1. The Particle Detectors (The Image Detectors)
Doç. Dr. Erhan Pesen
VIII. Uluslararası Katılımlı Parçacık Hızlandırıcıları ve Detektörleri Yaz Okulu
Bodrum

2. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
History
Early detectors are Image Detectors. Principle: What you see what you get.
Could Chambers
Bubble Chambers
Nuclear Emulsions
Doç. Dr. Erhan Pesen Bodrum

3. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
The Cloud Chambers ( )
The images at left are typical of those obtained by Wilson (C. T. R. Wilson, Proc. Roy. Soc. (London), 87, 292 (1912)).
Also called Wilson chamber
The cloud chamber contains a supersaturated vapour of water or alcohol.
A charged particle interacting with the mixture, creates ions.
The ions act as condensation nuclei around which a mist (cloud of particles) will form
High energy alpha and beta particles leave a track due to the ions they produce along their path
If a magnetic field is applied positively and negatively charged particles will curve in opposite directions
Doç. Dr. Erhan Pesen Bodrum

4. The Discovery of Positron
Positron discovery, Carl Anderson 1933 [Nobel price 1936]
Magnetic field Gauss, chamber diameter 15cm.
A 63 MeV positron passes through a 6mm lead leaving the plate with energy 23MeV.
The ionization of this particle, and its behavior in passing through the foil was the same as those of an electron but with positive charge
Doç. Dr. Erhan Pesen Bodrum

5. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
The Discovery of Muon
Muons were discovered by Carl D. Anderson and Seth Neddermeyer at Caltech in 1936 with a cloud chamber while studying cosmic radiation
Doç. Dr. Erhan Pesen Bodrum

6. The Bubble Chambers (1952-1985)
Invented in 1952 by Glaser (1960 Nobel Prize in Physics)
A bubble chamber is a vessel filled with a superheated transparent liquid (Hydrogen at T=30K). A charge particle initiate boiling.
Urban history: Glaser was inspired by the bubbles in a glass of beer
The size of the chambers grew quickly:
– 1954: 6.4cm
– 1954: 10cm
– 1956: 25cm
– 1959: 183cm
– 1963: 203cm
– 1973: 370cm
Some disadvantages:
– It cannot be triggered
– Low rate capability
– The photographic readout: for data analysis one had to look through millions of photos
Doç. Dr. Erhan Pesen Bodrum

7. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
The Discovery of Omega
Doç. Dr. Erhan Pesen Bodrum

8. The Discovery of Neutral Currents
Gargamelle, a very large heavy-liquid (freon) chamber constructed at Ecole Polytechnique in Paris, came to CERN in 1970.
2 m in diameter, 4 m long and filled with Freon at 20 atm, in 2 T B field
Gargamelle in 1973 was the tool that permitted the discovery of neutral currents.
Doç. Dr. Erhan Pesen Bodrum

9. Nuclear Emulsions (1937 - ---)
Nuclear Emulsion particle detectors feature the highest position and angular resolution in the measurement of tracks of ionizing particles.
Nuclear Emulsion, used to record the tracks of charged particles, is a photographic plate.
A photographic emulsion consists of a large number of small crystals of silver halide, mostly bromide.
The sensitivity to light has allowed silver halides to become the basis of modern photographic materials.
A silver halide is one of the compounds formed between silver and one of the halogens — silver bromide (AgBr), chloride (AgCl), iodide (AgI), and three forms of silver fluorides
The method of recording tracks of charged particles in photographic plates is based upon two achievements of modern technology, the photographic emulsion and the optical microscopes
Doç. Dr. Erhan Pesen Bodrum

10. Nuclear Emulsions (1937 - ---)
A nuclear emulsion plate is a photographic plate with a thick emulsion layer and uniform grain size.
– It records the tracks of charged particles passing through
– It produce a cumulative record
– The plates must be developed before the tracks can be observed.
In 1937, Marietta Blau and Hertha Wambacher discovered nuclear disintegration stars due to spallation in nuclear emulsions exposed to cosmic radiation at a height of 2,300 meters above sea level
Doç. Dr. Erhan Pesen Bodrum

11. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
The Discovery of Pions
The pion was discovered in Nuclear emulsion techniques, Powell 1947; Nobel Prize 1950
Discovered in 1947 in nuclear emulsions exposed to cosmic rays, and they showed that it decay to a muon and an unseen partner.
The constant range of the decay muon from the pion decay indicate that this is a two body decay
Doç. Dr. Erhan Pesen Bodrum

12. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
The Discovery of Kaons
First evidence of the decay of the Kaon into 3 Pions was found in 1949 in Nuclear emulsion (by G. Rochester at Manchester)
Doç. Dr. Erhan Pesen Bodrum

13. Particle discoveries by 1959Ω-
Doç. Dr. Erhan Pesen Bodrum

14. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
Discoveries Timeline
Today > 200 particles listed in PDG:
27 have cτ > 1 μm
• they can be seen as tracks in a detectors
• 13 have cτ < 500 μm
• displaced vertices
Doç. Dr. Erhan Pesen Bodrum

15. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
Nuclear Emulsion
The only one that survives in Early Image Detectors
No time resolution
No vertex location information
Very good spatial resolution
Very good track, two track resolution (grain size ~1μm)
Events are recorded and stays forever
Doç. Dr. Erhan Pesen Bodrum

