T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 Particle ID
detectors of other types than RICH Introduction PID with TOF system
Scintillation counters PPC, Pestov, RPC PID with dE/dx measurements
PID with TR measurement PID with threshold-type Cherenkov counters
Slide 2 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 There
are some PIDs which are complementary to Ring Imaging type
Cherenkov detectors: Use for PID ToF, dE/dx (@ low p), Threshold
type Cherenkov Use for PID dE/dx(@ high p) TRD Use the Askaryan
effect Ultra high energy neutrino detection Introduction Slide 3 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with TOF
system Principle of Time of Flight counters Obtain mass from p (by
radii of track in a magnetic field) and v by L/t. p/p= 10 -3,
L/L=10 -3, t = 6.6 ns for L= 2 m, t ~ 100ps t/t = 1.5 % dominant
error. Particle separation capability; Slide 4 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with TOF system (Scintillator)
Time of Flight counter with scintillation counters. Well proven
technology. Mechanism of light emission in the scintillator.
Primary UV emission Secondary emission Wavelength shifter Transit
time spread limits the performance of PMT. Normal Line-focus type:
250 ps for XP2020 Fine-mesh type: 150 ps for R2490-05 Micro-channel
Plate type: 55 ps for R2809U Slide 5 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with TOF system (Scintillator)
Number of photo-electrons measured by PMTs N photon ~20,000/cm
Slide 6 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID
with TOF system (Scintillator) Expected timing resolution for long
counters ReferenceCounter size (cm)Scinti.PMT att (cm) t (meas) t
(exp) G.D.Agostini3(t) x 15(W) x 100(L)NE114XP2020200?120 60 T.
Tanimori3 x 20 x 150SCSN38R1332180140110 T. Sugitate4 x 3.5 x
100SCSN23R1828200? 50 53 R.T. Gile5 x 10 x 280BC408XP2020270110137
TOPAZ4.2 x 13 x 400BC412R1828300210240 R. Stroynowski2 x 3 x
300SCSN38XP2020180 420 Belle4 x 6 x 255BC408R6680250 90143 Slide 7
T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with TOF
system (Scintillator) NA49 Pb+Pb collision TOF-G performance
1x1.5(t)x122(L) cm 3 95 ps expected TOF-T performance 70 ps85 ps
Slide 8 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID
with TOF system (Scintillator) Belle Slide 9 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with TOF system (PPC) Time of
Flight counter with Parallel Plate Chambers. Can cover large area
(> 100 m 2 ) Operated in avalanche mode. Thickness of the gap
Thick (~ 3mm) Large signal (~10 clusters) Worse time resolution due
to long drift ~ 1ns. Thin (~ 1mm) Good time resolution; < 200 ps
Small signal ( High sparking rate. Double thin gaps (0.6 mm) Good
time resolution; < 200 ps High efficiency:.95 % Low spark rate:
10 -5. Typical detector size: 3x3 to 6x6 cm 2. Slide 10 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with TOF
system (PPC) Gases: DME/C 2 H 4 F 2 = 80/20 Having good quenching
property. 10 -5 sparking rate @ HV=3.4 kV for MIPs 100 % for slow
protons. > 95 % efficiency ALICE prototype PPC Slide 11 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with TOF
system (Pestov) Time of Flight counter with Pestov Counters (Ex.
NA49, FOPI, ALICE ToF). Excellent R&D work done by the PesToF
collaboration Idea of a spark counter with a localized (1~2 mm 2 )
discharge. ( NIM 93(1971)269) Operated in streamer/spark mode. Use
highly resistive anode: semi-conductive glass (10 9 ~ 10 10 cm).
