applicationContext = Production

ATLAS inner detector

Assembling the Inner Detector (photo: CERN)

The inner detector is the first device to record the decay products of the proton-proton collisions. It measures the direction, the momentum and the charge of electrically charged particles that are produced when protons collide.

The inner detector consists of, from the inside to the outside, three systems:

  • Silicon pixel detector
  • Silicon strip detector
  • Transition radiation tracker

The inner detector measures the trajectories of the charged particles which are produced in the proton collisions. It can measure the particle trajectories with an accuracy of a few micrometers (one thousandth of a millimeter). The curvature of the path taken by the charged particles in the magnetic field of the detector can be used to determine their momentum and thus their energy as well.

The MPP played a crucial role in developing, building and commissioning the silicon strip detector, as well as in calibrating it for the measurements.

Current research is focusing on the development of new pixel detectors that are to be used at ATLAS in the next upgrade of the LHC accelerator.

Current research

New innermost layer of the silicon pixel detector

Insertable B-Layer
Insertable B-Layer (Photo: ATLAS/CERN)

The Insertable B-Layer (IBL for short) is the first upgrade of the Inner Detector: a new, fourth pixel detector layer which is mounted on a new, smaller diameter beam pipe.

Compared to the original pixel detector layers, the IBL pixel modules have more segments, improved radiation hardness, and are closer to the interaction zone of the proton beams. This ensures that the track reconstruction is sufficiently accurate even above and beyond the track density originally planned until the complete Inner Detector is replaced around 2025.

The MPP group contributed to several steps that were crucial to the realization of the IBL project. These included the testing of electrical components, and the production and installation of mechanical components for the novel CO2 cooling system.

Replacement of the inner detector

Around 2025, the LHC accelerator will be upgraded to allow a much higher collision rate. The plan is to replace the complete Inner Detector at the same time. In order to fulfill the demands that will then have to be met, the MPP group is developing special sensors and investigating novel connection technologies between sensors and read-out chips. The group is working in close collaboration with the Semiconductor Laboratory of the Max Planck Society, universities, the Fraunhofer Research Institution for Microsystems and Solid State Technologies, and semiconductor companies to manufacture, intensively test and further develop prototypes.

More on the modernization of the inner detector

More information on the inner detector group

Group members

name function extension www

Baron Perez, Nicolas

Student 462

Beyer, Julien-Christopher

PhD Student 462

Chatterjee, Meghranjana

Student 462

La Rosa, Alessandro, Dr.

Scientist +41.22.766.36.00

Macchiolo, Anna, Dr.

Scientist 265

Nisius, Richard, PD Dr.

Scientist 474

Pearson, Ben L., Ph.D.

Scientist 265

Events and meetings

Currently, there are no events or meetings.

Key publications

Measurement of the top quark mass in the tt¯→dilepton channel from s√=8
TeV ATLAS data
ATLAS Collaboration (Morad Aaboud (Oujda U.) et al.). Jun 7, 2016. 22 pp.
Published in Phys.Lett. B761 (2016) 350-371
DOI: 10.1016/j.physletb.2016.08.042
e-Print: arXiv:1606.02179 [hep-ex]
Cited by 12 records

Measurement of the top quark mass in the tt¯→ lepton+jets
and tt¯→ dilepton  channels using s√= TeV ATLAS data
ATLAS Collaboration (Georges Aad (Marseille, CPPM) et al.). Mar 18, 2015. 35 pp.
Eur.Phys.J. C75 (2015) no.7, 330

DOI: 10.1140/epjc/s10052-015-3544-0
Cited by 29 records

On the combination of correlated estimates of a physics observable
Richard Nisius, Feb 17, 2014. 20 pp.
Published in Eur.Phys.J. C74 (2014) no.8, 3004
arXiv:1402.4016 []
DOI: 10.1140/epjc/s10052-014-3004-2

First combination of Tevatron and LHC measurements of the top-quark mass
ATLAS and CDF and CMS and D0 Collaborations, Mar 18, 2014. 34 pp.
ATLAS-CONF-2014-008, CDF-NOTE-11071, CMS-PAS-TOP-13-014, D0-NOTE-6416, FERMILAB-TM-2582-E
arXiv:1403.4427 [hep-ex]
Detailed record - Cited by 353 records TopCite
Production and characterisation of SLID interconnected n-in-p pixel modules with 75 μm thin silicon sensors
L. Andricek, M. Beimforde, A. Macchiolo, H.-G. Moser, R. Nisius, R.H. Richter, S. Terzo, P. Weigell,
Oct 22, 2013, 14 pp.
Nucl.Instrum.Meth. A758 (2014) 30-43
arXiv:1310.5854 [physics.ins-det]
DOI: 10.1016/j.nima.2014.05.046