16. Neutrino Oscillations
Doç. Dr. Erhan Pesen Bodrum

17. Recent Application : CHORUS (1992-2002)
Calorimeter
Air-core magnet
Spectrometer n
Emulsion target
4 stacks each made of 36 plates
Plastic base: 90 μm
Emulsion on both side: 350 μm
Total mass : 770 kg
Active target
Doç. Dr. Erhan Pesen Bodrum

18. The Emulsion Development
Photographic developer is a chemical amplifier acting on the latent image.
A rather complex physics-chemical process is able to transform those grains with a suitable development centre into metallic silver.
After development, a silver halide emulsion is placed in a second bath, called as fixer which dissolves the unaffected grains of silver halide but leaves the small black granules of silver.
Finally, The plate is washed and dried.
Emulsion Films drying after development
Doç. Dr. Erhan Pesen Bodrum

19. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
Automatic Scanning
Tracks reconstructed by a hardware video processor
frame to frame emulsion grains coincidence
CCD
camera
150x150 mm view
microscope
stroke
CCD
camera
track
X50 magnification
~3mm focal depth
tomographic image
350 mm (175 mm)
emulsion sheet
90 mm plastic backing
emulsion plate
350 mm (175 mm)
emulsion sheet
Doç. Dr. Erhan Pesen Bodrum

20. CERN/NIKHEF Scanning Systems (year 2000)
Doç. Dr. Erhan Pesen Bodrum

21. Scanning System In Nagoya ( year 2000)
Network data storage
UTS = a machine for general scanning: ~1 cm2/hour
Doç. Dr. Erhan Pesen Bodrum

22. Tracking and Reconstruction
Reconstruct full vertex topology
At least 2-segment connected tracks
Track segments from 8 plates overlapped
Eliminate passing-through tracks
‘Emulsion is the mass storage’
~7000TB
(Prof.K.Niwa)
Doç. Dr. Erhan Pesen Bodrum

23. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
Charm Dimuon Event +
Zoom D+ h -
Doç. Dr. Erhan Pesen Bodrum

24. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
Detection of Ds
Doç. Dr. Erhan Pesen Bodrum

25. Today’s Application :The OPERA Experiment
Mainly designed for the direct search of ντ appearance in the pure νµ CNGS beam from CERN to Gran Sasso(732km).
Based on the use of Emulsion Cloud Chambers (ECCs) and of electronic detectors(Hybrid Detector).
In an ECC the nuclear emulsion films act as very high precision tracking detectors, and are interleaved with plates of lead.
The brick, is made of 57 emulsion films interleaved with 56 lead foils of 1 mm thickness. It has 128x102x79mm3, and weighs 8.3 kg.
Emulsion Cloud Chamber
Doç. Dr. Erhan Pesen Bodrum

26. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
OPERA Setup
The distinctive feature of ντ charged-current interactions is the production of a short-lived τ lepton (cτ =87 µm).
This is achieved in OPERA using the Nuclear Emulsion technique that features an unrivaled spatial resolution (≤ 1 µm).
OPERA Detector is a hybrid (emulsion+electronics) with a modular structure. 2 SuperModules=2*(31walls+1spectrometer) Total Mass: 1766 Tons. # of Bricks=206336
ECC measures: Kink of Tau, Momentum(via MCS), Electromagnetic Shower, dE/dX, e/π separation, Event Kinematics,Vertex Location, τ ID,
Magnetic Spectrometer: μ ID, charge and momentum.Target tracker: Trigger and localiza ν interactions.
Doç. Dr. Erhan Pesen Bodrum

27. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
The required area of emulsion is of order of 100,000 m2 s
It is needed high-speed automatic scanning systems.
Scanning power is 10cm2/h at
LHEP
Emulsions are scanned at Europe and Japanese scanning Labs.
Doç. Dr. Erhan Pesen Bodrum

28. Emulsion Scanning LAB. At University Of BERN
Doç. Dr. Erhan Pesen Bodrum

29. The Tau-Neutrino Candidate
Doç. Dr. Erhan Pesen Bodrum

30. Proton Radiography With Nuclear Emulsions
To obtain medical images of the patient’s body (proton radiography).
Proton radiography allows obtaining images directly proportional to the average density of the traversed material.
Emulsion detector is cheaper and easier to install and remove.
Doç. Dr. Erhan Pesen Bodrum

31. Emulsion Hybrid Telescope For Cosmic Gamma-ray Observation
Telescope observes
Brightness (Magnitute)
Color (Wavelength)
Direction of the light
Emulsion Measures
Event Rate (Flux)
Energy (Momentum)
Direction of gamma-ray photon
2 mrad
Ultra Violet
(UIT)
Visible
(Palomar)
Reconstructed Tracks
Gamma Shower
Doç. Dr. Erhan Pesen Bodrum

32. Cosmic-ray Muon Radiography Of Volcanos With ECC
muons
ECC
Muon source with a well-known energy spectrum for different zenith angles.
A well-understood muon detector.
The information from counting muon events at different arriving angles can be used to infer on the matter profile.
Doç. Dr. Erhan Pesen Bodrum

33. Cosmic-ray Muon Radiography Of Volcanos With ECC
Doç. Dr. Erhan Pesen Bodrum

34. Doç. Dr. Erhan Pesen 14-09-2012 Bodrum
LEP Tunnel
Doç. Dr. Erhan Pesen Bodrum