Spark gap: 100+-2.5 m. HV > 3 kV for streamer operation. Gas:
Ar/iC 4 H 10 /C 2 H 4 /C 4 H 6 =76.9/20/2.5/0.6 @ 12 bar UV
absorptive gas. 4~5 primary electrons for MIPs. Rise-time: < 300
ps Pressure VesselCathode Resistive anode Gap (100 m) Strip Line
Spark Slide 12 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002
PID with TOF system (Pestov) Excellent timing resolution 52 ps. At
higher voltage (2xU 0 ): 25 ps is possible Long tail due to delayed
spark is observed. Need time walk correction by double threshold
discriminator: extrapolate to T 0. The tail behavior depends on the
gas mixture. t (ps) t(P1-P2) t(P-Scint) Slide 13 T. Sumiyoshi
(Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with TOF system (RPC)
Time of Flight counter with Resistive Plate Counters. Operated in
avalanche mode at atmospheric pressure. Use non-flammable gas
mixture: C 2 H 2 F 4 /SF 6 /iC 4 H 10 =85/10/5 Four 0.3 mm gaps:
Two conductive glass layers with electrically floating. Need a high
precision gap distance: 5 m Timing resolution: 90 ps @ 98 %
efficiency. With a new design: 50 ps @ 99 % efficiency. Slide 14 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with TOF
system (RPC) Multigap Resistive Plate Counters. 5 gas gaps with 220
m: 6 glass layers. Induced signal on the electrode is sum of all
the activity of all gaps. Anode (3x3 cm 2 ) Cathode (3x3 cm 2 )
Schott 8540 (2mmt) (10 10 cm) Schott A2 (0.5 mmt) (8x10 12 cm)
Schott A14 (0.5 mmt) (1.5x10 12 cm) Slide 15 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with TOF system (RPC) Timing
resolution: 70 ps @12kV -> 50 ps from MRPC Tail contribution is
only 0.16% Time walk: 25ps/kV Rate vs Timing: even at 200Hz/cm 2 70
ps with > 95 % eff. Slide 16 T. Sumiyoshi (Tokyo Metropolitan
Univ.) Jun.-6, 2002 PID with dE/dx measurements (1) Measurements of
Energy loss. Modified Bethe-Bloch equation: include the Fermi
effect At low : -1/ Minimum: at = 3 ~ 4 At high : ln 2 Saturates
due to density function: ( ) Saturates at sat.: 154 for He 230 Ar
68.4 CH 4 55.3 C 2 H 6 42.4 C 4 H 10 5.6 Si Slide 17 T. Sumiyoshi
(Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with dE/dx measurements
(2) Ecut depends on gases and tracking method etc. 10 to 100 kev
For a thin layer of gases, better energy loss calculation is
obtained by a PAI method as Allison and Cobbs approach. (by H.
Bichsel) Use photo-absorption cross-sections. At a thickness of
x>15 mm, it gives the same results by the Landau-Valilov E cut
dependence. Slide 18 T. Sumiyoshi (Tokyo Metropolitan Univ.)
Jun.-6, 2002 PID with dE/dx measurements (3) Particle Separation
Expression of dE/dx resolution (A.H. Walenta et al. NIM
161(1979)45) n: number of sampling layers, t: thickness of the
sampling layer (cm) p: pressure of the gas (atm) It doesnt depend
on n -0.5 due to the Landau flactuation. If the total lever arm
(nt) is fixed, it is better to increase n; so long as the number of
produced ion-pairs are enough in each layer. Slide 19 T. Sumiyoshi
(Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with dE/dx measurements
(4) * Data from M. Hauschild (MIN A 379(1996) 436) TypenX (cm) P
(bar) GasCalc. (%) Meas. (%) BelleDrift ch.521.51 He/C 2 H 6 =50/50
6.65.1 BabarDrift ch.401.41 He/C 4 H 10 =80/20 7.57.2 CLEOIIDrift
ch.511.41 Ar/C 2 H 6 =50/50 6.45.7 ALEPH*TPC3380.41 Ar/CH 4 =91/ 9
4.64.5 TPC/PEP*TPC1830.48.5 Ar/CH 4 =80/ 20 2.83.0 OPAL*Jet
ch.1591.04 Ar/CH 4 /iC 4 H 10 =88.2/9.8/2 3.02.8 MKII/SLC*Drift
ch.720.831 Ar/CO 2 /CH 4 =89/10/1 6.97.0 Higher pressure gives
better resolution, however, the relativistic rise saturate at lower
. 4 5 bar maybe an optimum pressure. Higher composition of
hydro-carbons gives better resolution. Belle and CLEOII. Landau
distribution (FWMH); 60 % for noble gas, 45% for CH 4,33% for C 3 H
6 Slide 20 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID
with dE/dx measurements (5) Example of the Belle PID by dE/dx (80%
truncated mean) Slide 21 T. Sumiyoshi (Tokyo Metropolitan Univ.)
