The Konus-fg experiment for gamma-ray burst studies in gamma-400 M. V. Ulanov, R. L. Aptekar, D. D. Frederiks

The Konus-FG experiment for gamma-ray burst studies in GAMMA-400

• M.V. Ulanov, R.L. Aptekar, D.D. Frederiks,

• S.V. Golenetskii, E.P. Mazets, and V.D. Pal’shin

Historical remarks

• GRB research experiments:

• KONUS / Venera 11–14 (1979–1983)

• KONUS-WIND (1994–present time)

• CORONAS-I, CORONAS-F, CORONAS-PHOTON (2001–2009)

• Autonomous localization:

• GRANAT (1989)

• KONUS-A / Cosmos-2326, 2367, 2421 (1995–2008)

Joint Russian-American Konus-Wind experiment

Konus-Wind GRB Experiment

• Two detectors S1 and S2 (NaI(Tl) 13cm diameter, 7.5cm height, Be entrance window). Placed on opposite faces of the spacecraft, observing the south and north ecliptic hemispheres of the sky.

• Background mode: G1 (20–80 keV), G2 (80–300 keV), G3 (300–1200 keV) with time resolution 1.47–2.94 sec.

• Burst mode: time resolution 2ms–256ms, energy spectra (20keV–15MeV).

Scientific goals of the Konus-FG experiment

• Detection and prompt (1–2 sec) localization of GRB sources in 10 keV – 3 MeV energy range with accuracy of 0.5–3°.

• Localization information can be used for GAMMA-400 pointing to burst source or for further data analysis.

• Study of temporal and spectral properties in 10 keV – 15 MeV range with two high-sensitive spectrometers.

Schematic diagram of the Konus-FG instrument

Konus-FG-DN: localization units

• The localization subsystem is formed by four identical detectors “Konus-FG-DN”, registering photons in 10–700 keV range.

• The detector’s anisotropic angular sensitivity is proportional to the cosine of the angle of incidence and is formed in the soft part of spectrum ~40–160 keV.

• The axes of the DNs are offset from the symmetry axis by 30° and separated in azimuth by 90°.

• Field of view of each detector (2π sr) should not be occulted by construction details of the telescope.

• The system provides burst localization in upper hemisphere within detector’s field of view (~75% of 2π sr) that exceeds the effective angular aperture of the telescope.

Konus-FG-DS: spectrometry units

• The spectrometric subsystem includes two identical wide directional spectrometry detectors “Konus-FG-DS” operating in 10keV–15MeV energy range.

• The axis of the detectors should be pointed parallel to the main spacecraft axis that provides the survey of the whole celestial sphere 4π sr.

• DS detectors obtain detailed information about energy spectra and time history of bursts.

• Konus-FG-DS will be a valuable part of triangulation network (IPN), which will improve the reliability and accuracy of automatic localization.

Location of Konus-FG units (preliminary)

The Konus-FG-DS detector unit

The Konus-FG-DN detector unit

Konus-A / Cosmos 2326, 2367 Localization detector prototype

• Each detector had 130 mm in diameter and 30 mm in height with the passive shielding on lateral side.

• The axes of detectors are offset from symmetry axis by 30° and separated in azimuth by 90° .

• The accuracy of localization is of 0.5 to 2–3 angular degrees depending on the burst intensity.

Unsolved problems

• Arrangement the optimal location of Konus-FG detectors on the GAMMA-400 spacecraft.

Broadband observations of the naked-eye gamma-ray burst GRB080319B

The ultra-luminous GRB110918A

Konus-Wind and Helicon (CORONAS-F) simultaneous observations of giant flare from SGR1806-20 on December 27, 2004

Konus-Wind and Helicon (CORONAS-F) simultaneous observations of giant flare from SGR1806-20 on December 27, 2004