Home | Sitemap | Contact us
this site all CERN
Physics Banner - nucleus, hadron, and QCD particle's artistic representation

Alice events from first LHC Beams

SDD data

Beam 2 was circulated for a while in the night 11/12 September.
In the figure, one of the few clean events with 7 tracks from a collision. Below, more pictures of the same tracks. Click on them to magnify

SDD data SDD data SDD data
SDD data SDD data SDD data

10 September 2008

The first LHC beams as seen by the ALICE SPD detector

The above on-line event display shows the ALICE Silicon Pixel Detector (SPD) taking data while the LHC beam reached LHC P2 in the morning of September 10 2008.

Click the graphs below to visualize the very first sign from LHC seen at 9:00:04 in SPD (left) and an on-line event display (right).

The Very First Data taken with the LHC beam.

SPD Event (first beam)

SPD Event (first beam)

The first LHC beams seen in the on-line event display of ALICE Silicon Pixel Detector (SPD).

The first LHC beams as seen by the ALICE VO detector.

Above, an on-line event display focussing on the ALICE Inner Tracking System (ITS) and the V0 detector while the first LHC beams arrive.

The on-line event display above shows the VO taking data.

Click the pictures below to see the event display of different events of the same run taken by the VO detector while the LHC beam reached P2.

V0 data V0 data

Online monitoring of the ALICE V0 detector showing the first beam circulating in the LHC at 10:27 of the 10.09.2008

At 10:26 one sees that the particle intensity doubles

The first proton beam circulates around the LHC collider.

The ALICE V0 detector consisting of two scintillator rings placed at both
sides of the interaction region at Point 2 detected thousand of particles produced every time the SPS accelerator injected bunches of protons clockwise into the first ring of the LHC.
The signals are shown as red and blue lines in the graph. With every burst the particles were going further around the ring until at 10:27 the protons traveling at speed of light came back to the ALICE position 100 microseconds after they went through the first time doubling the number of detected particles.
After a few bunches circulating through the whole machine the LHC teams and all CERN started the celebration of the first circulating beams in the LHC. At 13:04 the accelerator crews repeated this feat injecting particles anti-clockwise in the second ring and making them come around.

LHC Particles seen in FMD

LHC particles in the FMD

LHC particles in the FMD

LHC particles in the FMD

LHC Particles seen in SDD

Display of an event taken by the SDD in global partition while dumping on TD (click for larger version).

LHC particles in the SDD

The upper part shows the hits on layer 3, the lower part the hits on layer 4. The horizontal axis is the Z coordinate as measured by the anode number, the vertical axis is the phi angle as measured by the time bin in the anode. The content of each bin is the charge collected. The empty regions are modules temporary out of acquisition.

SDD data SDD data
SSD events on layers 5 (left) and 6 (right) separately, taken at the same time as the V0 and SPD detectors.