CNGS Primary Beam Results 2011 J. Wenninger

Beam Intensity Number of extractions: 2.552 million ! Total intensity on T40 : 4.84 x 1019 p Typical transmission of the CNGS beam through the SPS cycle ~ 95%. Injection losses ~ 6%.

SPS Extraction Before extraction the SPS beam is bumped out by ~ 31 mm to approach the magnetic septum. SPS beam position stability before extraction at 400 GeV ~ 1 mm over a run, dominated by systematic effects. The reading jumped in May after a recalibration of the BPMs. Interlock reference 31,2 mm Interlock tolerance ± 2 mm Error : rms spread

Extraction Losses In 2011 the losses on the absorber protecting the septum (TPSG) were similar to 2008-10. 7 mGray corresponds to ~ 7109 p lost on the septa, i.e. 0.035% of the extracted batch intensity. The integrated loss on the septa in 2010 is 9.8 kGray or 9.81016 p (0.02% of the total intensity on T40). Only 6 extractions (0.0005%) triggered a beam dump by the BLMs (above threshold). Interlock threshold 50 mGray Error : rms spread

TT41 reference trajectory Peak excursion at +- 3 mm in TT40.

TT40-TT41 Trajectory For most position monitors the rms position change over the entire run was only 0.1-0.2 mm. For some monitors the spread is larger, but it is due to : fluctuations of the dp/p error for the H plane, affecting BPMs at places of large dispersion. one important trajectory re-steering for both planes. Error : rms spread

Beam position on the last but one BPM in front of the target Target Beam Position The position stability of the extracted beam was excellent, ~90 mm in H and 60 mm in V over the entire run. Note that the stability is worse than in 2010 because of the choice of BPM. V Extr 1 H Extr 1 Beam position on the last but one BPM in front of the target V Extr 2 H Extr 2

Target Beam Position The position difference extr2 – extr1 has a significantly lower RMS than the raw distributions – beam positions are correlated between the 2 extractions.

Target Beam Position The beam position on target for extraction 1 and 2 are strongly correlated – as indicated by the small rms for extr2-extr1 (previous slide). In the horizontal plane the beam position drifts by 0.2 mm over the year. Note the steering is done to center the beam on the muon detectors. Error : rms spread

Red line is the interlock threshold Transfer Line Losses The transfer of the beam to the target is extremely clean and losses are rare – losses are concentrated in the extraction channel (septum). The higher losses on BLMs No. 19+20 correspond to the collimator in front of T40. Red line is the interlock threshold TT40 TT41

Collimator Losses The typical loss on the collimator in front of T40 are ~3 mGray.