Nuclear emulsion scanning
for double strangeness nuclei search
Junya Yoshida,
Kazuma Nakazawa, Khin Than Tint, Myint Kyaw Soe, Aye Moh Moh Theint,
Shinji Kinbara, Akihiro Mishina, Yoko Endo, Hiroki Ito, Hidetaka Kobayashi
Physics department, Gifu University, Japan
JSPS KAKENHI 23224006 and MEXT 15001001, 24105002
1
Ξ-
Double lambda hypernucleus
X-ray
ｎ
ｎ ｐ
ｐｎ
* Important subject to investigate hyperonhyperon interaction.
Vertex A
ｎｐ
ｎ
#1
Λ
ｎｐ
ｎｐ
* Tiny characteristic shape having 3 vertexes at
the rest point of X- hyperon in nuclear emulsion.
ｎ ｐ
ｐΛｎ
p + Ξ- → Λ + Λ + 28MeV
Vertex B
ｐ
Λ
π-
ｎ ｐ
ｐｎ
Vertex C
ｎ
ｐ
ｎ
ｐ
ｎ
PHYSICAL REVIEW C 88, 014003 (2013)
2
Nuclear emulsion plate: photographic tracking device for charged particles
charged particles
nuclear emulsion plate
layer structure
emulsion
base
emulsion
~450 micron
40 micron
~450 micron
AgBr crystals suspended in gelatin.
track
after photographic development
Read-out: by optical microscope
3
Emulsion pictures
4
Only 9 events are observed in 2000s in the world.
Various double lambda hypernuclei must be detected to investigate L-L interaction.
How we obtain more double lambda hypernuclear events?
* The experiment ten times larger than the previous experiment.
J-PARC E07 -> Ekawa-san’s talk
* PID for daughter nucleus -> Kinbara’s talk
Emulsion stack
K+ (p>1.0GeV/c)
Diamond target
KXDouble Lambda Hypernucleus
5
A schematic view of “Track following”
thin type plate, good angular resolution:
Interface between tracker and emulsion
stack.
thick type plate, large angular acceptance
For detection of nuclear events.
PoC. of automated tracking
system is ongoing
disassembled emulsion stack
Only 9 events are observed in 2000s in the world.
Various double lambda hypernuclei must be detected to investigate L-L interaction.
How we obtain more double lambda hypernuclear events?
* The experiment ten times larger than the previous experiment. (J-PARC E07)
* PID for daughter nucleus -> Kinbara’s talk
* New searching method: Overall-scanning method
Diamond target
Emulsion stack
K-
K+ (p>1.0GeV/c)
yield: ~30%
XKX-
K0
Double Lambda Hypernucleus
(K-, K0)
* Latent events (~10 times) may be recorded in existing emulsion.
7
Overall scanning
Concept and Key technologies;
(1). 3-dimensional scanning under optical microscopic view.
(2). Image process to find multi-vertex shape in emulsion.
* High speed is required
* The method is also useful to find calibration sources such as,
alpha decays, single lambda hypernuclei.
* This method will be applied to E07 after regular analysis with hybrid method.
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(2). Image process
J.Yoshida et al., JPS Conf. Proc. , (2014) 1.013070
Original image
Difference of Gaussian
Binalization
Gaussian filter
x20 Objective (NA0.35)
1 pix = ~0.6 micron
Filter for bold tracks
contour length > 5pix
area > 10pix
kernel size = 17pix
(smoothed – source)
if negative, brightness=0
Thinning
Prob. Hough Trans.
resolution = 1degree
threshold = 16 pix / line
threshold ~= peak*0.2
Vertexing
dist-edge-to-edge = 15pix
N_Tracks > 3
9
polygon area > 1000pix
A. raw image
B. blurred
brightness(x,y) = B - A
brightness(x)
brightness(x) = Blurred - Raw
Raw
Blurred
x
x
if negative, brightness = 0
10
(2). Image process
J.Yoshida et al., JPS Conf. Proc. , (2014) 1.013070
Original image
Difference of Gaussian
Binalization
dist-edge-to-edge = 8micron
Gaussian filterN_Tracks > 3
polygon area > 300micron2
x20 Objective (NA0.35)
1 pix = ~0.6 micron
Filter for bold tracks
contour length > 5pix
area > 10pix
kernel size = 17pix
tuned
Thinning
(smoothed – source)
~= peak*0.2
by Nagara
event
and somethreshold
alpha decays
if negative,
brightness=0
Prob. Hough Trans.
resolution = 1degree
threshold = 16 pix / line
Vertexing
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・extracted images of vertex-like-object
12
Eye check for extracted vertexes
example :E373 mod86 pl7
scanned volume: 2.2mm * 10mm * 0.9mm
detected candidates:
vertex:
361
3496
Alpha decay：
32
Beam Interaction:
SingleHyper:
329
6
misrecognition :
3135
Beam Int.
Alpha decay
crossing‐over of 2tracks:
<Ideas for improvement>
* Parameter tuning.
* Recognition under a higher magnificent optics after 1st level selection.
* And so on.
13
(1). A dedicated scanning system（Stage#7,8）
camera
collaborate with UNIOPT Co.
high resolution CMOS
2048*358 pixel
high frame rate
800fps
objective lens
Piezoelectric drive
wide F.O.V.
x20 dry lens (NA0.35)
1142*200 micron2
Piezoelectric drive
stroke
500 micron
period 5Hz
picture 40picts /cycle
emulsion plate
Continuously stage moving
Designed speed:
10mm*10mm*0.9mm / 2min. = ~40 hours @plate (340*335*0.9[mm3])
To accomplish scanning of ~1000 films within a few year.
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stage motion in X-Y plane (top view)
2
1
1.0 mm / sec
3
4
Yaxis
1.0 mm / sec
Xaxis
stage motion in Y-Z plane (cross sectional view)
40 picts.
