Particle Identification with
CHanneling radiation
(PICH)
M. Nicola Mazziotta
INFN - Bari
Commissione Scientifica Nazionale V
Riunione del 19-23 Settembre 2005 – NAPOLI
Composizione Gruppo
M. Brigida, C. Favuzzi, P. Fusco, F.
Gargano, N. Giglietto, F. Giordano,
F.Loparco, B.Marangelli, M.N.
Mazziotta, N. Mirizzi, M. Perchiazzi, S.
Raino’, A. Sacchetti and P. Spinelli
INFN Sezione di Bari
Dipartimento di Fisica Universita’ degli Studi di Bari
Comm. V - 19-23 Settembre 2005 - Napoli
2
R&D Scope
Scope:
Development of a detector for mass tagging at
high energies by means of channeling radiation
Application:
Particle identification in a high energy
unseparated collimated beam where
Cherenkov counters become unpractical and
TRDs cannot perform full electron/hadron
discrimination (p>100GeV/c)
Comm. V - 19-23 Settembre 2005 - Napoli
3
Interaction in crystals
When a parallel beam of electrons or positrons crosses a
crystalline target in directions far from major crystal axes or
planes, the well-known incoherent bremsstrahlung is emitted
As the direction of incidence is turned towards planar
directions, the projectiles start to feel the crystalline structure,
and coherence in the emitted radiation results in the peak
structure of coherent bremsstrahlung.
If the projectiles are incident nearly parallel to planar
directions, they become trapped in the potential wells due to
the planes, resulting in the strong steering effect called
channeling. This special motion also gives rise to coherence
effects, and the resulting radiation is called channeling
radiation.
Comm. V - 19-23 Settembre 2005 - Napoli
4
Channeling Radiation
The channeling radiation is emitted when
charged particles pass through a crystal along a
crystallographic direction:
ψ < ψcrit
ψ = particle incidence angle
ψcrit = critical channeling angle (Lindhard angle)
ψ crit
=
4Z 1Z 2 e 2
pvd
4Z 1Z 2 e 2NdpCa
pv
Axial
Planar
ΔE ∝ γ2 (energy loss)
ω ∝ γ3/2 (photon energy)
θ ∝ 1/γ (emission angle)
Comm. V - 19-23 Settembre 2005 - Napoli
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Main features of Channeling Radiation
Unlike the Bremsstrahlung, Cherenkov and Transition
Radiation, it strongly depends on the charge sign
Unlike the Cherenkov radiation, it depends not only on the
velocity but on the particle energy as well
Unlike the Bremsstrahlung, it has well pronounced
characteristic frequencies (peaks) depending on the
characteristics of particles and crystals
The position of characteristic frequencies is tuned by the
change of the direction of the crystal bombardment and (or)
the beam energy, and also the angle of observation
The radiation has a high degree of linear polarization for
planar channeling (≈ 80%)
In the hard X-ray and γ-ranges it exceeds other types of
radiation approximately by two orders in spectral intensity and
by three orders in luminosity
Comm. V - 19-23 Settembre 2005 - Napoli
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Channeling Radiation
(The Kumakhov effect)
The channeling effect was discovered in the early sixties
by anomalous energy loss in crystalline materials (G.R.
Piercy et al., Phy. Rev. Lett. 10 (1963) 399)
A classical theoretical treatment was given by J.
Lindhard Phy. Lett. 12 (1964) 126
The prediction of the channeling radiation was given by
M.A. Kumakhov Phy. Lett. 57 (1976) 17
First experimental confirmation in 1978 at SLAC by
Stanford-Kharkov-Yerevan collaboration (positrons 4-14
GeV in the 80 µm <110> diamond)
Comm. V - 19-23 Settembre 2005 - Napoli
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Channeling radiation spectra (N.
(N A.
Filatova et al., Phy. Rev. Let. 48 (1982) 488)
Photon energy spectra for <110> planar channeling radiation
from 10GeV/c positrons traversing a 95 µm thick silicon crystal.
