: CZT, CdTe, SDD+CsI • Geometric Area: 3700-5000 cm2, depending on solution • Eff. Area: 350 (flat) or 700-2500 cm2(min/max), dep. on solution • 2D Coded Mask • Mask-Detector distance: 400-700 cm, depending on solution • FOV: 3-6 sr, to be optimized • Angular Resolution: 30-40 arcmin • Point Source Location Accuracy: 2-3 arcmin • Sensitivity (1s): 0.5-5 Crab, to be optimized • Weight: 150 kg • Power: 120 W ESTREMO/WFXRT Workshop Rome 12-13 September 2006

7. Option (b) (back-up) • Detector: 1D microstrip – pixel size 120 m • Energy range: 3-5 – 50 keV, depending on ASIC technology • Detector options: Silicon,1-2 mm thick, single/double-sided • Geometric Area: 5000 cm2 • Eff. Area: 100/200 cm2 (any direction), dep. on solution • 1D/2D Coded Mask • Mask-Detector distance: 15 cm • FOV: 6 sr, to be optimized • Angular Resolution: 6 arcmin • Point Source Location Accuracy: 1-2 arcmin • Sensitivity (1s): 1 Crab, to be optimized • Weight: 30-50 kg • Power: 50 W ESTREMO/WFXRT Workshop Rome 12-13 September 2006

8. Summary of Solutions ESTREMO/WFXRT Workshop Rome 12-13 September 2006

9. Summary of Summaries • Arcmin Localization of bright bursts (say, 50 events/year) in 10-100 keV “easily” reachable • Good low energy (<5-7 keV) sensitivity requires R&D or dedicated detector • Good high energy (>200 keV) spectral sensitivity may require dedicated detector • Good spectral response on wide energy range (fine determination of spectral parameters) may require trade-off on the area/FOV. Different optimization wrt point (1) Need A Clear Assessment of Scientific Requirements ESTREMO/WFXRT Workshop Rome 12-13 September 2006