Zaxis
Field Of View : 0.2*1.1 [mm2]
200msec /cycle
Yaxis
1.0 mm / sec
* Exhaustively scanning by a computer-controlled optical microscope.
* Continuous stage drive to save damping time of vibration.
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J.Yoshida
et al., JPS Conf.
Proc. , (2014)
* These are processed in real-time
by CPU&GPU
(5msec/pict.)
(2). Image process
1.013070
* Data is stored in HDDs
Difference of Gaussian
Original image
Binalization
Gaussian filter
x20 Objective (NA0.35)
1 pix = ~0.6 micron
Filter for bold tracks
contour length > 5pix
area > 10pix
kernel size = 17pix
(smoothed – source)
if negative, brightness=0
Thinning
Prob. Hough Trans.
resolution = 1degree
threshold = 16 pix / line
threshold ~= peak*0.2
Vertexing
dist-edge-to-edge = 15pix
N_Tracks > 3
16
polygon area > 1000pix
Quality checking for scanned data
Exhaustiveness of image taking
Trigger timing
Z
trigger
50views ->
trigger
trigger
Time or Y
Tiled binalized images.
200micron*1140micron*3views
The same layer ID
number_of_’1’_pixel
40pictures
surface
base
pict.ID
1
10
20
30
40
* Stage drive, piezoelectric, camera are synchronized. Trigger timing is proper.
* Missed trigger and troubles in data transfer < 3%
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Operation
Prototype
Upgraded
High-speed
Since
~2011
2014
Stage
Camera
100fps CCD
Z-drive
Stepping motor
Optics
Field of View 0.11*0.13mm2 0.18*0.21mm2
2013
Speed[mm3/h]
2.6
2700
Site
Gifu-univ.
Gifu-univ.
Toho-univ,Japan GNU,Korea
GNU,Korea
Scanned vol. ~5.0cc
13.1
just started
Found events;
~3000 alpha decays
~700 single hypernuclear event
7 three-vertexes candidates.
A typical twin-single-lambda- hypernuclear event (Kiso)
800fps CMOS
Piezoelectric
0.20*1.14mm2
Gifu-univ.
17.4cc
10 mm
18
summary
* Overall scanning
A new searching method for double lambda hypernucleus in
emulsion.
Concept: high speed 3D scanning & image recognition
* The current status
Scanning software, Image process is basically successful.
Improvement of detection efficiency and S/N ratio is being carried
out.
*Operation
In operation in Gifu-univ., Toho-univ., Japan, GNU, Korea.
~700 candidates of single hypernuclear
~7 3-vertexes candidates.
A typical twin-single-lambda- hypernuclear event (Kiso)
19
20
JPS Conf. Proc. , (2014) 1.013070
Image process
Difference of Gaussian
Raw image
Binalization
Gaussian filter
x20 Objective (NA0.35)
1 pix = ~0.6 micron
Filter for bold tracks
contour length > 5pix
area > 10pix
kernel size = 17pix
Thinning
threshold ~= peak*0.2
(smoothed – source)
if negative, brightness=0
Prob. Hough Trans.
Vertexing
resolution = 1degree
dist-edge-to-edge = 15pix
threshold = 16 pix / line N_Tracks > 3
polygon area > 1000pix
Synclonization between piezoelectricity and camera
400us 3.5V
(LVTTL)
Host PC
CMOS Camera
CameraLink Base & Full
Piezo Ctrl.
TRG
400us 5.0V
GPGPU
Main Board
BNC
PCI & PCI-E
Grabber Board
PiezoElec.
USB
Stage Ctrl.
command
USB
optics
TRG:
start sequential shooting
Z
Emulsion
thickness
vibration of focal plane driven by Piezoelectricity
Time or StageYaxis
22
Stage control
Z-Axis (Optics)
Host PC
Motor Driver
(3-axes)
X,Y-Axis (Stage)
Stage Ctrl.
Main Board
GPGPU
PCI & PCI-E
Grabber Board
LED Driver
command
LED Light
Serial
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Data transmission
Host PC
CMOS Camera
RAM
Grabber Board
PCI & PCI-E
GPGPU (GTX680)
CPU
Corei7
3960X
External HDD
Chipset
Stage Ctrl.
(1)
(2)
(3)
(4)
(5)
(6)
(7)
X79
eSATA (100MB/s)
シリアル
Camera -> grabber_board -> RAM
RAM -> GPGPU
Difference_of_Gaussians on GPGPU
GPGPU -> RAM
Binalization on CPU
RAM -> External HDD
Image process on another computer
2048*358 pix
8bit-depth
2048*358 pix
1bit-depth
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Overall scanning
ほかにも、乾板中にランダムに存在するキャリブレーションソース
アルファ崩壊、シングルハイパーも探索したい。
そこで
・原子核乾板の全体積を光学顕微鏡で走査し、
(1)高速顕微鏡画像取得の開発
・少なくとも1つの分岐点をもつパターンを検出
(2) 画像解析の開発
Stage size:
35cm*35cm (Nikon. )
45cm*45cm (Uniopt. )
Field of View:
115micron*135micron(x50 objective lens)
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Overall Scanning と解析のストラテジー
Phase I : 技術開発 兼 E373乾板の再解析
先の実験（KEK E373）の乾板を用いて技術開発
E373乾板の全体積をスキャンし、
従来比10倍、70例のダブルΛハイパー核検出をねらう
Phase II : E07実験解析のアシスト
キャリブレーションソース：アルファ崩壊の探索高速化
Phase III : E07乾板の再解析
E07乾板の全体積をスキャンし、
プロポーザル比10倍、103例のダブルΛハイパー核検出をねらう
26