The ALEPH detector,
in Key4hep.

JoNik4ALEPH brings ALEPH (LEP, CERN, 1989–2000) as it stood in 1994 into the Key4hep stack: the detector geometry in DD4hep, a converter of ALEPH's files, and an event display of the LEP1 data.

Open the event display →

Detector geometry

ALEPH as it stood in 1994, rebuilt as the DD4hep model ALEPH_o1_v01 in k4geo format. The geometry is generated from ALEPH's own constants database: every subdetector has its own compact file, from the VDET, ITC and TPC through the ECAL, the coil and the HCAL to the muon chambers and the luminosity calorimeters, with its materials and GALEPH's magnetic field map.

ALEPH_o1_v01 DD4hep · k4geo 0 ROOT overlaps
Cut-away render of the full ALEPH detector geometryFull detector, cut-away
Render of the ALEPH superconducting coilCoil
Render of the ALEPH hadron calorimeter barrelHCAL barrel

LEP1 event display

Every ALEPH LEP1 event from 1991–1995, read from the original files with the modern JoNik4ALEPH converter and browsable in 3D and in end and side views. You can step through runs by year and energy, filter by event type, track count and calorimeter energy, and see Durham jets and V0s. Each event is fetched on its own, about 30 kB at a time.

9,643,923 events 3,645 runs 1991–1995 Z peak, scan points, 130 & 136 GeV
Launch →

Converter validation

The JoNik4ALEPH converter revives ALEPH's original file formats inside modern infrastructure: it reads the 1990s EPIO files directly and writes them as EDM4hep for Key4hep. Here it is checked against l2e, the production EDM4hep conversion, on the same 3,893 simulated Z → qq̄ MINI-DST events: event shape, particle flow, tracks and their uncertainties, and the impact-parameter tag, each with the ratio of the two.

32 distributions JoNik4ALEPH vs l2e HVFL05, 1994 geometry
View plots →