Jun.-6, 2002 Chrenkov and Transition radiations Refractive index
(n( )) Frequency of photon ( ) 1 1/ Dispersion Cherenkov radiation
X-ray region Cherenkov radiation: n( ) > 1. Emits inside a
medium. Transition radiation : n( ) < 1. Only at the boundary
btw two media. Mostly x-ray region. Slide 22 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with TRD Principle of
Transition Radiation. (Frank and Ginzburg:J. Phys.9(1945)353)
Radiation at the boundary btw two media having different . A kind
of dipole radiation (charged particle and its mirror image).
Spectrum of TR 1 and 2 are Plasma frequencies of two media. ~20eV
for styrene. Energy loss by the TR increases with linearly. Slide
23 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with
TRD Direction of TR Number of TR photons; 0.59% z 2 for ~ 2keV (
=1000) Needs lots of thin material with low z (transparent for
X-rays: absorption Z 5 Lithium, polypropylene foils). Need careful
optimization for the foil thickness and the spacing. ~ 1/ 0VHV
dE/dx TR Slide 24 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6,
2002 PID with TRD Pulse height spectrum by ATLAS TRT Detector Straw
tubes: 4 mm , 40-150 cm (L) Gas mixture Xe/CF 4 /CO 2 / = 70/20/10
Without radiator With radiator 5100 Energy (keV) Slide 25 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 ATLAS-TRT
Radiators Slide 26 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6,
2002 PID with TRD Analysis methods; Needs to separate dE/dx signals
and TR x-ray signals. Total energy method Maximum Likelihood:
Truncated mean: cut at 30-40% of maximum (reduce Landau tail)
Q-method Cluster counting method N-method : set threshold at ~ a
few keV and count TR hits. Fine-grain structure: a lot of thin
radiator-layers and x-ray detectors. (Q,N) method 2dimensional
information of Q and N. Slide 27 T. Sumiyoshi (Tokyo Metropolitan
Univ.) Jun.-6, 2002 Time over threshold method (V. Bashikirov NIM
A433(1999)560 B. Dolgoshein NIM A433(1999)533) Can be used for
trigger. PID with TRD ToT TM e e Slide 28 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with TRD Time over threshold
method vs. N-method (ATLAS TRT) NIM A 474(2001) 172 For 5 GeV/c
pseudo-tracks estimated by a single straw beam test result. ToT N
clust Slide 29 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002
E715 (TRD: 30cmx12 modules=3.6 m) e/ separation:1500/1 ( e
>99.5%) No. of clusters e PID with TRD Lorentz factor ( ) Number
of detected X-rays/module E>6.5 keV Slide 30 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 TRD performance vs detector length
PID with TRD Detector length (cm) -rejection factor Slide 31 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 Si-pixel TRD
Proposed for TESLA experiment Operated in 3T magnetic field
Separate the TR and the track with a fine spatial and energy
resolution. PID with TRD Slide 32 T. Sumiyoshi (Tokyo Metropolitan
Univ.) Jun.-6, 2002 PID with Threshold type Cherenkov counters
Threshold type Cherenkov counter. Much simpler than RICH; only
ON/OFF (Npe) information. Needs highly transparent and low
refractive index materials for a radiator to separate /K at a few
GeV/c range necessary for heavy flavor physics. MaterialRefractive
index Solid Glass1.47 Silica Aerogel1.006 ~ 1.08 Liquid Water1.33
Liq. Hydrogen1.112 Gas CO2 (1 atm)1.000410@STP Air (1
atm)1.000293@STP For a /K separation at a few GeV/c region, only
