S. AokiKobe University

OPERA Emulsion Workshop2006/12/09

Gamma-ray Telescope

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.

Balloon Exp @ Sanriku 2004/May/30

Micro Segment Chamber

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”.

SPring-8Laser Electron Photon Beam(by RCNP Osaka Univ.)

～70m

Angular Resolution

RMS x =

2.6 mradRMS y =

1.8 mrad

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

readout error

　 0.3m

　 0.2m

　 0.1m

GLAST

1 mrad

simulation

Thicker Base

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.

backup

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

Energy Measurement

E < “ 700 MeV ”(beam halo)

E > “ 700 MeV ”

E > “ 700 MeV ”

x　　　　　　　　　　　　　　　　　　

0.1 GeV

1 GeV

10 GeV

Angular Resolution (simulation)

68% 95%

68%　　　　　　　　　　　　 95%

68%

readout error　 0.3 m

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

Balloon Flight @ Sanriku 2004/May/30

88.6m

MSC (40cm50cm8X0)

“hinge” for shifter

flight path

503km

the

nort

h la

titud

e

the east longitude

• T=ｔ 0　　　　　　　　　　　　 T=t １　　　　　　　　　　　　 T=t2

“shifter” to get time information

MSC

MSC

Air-Bag

hinge

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

measured track density vs. displacement

projection

track displacement across the air-bag

measured vs. expected

@0km before launch

@14km @36km