Post on 21-Dec-2015
Photon Observation (pointing)
Radio
IR
Visible refrectable optical imaging
UV
X-ray
“MeV-γ” Compton scattering multi-Compton scattering
“GeV-γ” pair creation initial e-track measurement
“TeV-γ” air shower erenkov light imagingČ
The best tracking detector becomes the best “GeV-γ” telescope.
2 mrad
Current Situation in various wavelength range
ex. Crab nebula (M1)
Radio (VLA)
Infra Red (2MASS)
Visible (Palomar)
Ultra Violet (UIT)
X-ray (Chandra)
“TeV” Gamma (HESS)
“GeV” Gamma (EGRET)
30 mrad100 mrad
a lot of room to improve for “GeV-γ”
ConverterEmulsionmetal foil
spacer
Energy Measure( Em + Pb )
Fiber Tracker( X and Y )
γEmulsion hybrid Gamma-ray Telescope
Unit size is about 1 m2
according to EGRET, Crab = 43 ev / 6hour ・ m2 (E > 1GeV) Loaded on the Scientific Balloon ($0.1M/flight << satelite) Fiber Tracker for the “time stamp” Orientation monitor (gyro + “star camera”) should also be equipped, to know the direction w.r.t celestial sphere.
1.5mm1.5mm
10.5cm
6.5cm
hadron j et
electroron shower
g amma shower
Balloon Exp @ Sanriku2004/May/30
290µm(.002X 0)
deg1.0mrad2
μm3.0x
2mrad by single layer (290µm)
[rad]
“OPERA Film” tracker performance
In current method,angular resolution isdominated by “stage (z-axis) noise”.
290µm(.002X 0)
deg1.0mrad2
μm3.0x
“OPERA Film” tracker performance
2mrad by single layer (290µm)
μm100x
50mm
c.f. GLAST
410µm(.004X 0)
1 mrad
Intrinsic Tracking Resolution
Ag grain after development
dx
= 0.06mCompton Electron
Fog
M.I.P. Track
100m
M.I.P. Track
intrinsic tracking accuracy
• Original Crystal Size 0.2m
single grain resolution 0.2m/12 = 0.06m N grains resolution 0.06 /Nm
• Angular Resolution (200 m base)0.06/N * 2 / 200 = 0.4/N mrad
if N=9 0.4/N mrad = 0.13 mrad
Summary
We are developing Emulsion Hybrid Gamma-ray Telescope
Test with Laser Electron Photon Beam (Max. 2.4GeV)
Finding conversion point is OK
By current methods, RMS = 1.8~2.6 mrad (= 6~9 arc min)
and Outlook We shall improve angular resolution.
At first, 1 day flight at Sanriku Japan to detect Crab nebula.
If Solar flare happens during flight, we can see the point.
(Apparent diameter of the Sun = 0.5 = 9 mrad)
Next, Long Duration (1 week) Flight at south hemisphere
to see the Galaxy center and other objects.
Emulsion can measure …
brightness (magnitude) color (wavelength) direction
of the light.
event rate (flux) energy (momentum) direction
of the “GeV” photon.
Emulsion can be good Telescope.
Telescope observes …
plate- 1 25 26 35 36 50
Cu 50m Pb 500m
plate- 31 32 33 34 35 36 37 38 39 40 41
Cu 50m Pb 500m
Converter Energy Measure
Test Chamber
PM
MA
15mm t
Detection and Measurement of Gamma-ray
Net-scan reconstruction Manual Check
e-pair confirmation
Angle measurement
10 mrad
distribution in angular space 39 events form 5mm×5mm area
Signal to Background estimation
According to EGRET (ApJ.494, p734, 1998), Crub Flux = 2.0107 photons cm2 sec1 (@E >1.0GeV) During 24 hours flight, Crab is above the detector 6 hours with 45º aperture # of arriving photon is 43 photons with 1m2 area. # of Signal event will be 21 ev. with 50% X0 depth.
According to BETS, atmospheric gamma-ray flux is 63 photons m2 sec1 sr1 (@E >1.0GeV, 25g/cm2 height) 1.3103 photons cm2 sec1 sr1 (@E >1.0GeV, 5g/cm2 height) In the size of Crab nebula (11mrad2 = 4.0106 sr) 1.2109 photons cm2 sec1 During 24 hours flight, # of arriving photon is 1.1 photons with 1m2 area # of Backgound event will be 0.6 ev. with 50% X0 depth.
“TeV” Gamma Observation by HESS (Imaging Air Cerenkov Telescope)
PSF
1°×1 °
Crab nebula (M1)
Galactic Sources
“morphology”has become possible“TeV” Gamma region
dE/dx measurement
dE/dx (a.u.)
p ( = 0.79,
dE/dx = 1.23 MIP )
( = 0.99,
dE/dx = 1.08 MIP )
“OPERA film” KEK-PS 1.2 GeV/c beam (29 films)
momentum (p) measurementby multiple Coulomb scattering
MDM = 5.9 GeV/c with =0.21m
0 1 2 3 p (GeV/c)
p (GeV/c)
1.2 GeV/c
4 GeV/c
altit
ude
[km
]sh
ifter
di
spla
cem
ent
[0.1
mm
]
level flight at 36km
displacement by atmospheric pressure change
air bag #1
air bag #3
air bag #2 (slow change)
“boomerang” flightat 14km
Flight Altitude vs. Displacement
expected track density vs. displacement
@0km before launch
FLUX=10-2 cm2/sr/sec
T=6.5day=5.6x105 sec
W=0.5sr(<0.4rad)
2.8x103 /cm2
@14km
FLUX=2.1x10-1
T=4hour =1.4x104 sec
W=0.5
1.4x103 /cm2
@36km
FLUX=4x10-2
T=14hour=5.0x104 sec
W=0.5
1.0x103 /cm2
projection