the silica-aerogel is the candidate. Slide 33 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 PID with Threshold type Cherenkov
counters Aerogel radiator Hydrophobic silica aerogels by a surface
modification. Si O O OOH O O OOSi(CH 3 ) 3 Slide 34 T. Sumiyoshi
(Tokyo Metropolitan Univ.) Jun.-6, 2002 PID with Threshold type
Cherenkov counters Number of photo-electrons. More than 99 %
efficiency with Npe ~ 5, however, if we set threshold at 1 pe, then
97 %. Provide N 0 = 90/cm, L = 10 cm and n= 1.01, then 17 pe`s are
expected for = 1, however, in reality life is not so easy,
especially in a high magnetic field. Further reduction of pes is
observed in 1.5 Tesla for FMPMT: about . Light yield saturates at
around 14 cm in depth: (PMT acceptance) /(Aerogel surface area)
decreases. Slide 35 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6,
2002 PID with Threshold type Cherenkov counters ACC : K/ in 1.5 T.
Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 Detection of a
radio pulse Cherenkov radiation for an ultra-high energy neutrino
detection (GeV-TeV region can be covered by NESTOR). Askaryan
effect. (Zh. Eksp. Teor. Fiz 41(1961)616) In an electromagnetic
shower there is an asymmetry between e+ and e-, which results in a
negative net charge. An emission of coherent radio pulses is
expected for a wavelength comparable with the shower size. The
power of radio pulse is proportional to quadratic of E not to
linear. Total power W~ 5x10 -14 [E(TeV)] 2 [ max /IGHz] 2. Possible
radiators Antarctic Ice: Transparent to radio and micro waves. RICE
(Radio Ice Cherenkov Experiment) Rock salt: att > 400m @ 100
MHz. Salt dome:(1-2 km x (>10km) Higher density than ice ->
small shower size -> may coherent even at 10 GHz. Limestone:
Moon: Use a few meters of the surface regolith as the radiator and
radio telescopes as the detector. Radio pulse Cherenkov Radiation
Slide 38 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 Radio
pulse Cherenkov Radiation Observation of the Askaryan effect:
Phys.Rev.Lett.86(2001) 2802 Use silica sand as a radaiator. Power
profile (1.7-2.6 GHz). is consistent with the shower theory Slide
39 T. Sumiyoshi (Tokyo Metropolitan Univ.) Jun.-6, 2002 Summary ToF
Timing resolution of ~50 ps is obtained by small scintillators.
Almost the same or better performance is demonstrated with Pestov
counters and the newly developed RPC. dE/dx dE/dx resolution can be
improved by a selection of gas mixture. TRD Have excellent
performance for lepton (e/ ) identifications. Threshold Cherenkov
The transparent silica-aerogels covers the index gap between gases
and liquids. The hydrophobic aerogels show no degradation after 6
years operation. The Askrayan effect is observed. Now people are
using radio-pulse Cherenkov radiation. Slide 40 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 Summary Momentum (GeV/c) 10 -1 110
1 10 2 10 3 10 -2 10 -1 1 10 Detector length (m) ToF (100ps@FWHM)
RICH TR+dE/dx dE/dx 3 separation for /K Liquid-Solid Aerogel Gases
ACC Quote from the Prof. Dolgosheins talk at the last RICH
Workshop. Belle PID performance Slide 41 T. Sumiyoshi (Tokyo
Metropolitan Univ.) Jun.-6, 2002 Summary Momentum (GeV/c) 10 -1 110
1 10 2 10 3 10 -2 10 -1 1 10 Detector length (m) ToF (100ps@FWHM)
RICH TR+dE/dx dE/dx 3 separation for e/ Liquid-Solid Aerogel Gases
Quote from the Prof. Dolgosheins talk at the last RICH
Workshop.
