161:). An initial deficiency of the design was that it had a comparatively large (roughly 15000μm) dead area on the part of the sensor closest to the beam. This was ameliorated, reducing the dead area to approximately 200μm, by employing a cut by a diamond saw to "dice" the sensor. Tests were carried out in 2016 to determine the efficiency of this design; and the results showed an efficiency of 97%, potentially rising by 1% because the actual sensor arrangement could use a small
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amounts by the collider magnets) and eventually hit the beam-pipe walls in places where they can be detected separately from the original beam. So this required installing new proton detectors at various distances along that beam-pipe. The existing ALFA proton detectors at ATLAS were only suitable for low-energy runs, whereas the new detectors were intended for high-energy collision measurements.
77:
by the United
Kingdom cutting funding, resulting in a decision to abandon the 420 detectors and only have the 220 ones. (The 420 detectors would in any case have presented greater technical difficulties over the 220 ones, as they would have involved also altering the liquid helium system already present at that location, and although necessary for
102:. Each of the "far" detectors also includes a time-of-flight detector, designed to reduce "pile up" by measuring the differences in particle time-of-flight on both sides of the ATLAS interaction point and comparing it to the reconstructed position of the collision vertex. The time of flight detectors comprise a microchannel-plate
85:
initial test beam that
November demonstrated that the various systems were correctly integrated, and after a kick-off meeting on 2015-02-03 the ATLAS Executive Board confirmed its decision on 2015-02-30. At the time, installation of the detectors was aimed to be completed by 2017, for use in LHC Run 2.
76:
The research and development for the AFP project began in 2004. An initial letter of intent was submitted in 2009. The initial goal was to have two sets of proton detectors positioned in groups denoted "220" (at 216m and 224m distance) and "420" (at 416m and 424m), but the project was delayed in 2010
133:
The silicon pixel sensors are positioned 2mm to 3mm from the beam. The construction of the pixel sensors is complicated by the uneven radiation doses that they receive over the course of their operating lifetimes. To harden them against this radiation their manufacture is more complex than that of a
97:
The silicon tracking detectors (SiT) used in the project were modelled on the
Insertable B-Layer (IBL) detector at ATLAS, using pixel measurements combined with magnet data to provide momentum spectrometry. In order to provide the ability to remove and re-insert the detectors they are mounted inside
137:
Their operating temperature also affects performance, and they are operated at a temperature of −20 °C with primary (Vortex Tube) and secondary (a vacuum kept between 5mbar and 30mbar) cooling systems. The vacuum system has a useful side-effect of reducing the mechanical stress caused by
175:
There are several parts of the LHC that affect the refraction of the emitted protons, including the beam separation dipole magnets, the beam focusing quadrupole magnets, and the beam collimators that protect the magnets. The divergence of the detected protons from the main proton beam depends from
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in the forward area of the machine. The particles involved travel down the forward area of the beam-pipe, where most of the energy emitted from collisions travels, but have smaller momenta than the original proton beams and have trajectories that diverge from it (because they are bent by different
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coupled to the sensors themselves, providing multiple readout channels that can be independently amplified and shaped, and that have independently adjustable discriminator levels. The chip, running off an externally supplied clock, provides 4-bit timing data for the time-over-threshold which is
84:
This reduced project went through a formal
Technical Proposal stage, and was in 2012 approved by the ATLAS Collaboration Executive Board and endorsed by the LHC Experiments Committee. There were technical reviews in 2014, with the project getting ATLAS Upgrade approval in June of that year. An
88:
The detectors at 216m are known as the "near" detectors, and the ones at 224m the "far" detectors, their separation being 15σ. They first began to collect data from LHC runs in 2016, but only in low-luminosity ones. From 2017 they were collecting data from all LHC runs.