Comm. V - 19-23 Settembre 2005 - Napoli
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Channeling radiation spectra (N.
(N A.
Filatova et al., Phy. Rev. Let. 48 (1982) 488)
Comm. V - 19-23 Settembre 2005 - Napoli
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Channeling radiation spectra (J.
( Bak et al.,
Nucl. Phy. B254 (1985) 491)
Photon energy spectra (yield with respect to random case) for <110>
planar channeling radiation from 6.7GeV/c positrons and electrons
traversing a 0.105 mm thick silicon crystal.
Comm. V - 19-23 Settembre 2005 - Napoli
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Energy Loss in crystals (H.Esbensen et
al., Phys.Rev B18(1978) 1054)
<110>
random
random
p 15 GeV/c
Comm. V - 19-23 Settembre 2005 - Napoli
<110>
π- 15 GeV/c
11
Critical angle
$!0.307 Z 1Z 2 /dE axial
ø crit (deg) = #
!"0.545 nZ1Z 2 a/E planar
E is the energy (MeV)
d is the atomic distance (Å) in a row
n is the atomic density in the
planes (atoms/(Å)2), n=Ndp/d3
N = atoms per unit cell
dp = interplanar distance
a = screening length (Å)
-1/3
$
0.4685
Z
2
!
a( A) = #
!
"0.4685 Z 1 + Z 2
incident ion full ionized
o
(
)
- 2/3
incident ion not full ionized
D.S. Gemmell, Rev. Mod. Phys. 46 (1974) 129
Comm. V - 19-23 Settembre 2005 - Napoli
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Critical angle
Axial-Csi [deg*sqrt(MeV)] <100>
Planar-Csi [deg*sqrt(MeV)] <100>
Axial-Csi [deg*sqrt(MeV)] <110>
Planar-Csi [deg*sqrt(MeV)] <110>
Axial-Csi [deg*sqrt(MeV)] <111>
Planar-Csi [deg*sqrt(MeV)] <111>
1.8
1.6
Critical Angle (deg*MeV^1/2)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
C
Al
Si
Fe
Ni
Cu
Comm. V - 19-23 Settembre 2005 - Napoli
Ge
W
Au
13
Channeling spectra
Comm. V - 19-23 Settembre 2005 - Napoli
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Photon Detection
NaI: Ec=12.8 MeV, dE/dx=4.8 MeV/cm, Xo=2.59 cm
CsI: Ec=11.0 MeV, dE/dx=5.6 MeV/cm, Xo=1.85 cm
Comm. V - 19-23 Settembre 2005 - Napoli
15
Photon Detection in CsI: shower profile
1GeV
100MeV
10MeV
1MeV
Comm. V - 19-23 Settembre 2005 - Napoli
16
Test beam set-up
Target (Chan. Rad.)
e±/π± 1-10 GeV/c
NaI
(CsI)
SSDs
Pb-glass
Comm. V - 19-23 Settembre 2005 - Napoli
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Q1
Far Detector Layout
Q2
Channeling radiator
Photon detector
D
Q3
Q4
beam (to experimental area)
Comm. V - 19-23 Settembre 2005 - Napoli
18
Near Detector Layout
Straw Tubes array
to detector
X-rays < 100keV
Channeling
radiator
CsI thin layers
to detector
X-rays > 100keV
and γ-rays
Channeling radiator
Comm. V - 19-23 Settembre 2005 - Napoli
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Conclusions
The channeling radiation seems to show
suitable properties for high energy
particle identification
Deeper investigation are needed, and
experimental verifications have to be
performed
A by product of this field could be the
production of polarized gamma rays to
be used as a test beam facility
Comm. V - 19-23 Settembre 2005 - Napoli
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Programma PICH
Caratterizzazione sistematica della fisica
del fenomeno (misura efficienza)
– Cristalli
– Spettri
Sviluppo di programmi di simulazione a
