5th Jan 2017 KMI2017 Poster 34

Osamu Sato , T. Naka, M. Yoshimoto, S. Tada (Nagoya University)
A. Ariga, T. Ariga, M. Vladymyrov (BERN University)
Motivation on the study
Fine grain Emulsion NIT (Nano Imaging Tracker)

Sample for the study

 Mono Pole, Z=137 like , search by Emulsion Cloud Chamber.
 We have not satisfied with OPERA type films for high-z (z>26) particle’s
charge determination by following reasons.
A) Poor charge determination powerB) Huge number of δ rays are recorded and tracking by usual automatic
track selector developed for MIP dose not work.

 Standard nuclear emulsion ,OPERA type emulsion, is made with
200 nm AgBr crystal .
 NIT was developed at Nagoya University F-lab for Dark matter
detection. The AgBr Crystal size is 40 nm to detect short as 100
nm recoiled nucleus by Wimp Dark Matter.
 NIT have less sensitivity than OPERA type emulsion. Energy
deposition with several 10th x MIP can be recorded as track.

 Breakup product track slopes are very close each others !
Two body breakup by 50:50 ( ie. Two A=207/2 ) breakup case ,angle 15.3mrad/A .  around 0.15mrad.
To separate two particles, Z distance between interaction point toNIT is needed.
Assuming 5um is enough to separate tracks,
0.15mrad * dZ > 5um dZ > 33333 um = 3.3 cm
dZ = 4cm space was used for test beam.

 NIT have less sensitivity than OPERA type emulsion,
blind for energy deposition less than several 10th x MIP.
 So no delta ray tracks is recoded in NIT, just track core will berecorded We will make charge determination by emulsion sensitivity control.

Pb ion beam exposure at CERN H4 Pb (z=82) beam exposure at CERN at 2016 Nov. and Dec.
A) Tracking of Pb track itselfB) Pb breakup tracks with target nucleus , C in plastic.

Spot size of the beam

ECC made by NIT and OPERA were exposed.
18th Nov and 8th Dec 2016.

10cm☆ Horizontal exposure☆ Vertical exposure

PbPb

12cm

Target xy axis moverfor uniform exposure

yPb

PbPbx

Pb ion track recorded in OPERA type film
Horizontal samples (no sensitized)

Vertical samples (AuS)a) and b) are different focus depth image of the same view, different charges are seen in the view.

a)b)

Epi-illumination
same view with c)d)c)

Pb ion track recorded in NIT (HA) film
Horizontal sample Epi-illuminationA) and B) are different focus depth image of the same view, different charges are seen in the view.

A)

B)

C)

D)

130μm
Summary

Pb ion Vertical track scanningby automatic scanning system
12cm×10cm full are of NIT film were scanned as a trial.
5-6min per one surface by HTS.  1000m2 scanning is no problem.

Pb tracks scanned by HTS
Top:Tracks in beam angle
Bottom : Tracks in side band angle
Left : Pulse height
Right : Pulse height volume
Pb ion tracks are recognized by HTS
Consistent track density with exposed density

Fine grain emulsion, NIT have nice feature to detect
high-Z particles.
It could be used as ECC with standard nuclear
emulsion for high-Z particles charge determination
at Mono Pole Search.
A test exposure of ECC made by NIT, OPERA typefilms was done in 2016 autumn.
As the preliminary results.
a) Pb(Z=82) ion tracks can be scanned by automatictrack selector.
b) It looks charge of the interacted Pb remnants canbe distinguished.
In future, a large scale Mono Pole search can bedone by ECC detector surface of 100m×10m.