Low gain avalanche detectors can measure charged particle fluences with high speed and spatial precision, and are a promising technology for radiation monitoring and dosimetry. A detector has been ...tested in a medical linac where single particles were observed with a time resolution of 50 ps. The integrated response is similar to a standard ionising chamber but with a spatial precision twenty times finer, and a temporal precision over 100 million times better, with the capability to measure the charge deposited by a single linac pulse. The unprecedented resolving power allows the structure of the ∼3 μs linac pulses to be viewed and the 350 ps sub-pulses in the train to be observed.
Identifying charged particles using crucial features of the reconstructed waveforms is a widely exploited strategy for signal analysis in the class of pulse shape discrimination (PSD) techniques. ...This document details the design, development, and characterization of the hardware of a compact and low-power consumption telescope for data collection in space. The advanced energetic ion electron telescope (AGILE) experimental apparatus includes a stack of three 20-mm-diameter circular Si detector layers read-out by custom-made double-gain electronics that is optimized for the wide spectrum of expected energy depositions (1-100 MeV/nucleon). At the end of its front-end chain, the instrument uses a fast digitizing and sampler device based on commercial components, integrated in a control board developed by the collaboration. In this report, we motivate AGILE's hardware design and report the results obtained during the instrument's prototype laboratory test characterization.
The TOTEM collaboration has measured the proton–proton total cross section at
s
=
13
TeV
with a luminosity-independent method. Using dedicated
β
∗
=
90
m
beam optics, the Roman Pots were inserted ...very close to the beam. The inelastic scattering rate has been measured by the T1 and T2 telescopes during the same LHC fill. After applying the optical theorem the total proton–proton cross section is
σ
tot
=
(
110.6
±
3.4
) mb, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections:
σ
el
=
(
31.0
±
1.7
)
mb
and
σ
inel
=
(
79.5
±
1.8
)
mb
.
The TOTEM experiment at the LHC has performed the first measurement at
s
=
13
TeV
of the
ρ
parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at
t
=
0
, obtaining the ...following results:
ρ
=
0.09
±
0.01
and
ρ
=
0.10
±
0.01
, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the
ρ
measurement, combined with the TOTEM total cross-section measurements in an energy range larger than
10
TeV
(from 2.76 to
13
TeV
), has implied the exclusion of all the models classified and published by COMPETE. The
ρ
results obtained by TOTEM are compatible with the predictions, from other theoretical models both in the Regge-like framework and in the QCD framework, of a crossing-odd colourless 3-gluon compound state exchange in the
t
-channel of the proton–proton elastic scattering. On the contrary, if shown that the crossing-odd 3-gluon compound state
t
-channel exchange is not of importance for the description of elastic scattering, the
ρ
value determined by TOTEM would represent a first evidence of a slowing down of the total cross-section growth at higher energies. The very low-|
t
| reach allowed also to determine the absolute normalisation using the Coulomb amplitude for the first time at the LHC and obtain a new total proton–proton cross-section measurement
σ
tot
=
(
110.3
±
3.5
)
mb
, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields
σ
tot
=
(
110.5
±
2.4
)
mb
.
The TOTEM collaboration has measured the elastic proton-proton differential cross section
d
σ
/
d
t
at
s
=
13
TeV LHC energy using dedicated
β
∗
=
90
m beam optics. The Roman Pot detectors were ...inserted to 10
σ
distance from the LHC beam, which allowed the measurement of the range 0.04 GeV
2
; 4 GeV
2
in four-momentum transfer squared |
t
|. The efficient data acquisition allowed to collect about 10
9
elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-|
t
| tail. The average nuclear slope has been found to be
B
=
(
20.40
±
0
.
002
stat
±
0
.
01
syst
)
GeV
-
2
in the |
t
|-range 0.04–0.2 GeV
2
. The dip position is
|
t
dip
|
=
(
0.47
±
0
.
004
stat
±
0
.
01
syst
)
GeV
2
. The differential cross section ratio at the bump vs. at the dip
R
=
1.77
±
0
.
01
stat
has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.
Ultra Fast Silicon Detectors (UFSD) are sensors optimized for timing measurements employing a thin multiplication layer to increase the output signal. A multipurpose read-out board hosting a ...low-cost, low-power fast amplifier was designed at the University of Kansas and tested at the European Organization for Nuclear Research (CERN) using a 180 GeV pion beam. The amplifier has been designed to read out a wide range of detectors and it was optimized in this test for the UFSD output signal. In this paper we report the results of the experimental tests using 50 μm thick UFSD with a sensitive area of 1.4mm2. A timing precision below 30 ps wasachieved.
The TOTEM experiment at the CERN LHC has measured elastic proton–proton scattering at the centre-of-mass energy
s
=
8
TeV and four-momentum transfers squared, |
t
|, from
6
×
10
-
4
to 0.2 GeV
2
. ...Near the lower end of the
t
-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the
ρ
-parameter is found to be
0.12
±
0.03
. The results for the total hadronic cross-section are
σ
tot
=
(
102.9
±
2.3
)
mb and
(
103.0
±
2.3
)
mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.
In this paper we report on the timing resolution obtained in a beam test with pions of 180 GeV/c momentum at CERN for the first production of 45 μm thick Ultra-Fast Silicon Detectors (UFSD). UFSD are ...based on the Low- Gain Avalanche Detector (LGAD) design, employing n-on-p silicon sensors with internal charge multiplication due to the presence of a thin, low-resistivity diffusion layer below the junction. The UFSD used in this test had a pad area of 1.7 mm2. The gain was measured to vary between 5 and 70 depending on the sensor bias voltage. The experimental setup included three UFSD and a fast trigger consisting of a quartz bar readout by a SiPM. The timing resolution was determined by doing Gaussian fits to the time-of-flight of the particles between one or more UFSD and the trigger counter. For a single UFSD the resolution was measured to be 34 ps for a bias voltage of 200 V, and 27 ps for a bias voltage of 230 V. For the combination of 3 UFSD the timing resolution was 20 ps for a bias voltage of 200 V, and 16 ps for a bias voltage of 230 V.
The AGILE (Advanced enerGetic Ion eLectron tElescope) project focuses on the development of a compact low-cost space-based instrument to measure the intensities of charged particles and ions in ...space. Using multiple layers of fast silicon sensors and custom front-end electronics, the instrument is designed for real-time particle identification of a large variety of elements from H to Fe and spanning energies from 1 to 100 MeV per nucleon. The robust method proposed in this work uses key defining features of electronic signals generated by charged particles (ions) traveling through silicon layers to reliably identify and characterize particles in situ. AGILE will use this real-time pulse shape discrimination technique for the first time in space based instrumentation.
•Pulse shape discrimination is used to identify ions and measure their energy.•First application of pulse shape discrimination for space-based instrumentation.•Single silicon detector can be used for pulse shape discrimination.•Detailed end-to-end simulation of fast silicon detectors and electronics performed.
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