Transcript High Energy Measurements for Solar, Heliospheric, Magnetospheric, and Atmospheric Physics R. P. Lin J.

High Energy Measurements for Solar,
Heliospheric, Magnetospheric, and
Atmospheric Physics
R. P. Lin
J. Sample, A. Shih, S. Christe, S. Krucker, I. Hannah
Physics Department & Space Sciences Laboratory
University of California, Berkeley
& D. Smith (UCSC), R. Millan (Dartmouth)
Apollo 15 Subsatellite
FAST
(Fast Auroral SnapshoT)
• Science Package
Electric Field Instruments
Particle Instruments
Electronics
• Mission Operations
• Science Operations
Launched on 21 Aug 1996
Mission Presently Operating
RHESSI
(Ramaty High Energy Solar
Spectroscopic Imager)
• Project Management
• Spacecraft Bus
• Science Package
Imager
Spectrometer
Electronics
• Mission Operations
• Science Operations
• Ground Data Systems
Launched February 5, 2002
Mission presently operating
Cosmic Hot interstellar Plasma Spectrometer
(CHIPS)
THEMIS Integration and Test
• Currently ongoing at the UCB Space Sciences Laboratory
• 5 identical spacecraft & instrument suites
RHESSI TGFs: Lightcurves
Durations from 200 us to 3.5 ms; consistent with
BATSE, shorter than most TLEs.
RHESSI TGFs: Spectrum
Summed spectrum of 289 TGF
Spectra tend to be similar from
event to event, but slightly mor
variation than chance
Models are relativistic runaway
breakdown simulation by
J. Dwyer.
Unabsorbed bremsstrahlung
-1
must be steeper than E
around 1 MeV; spectrum seen
2
requires > 50 g/cm of
intervening air
(Dwyer & Smith 2005,
in press)
Jan 17 2004, 12:46:50.970
Longest and brightest RHESSI TGF
Northern Chad (Sahara). No storms
here, but plenty of storms in Janua
at the conjugate point.
If every TGF has a conjugate flash,
the first Sahara event we see shou
be faint, not bright! Unless.....
We got lucky and caught the e- beam
directly with the spacecraft!
Currently looking for conjugate storms &
sferics
Multiple Scintillators for Terrestrial,
Cosmic, Solar, and Magnetospheric
Events (MSTCSM)
John Sample and Albert Y. Shih
Science objectives of MSTCSM
• MSTCSM can provide improved and completely new observations of
events ranging from those of terrestrial or magnetospheric origins to
those of solar or cosmic origins
• MSTCSM observes 20 keV to 16 MeV photons and 600 keV to 6 MeV
electrons with excellent time resolution
• For terrestrial gamma-ray flashes (TGFs), MSTCSM is more sensitive
than RHESSI and can obtain better timing information and structure
• For microbursts in the magnetosphere, MSTCSM can determine the
spectrum of the relevant particles for the first time and improve the
pitch angle determination by SAMPEX
• For solar flares, MSTCSM has an order of magnitude better time
resolution than RHESSI and more effective area (~ 8 times more at Xray energies, and ~ 2–3 times more at gamma-ray energies)
• For cosmic sources such as gamma-ray bursts and magnetars,
MSTCSM can look for time structure better than other instruments
Instrument design for MSTCSM
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2 cm
Spacecraft in a sun-synchronous
polar low-Earth orbit
Fixed pointing towards the Earth and
the Sun, but minimal requirements on
20 cm
accuracy
Two lanthanum bromide (LaBr)
scintillators and four plastic
scintillators, each 1-cm thick
 LaBr
Two sizes of plastic scintillators for
dynamic range
2 cm
Orientation of scintillators is depicted
for two points of view
One set of scintillators is shadowed
from the Sun for deadtime and pileup
considerations
20 cm
To Sun
To Earth
40 cm
 plastic
To Sun
To Earth
Technical details for MSTCSM
• Analysis chain similar to RHESSI
• Each scintillator event recorded
separately with time and energy
• Fast and slow shaping channels
• Timing: < 0.05 microseconds
• At very high count rates, individual
events are not retained, but spectra
are produced from the fast channel
• Onboard generation of lightcurves
for automatic and/or manual
selection of data periods to keep
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Component
Mass
LaBr scintillators
4.25 kg x 2
Plastic scintillators
0.85 kg x 2
PMTs
0.2 kg x 6
IDPU and electronics
2 kg
Housing
3 kg
Total
16.4 kg
~ 3 GB of data produced per day
8 GB solid state recorder
4 Mbit/s downlink
~ 0.1 m2 of solar panels with
battery to provide ~ 10 W power
< 0.1 m3 total volume
Spectral Components
total model
broad
De-excitation lines -narrow
Neutron-capture2.2 MeV
511 keV- positron
annihilation
power law - electron
bremsstrahlung
Germanium Array in Low Earth Orbit (GALEO)
Solar Hard X-ray Focusing Optics
S. Christe, S. Krucker, B. Ramsay (MSFC)
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Flare/CME Coronal Acceleration Region
Micro-Nano Flares
Electron beams
Type III radio bursts.
Type I Bursts
Quiet Sun
Axions
Science - Quiet Sun/Nanoflares
Hannah et al, 2007
THEMIS
Optic - 1 m focal length
Some Pictures
Detectors : Pixelated Si