286
R. Forty and O. Ullaland
0
500
1000
1500
0
0.2
0.4
0.6
0.8
Time (ns)
)
3
.
3
s
p
(135.6
σ
)
4
.
0
s
p
(32.4
σ
wide
narrow
±
=
±
=
(a)
(b)
0
50
100
150
-300 -200 -100
0
100
200
300
Time with respect to start scintillators (ps)
entries/10 ps
After slewing
corrections
sigma of 48 ps
subtract jitter of start
scintillators (30 ps) gives
time resolution of 38 ps
Fig. 7.4 (a) Single photoelectron timing resolution in Burle 64-pixel MCP-PMT 85012-501 with
10 μm hole diameter. Adapted from [10]. (b) Time distribution of MRPC after slewing corrections.
Adapted from [11]
Other photon detectors are generally faster and with smaller time spread than the
PMT. See Chap. 3 for a detailed description of these devices. Below are some listed
from [8]:
• 100 μm diameter GaP SiPMT Avalanche Photo Diode operating in a Geiger
mode with active quenching [9]. Single photoelectron regime: 25 ps
• Hamamatsu H-8500 Flat panel multi anode photo multiplier tube (MaPMT). 2
SLAC measurement [8] of single photon resolution: 140 ps
• Burle 85011 photo multiplier tube with micro channel plate (MCP-PMT). 3 SLAC
measurement [8] of single photon resolution: <50 ps
A drawback with these detectors can be the non-Gaussian tails as shown on
Fig. 7.4a.
7.2.2 Parallel Plate ToF Detectors
One of the main challenges in using gas based detectors, MWPC up to spark
chambers as discussed in Chap. 3, is the time jitter caused by the spread in pulse
heights due to the long Landau tail. This can to some extent be overcome by using
many gaps and operating the detector in a regime where the pulse height is nearly
independent of the primary ionisation. However, this can seriously diminish the rate
capability of these detectors. Well adapted electronics will furthermore decrease the
time walk.
2 HAMAMATSU PHOTONICS K.K. 325-6, Sunayama-cho, Naka-ku, Hamamatsu City, Shizuoka
Pref., 430-8587, Japan.
3 BURLE INDUSTRIES, INC. 1000 New Holland Avenue, Lancaster, PA 17601-5688 U.S.A.
R. Forty and O. Ullaland
0
500
1000
1500
0
0.2
0.4
0.6
0.8
Time (ns)
)
3
.
3
s
p
(135.6
σ
)
4
.
0
s
p
(32.4
σ
wide
narrow
±
=
±
=
(a)
(b)
0
50
100
150
-300 -200 -100
0
100
200
300
Time with respect to start scintillators (ps)
entries/10 ps
After slewing
corrections
sigma of 48 ps
subtract jitter of start
scintillators (30 ps) gives
time resolution of 38 ps
Fig. 7.4 (a) Single photoelectron timing resolution in Burle 64-pixel MCP-PMT 85012-501 with
10 μm hole diameter. Adapted from [10]. (b) Time distribution of MRPC after slewing corrections.
Adapted from [11]
Other photon detectors are generally faster and with smaller time spread than the
PMT. See Chap. 3 for a detailed description of these devices. Below are some listed
from [8]:
• 100 μm diameter GaP SiPMT Avalanche Photo Diode operating in a Geiger
mode with active quenching [9]. Single photoelectron regime: 25 ps
• Hamamatsu H-8500 Flat panel multi anode photo multiplier tube (MaPMT). 2
SLAC measurement [8] of single photon resolution: 140 ps
• Burle 85011 photo multiplier tube with micro channel plate (MCP-PMT). 3 SLAC
measurement [8] of single photon resolution: <50 ps
A drawback with these detectors can be the non-Gaussian tails as shown on
Fig. 7.4a.
7.2.2 Parallel Plate ToF Detectors
One of the main challenges in using gas based detectors, MWPC up to spark
chambers as discussed in Chap. 3, is the time jitter caused by the spread in pulse
heights due to the long Landau tail. This can to some extent be overcome by using
many gaps and operating the detector in a regime where the pulse height is nearly
independent of the primary ionisation. However, this can seriously diminish the rate
capability of these detectors. Well adapted electronics will furthermore decrease the
time walk.
2 HAMAMATSU PHOTONICS K.K. 325-6, Sunayama-cho, Naka-ku, Hamamatsu City, Shizuoka
Pref., 430-8587, Japan.
3 BURLE INDUSTRIES, INC. 1000 New Holland Avenue, Lancaster, PA 17601-5688 U.S.A.