106:(MCP-PMT) reading L-shaped quartz bars. Of particular concern is degradation caused by backscatter of positive ions, to combat which the photomultipliers are coated using atomic layer deposition. They are expected to withstand 3×10 n
63:
R&D project was an international collaboration with members from 29 institutes from 10 countries, with aim of assessing the feasibility of installing proton tagging detectors at 420m from the interaction points of the ATLAS and
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the energy loss of the collision, and the AFP detectors by the nature of their positions can only detect protons with energy losses in the range from 2% to 10% of the energy of the original beam.
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whereas the testbed was placed perpendicular to the incident radiation. This angle is the mean
Cherenkov angle, 14°, found to be the optimum angle giving a resolution of 6μm instead of the 50/
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herenkov") were based on straight quartz bars. Originally, an alternative system named GASTOV was considered, which used a gas rather than quartz to generate the
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Albrow, M. G.; Appleby, R. B.; Arneodo, M.; et al. (2009). "The FP420 R and D Project: Higgs and New
Physics with forward protons at the LHC".
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Lange, J.; Adamczyk, L.; Avoni, G.; et al. (2016-09-16). "Beam tests of an integrated prototype of the ATLAS Forward Proton detector".
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stored alongside the firing time. The sensors themselves are 336×80 pixels, with each pixel being 50×250μm on their faces and 230μm deep.
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793:. 40th International Conference on High Energy Physics, Prague, Czech Republic, 28 Jul to 6 Aug 2020. CERN. ATL-FWD-SLIDE-2020-331.
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experiments. The main area of interest that motivated the project was the study proton-proton interactions and
670:. The 27th International Workshop on Vertex Detectors, Chennai, India, 21 – 26 Oct 2018. pp. 7–16.
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The resolutions of the time-of-flight detectors were measured in tests in 2015 to be between
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This design is modelled off a 3-D sensor design that was made for the IBL by CNM (of
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762:"Overview of ATLAS Forward Proton Detectors for LHC Run3 and Plans for the HL-LHC"
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atmospheric pressure on the Roman pots, which have thin windows and floors.
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Performance of the AFP Time-of-Flight detector in 2017 LHC data
534:"Technical Design Report for the ATLAS Forward Proton Detector"
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Adamczyk, L; Banaś, E; Brandt, A; et al. (2015-05-20).
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Safety of high-energy particle collision experiments
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studies they were not necessary for other studies.)
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588:Staszewski, R. (April 2011). "The AFP project".
668:ATLAS Forward Proton detectors status and plans
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172:μm that a perpendicular orientation gives.
114:. Earlier designs for ToF called QUARTIC ("
846:European Organization for Nuclear Research
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629:"The ATLAS Forward Proton Detector (AFP)"
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633:Nuclear and Particle Physics Proceedings
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1384:The Globe of Science and Innovation
141:Operating at 40 MHz an FE-I4B
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778:Liu, Jesse Kar Kee (2021-01-25).
760:Trzebinski, Maciej (2021-03-14).
650:10.1016/j.nuclphysbps.2015.09.185
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130:recorded by the photomultiplier.
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914:Large Electron–Positron Collider
660:"ATLAS Forward Proton Detectors
773:. CERN. ATL-FWD-SLIDE-2021-046.
745:10.1088/1748-0221/11/09/P09005
1:
1404:Scientific committees of CERN
780:"Overview of AFP performance"
769:Komarek, Tomas (2021-03-14).
573:10.1088/1748-0221/4/10/T10001
1369:Worldwide LHC Computing Grid
658:Erland, P. A. (2019-02-06).
627:Grinstein, S. (2016-04-01).
70:central exclusive production
29:ATLAS Forward Proton Project
1298:Non-accelerator experiments
1081:81 cm Saclay Bubble Chamber
787:Cerny, Karel (2020-08-24).
134:simple planar arrangement.
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715:Journal of Instrumentation
543:Journal of Instrumentation
1412:
1399:Directors-general of CERN
612:10.5506/APhysPolB.42.1615
93:Equipment and experiments
1331:Future Circular Collider
953:Super Proton Synchrotron
680:. ATL-FWD-PROC-2019-001.