MonteCarlo (in ambiente GEANT)
Progettazione e sviluppo di un rivelatore
“realistico” da utilizzare come PID
Misure in laboratorio
Test su fascio
Comm. V - 19-23 Settembre 2005 - Napoli
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Milestones per il 2006
1. Assemblaggio radiatore channeling
2. Sviluppi di programmi di simulazione (in ambiente
GEANT)
3. Messa a punto del tracciatore di particelle cariche
incidenti sul radiatore e del rivelatore per la
radiazione channeling da utilizzare su un fascio
(CERN-PS e±/π± 1-10 GeV/c)
Comm. V - 19-23 Settembre 2005 - Napoli
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Backup slides
Comm. V - 19-23 Settembre 2005 - Napoli
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Composizione Gruppo
COMPOSIZIONE DEL GRUPPO DI RICERCA PICH - Gruppo V
RICERCATORE
Qua lifica
N
Cognom e
1
2
3
4
5
6
7
8
9
10
11
12
Dipe nde nti
Ruolo
Art.23
Nom e
Brigida
Fa vuzzi
Fusco
Ga rga no
Giglie tto
Giorda no
Monica
Ce cilia
Pie rgiorgio
Fa bio
Nicola
Fra nce sco
Lopa rco
Ma ra nge lli
Ma zziotta
Mirizzi
Ra inò
Spine lli
Fra nce sco
Ba rtolom e o
Ma rio Nicola
Nicola
Silvia
Pa olo
Inca richi
Rice rca
Assoc.
AsRic
P.A.
R.U.
AsRic
P.A.
AsRic
R.U.
P.O.
Ric.
P.A.
AsRic
P.O.
Numero totale dei ricercatori
Ricercatori Full Time Equivalent
TECNICI
N
Cognome
1
2
Perchiazzi
Sacchetti
Nome
Michele
Angelo
Numero totale dei Tecnici
Tecnici Full Time Equivalent
Incarichi
Ricerca
Assoc.
%
2
2
2
2
2
2
20
20
20
20
20
20
2
1
2
2
2
2
20
20
30
30
20
20
12
2.6
SERVIZI TECNICI
Qualifica
Dipendenti
Ruolo
Art.23
CTer.
CTer.
Affe r. a l
Gruppo
%
20
20
2
N
1
2
3
Denominazione
Elettronica
Officina Meccanica
Progettazione Meccanica
Mesi
uomo
3
6
3
0.4
Comm. V - 19-23 Settembre 2005 - Napoli
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Richieste
Preventivo Locale di Spesa per l'anno 2006 PICH - Gruppo V
Voci di spesa
Missioni
Interne
Missioni
Estere
Materiale di
Consumo
Descrizione di spesa
Riunioni e contatti con ditte
Test beam al CERN
Importi (kEuro)
Parziali Totale
10
10
10
10
Attrezzature e meccanica di supporto
Acquisto cristalli ed assemblaggio
Acquisto chip
Trasporto materiale ed attrezzature
10
3
2
3
Trasporti
Materiale
Inventariabile
15
3
Goniometro
Supporto di precisione
Comm. V - 19-23 Settembre 2005 - Napoli
10
5
15
25
Positron production
High-intensity positron source due to channeling
radiation for future high-luminosity e+e- linear colliders.
M. Satoh et al., NIM B227 (2005) 3
Comm. V - 19-23 Settembre 2005 - Napoli
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Bending beams (A.
( Baurichter
et al., NIM B 164-165 (2000) 27)
CERN-SPS
Planar channeled
particles follow
the bent planes
E ∼ 1012 V/m for a
<110> Si string
atom ⇒ B ∼ 103 T
Comm. V - 19-23 Settembre 2005 - Napoli
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Photon Detection in CsI:
Fired Layers
1MeV
1GeV
10MeV
100MeV
10MeV
100MeV
1GeV
1MeV
Comm. V - 19-23 Settembre 2005 - Napoli
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Near Detector Layout: multi dE/dx
Si (Ge) <100>, <110>
detectors
to detector
Comm. V - 19-23 Settembre 2005 - Napoli
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