1326:Compact Linear Collider
962:List of SPS experiments
923:List of LEP experiments
864:List of LHC experiments
808:"ATLAS FORWARD PROTONS"
686:"FP420 R&D Project"
590:Acta Physica Polonica B
635:. 273–275: 1180–1184.
35:) is a project at the
855:Large Hadron Collider
536:. CERN-LHCC-2015-009.
479:, pp. 1181–1182.
41:Large Hadron Collider
1443:Particle experiments
1374:Microcosm exhibition
1076:30 cm Bubble Chamber
491:, p. 4–5.
320:Adamczyk et al. 2015
308:Adamczyk et al. 2015
284:Adamczyk et al. 2015
1090:Linear accelerators
737:2016JInst..11P9005L
677:10.22323/1.348.0007
641:2016NPPP..273.1180G
565:2009JInst...4T0001A
128:Cherenkov radiation
1393:(2013 documentary)
1136:Other accelerators
1071:2 m Bubble Chamber
1037:Proton Synchrotron
296:Albrow et al. 2009
143:integrated circuit
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1182:LPI (LIL and EPA)
55:History and goals
16:(Redirected from
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1340:Related articles
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1148:AC (part of AAC)
1143:AA (part of AAC)
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694:. Retrieved
690:the original
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110:/cm per 100
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59:The initial
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49:forward area
32:
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1061:PS215/CLOUD
596:(7): 1615.
516:Erland 2019
504:Erland 2019
489:Erland 2019
462:Erland 2019
432:Erland 2019
403:Erland 2019
347:Erland 2019
332:Erland 2019
79:Higgs boson
33:AFP project
1437:Categories
1066:Gargamelle
997:NA61/SHINE
728:1608.01485
696:2010-03-31
664:and Plans"
100:Roman pots
43:to detect
753:118519527
620:118158814
603:1104.1858
581:119200141
556:0806.0302
193:5 ps
185:6 ps
159:Barcelona
1422:Category
1347:LHC@home
1260:Miniball
1255:LUCRECIA
1250:ISOLTRAP
1213:facility
1265:MIRACLS
1225:COLLAPS
1122:Linac 3
1117:Linac 2
782:. CERN.
764:. CERN.
733:Bibcode
637:Bibcode
561:Bibcode
525:Sources
167:√
47:in its
45:protons
39:at the
1280:WISArD
1235:EC-SLI
1211:ISOLDE
1127:Linac4
1027:HOLEBC
933:DELPHI
894:MoEDAL
848:(CERN)
751:
662:Status
618:
579:
155:Trento
1286:WITCH
1187:n-TOF
1169:PS210
1112:Linac
1107:CLEAR
1097:AWAKE
967:AWAKE
955:(SPS)
928:ALEPH
916:(LEP)
904:FASER
899:TOTEM
874:ATLAS
869:ALICE
857:(LHC)
749:S2CID
723:arXiv
616:S2CID
598:arXiv
577:S2CID
551:arXiv
215:FP420
197:LQbar
122:ming
61:FP420
1305:CAST
1275:VITO
1230:CRIS
1177:LEIR
1163:LEAR
1102:CTF3
1056:BEBC
1051:LEIR
1039:(PS)
1022:LEBC
1017:BIBC
1002:NA62
992:NA60
982:NA49
977:NA48
972:CNGS
938:OPAL
889:LHCf
884:LHCb
195:per
187:and
116:QUAR
27:The
1270:SEC
1245:ISS
1240:IDS
1158:ISR
1046:PSB
1012:UA2
1007:UA1
879:CMS
741:doi
672:doi
645:doi
608:doi
569:doi
118:tz
66:CMS
1439::
1197:Sp
1192:SC
1153:AD
943:L3
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199:.
189:46
181:38
169:12
147:DC
120:TI
112:fb
108:eq
1201:S
1199:p
838:e
831:t
824:v
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191:±
183:±
124:C
31:(
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