CNGS Primary Beam Results 2010 J. Wenninger

Beam Intensity The SPS beam intensity per extraction reached ~ 21013 p end of May, when MTE was stopped. Number of extractions: 2.142 million ! Total intensity on T40 : 4.041 x 1019 p Presently the intensity is limited by: Losses in the PS SPS RF (no margin). Typical transmission of the CNGS beam through the SPS cycle ~ 95%. Injection losses ~ 6%. MTE

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 extraction point was readjusted twice (~ mm). Interlock reference 30.5 mm Interlock tolerance ± 2 mm Error : rms spread

Extraction Losses To minimize activation of the extraction channel and radiation levels in ECA4, the beam gap must be as clean as possible. The gap is kept clean using the injection kicker (cleaning during the second injection). In 2010 the losses on the absorber protecting the septum (TPSG) were similar to 2008-9, below 5 mGray for a good fraction of the run. 5 mGray corresponds to ~ 5109 p lost on the septa, i.e. 0.025% of the extracted batch intensity. The integrated loss on the septa in 2010 is 8.8 kGray or 8.81016 p (0.022% of the total intensity on T40). 205 extractions (0.019%) triggered a beam dump by the BLMs (above threshold). Interlock threshold 50 mGray Error : rms spread

Extraction BLM Interlocks Interlocks due to losses in the extraction channel are not randomly distributed, but occur in ‘burst’. They are usually related to problems with the CPS leading to poor capture and beam presence in the kicker gaps. 205 extractions triggered a BLM interlock in 2010.

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

Alignment TT41 QD4105 Large misalignment wrt 2007 survey (red) in the region 4102-4105.

Reference Trajectory Horizontal and vertical reference trajectory with corrector settings. In V the corrector No. 4, MDGV.4105, that was at the limit in 2009 is now operated at ~0 kick. >> good realignment!

Target Beam Position The position stability of the extracted beam was excellent, ~50 mm in H and 70 mm in V over the entire run. No active position feedback is necessary, 1-2 small steerings / week are sufficient ! V Extr 1 H Extr 1 Beam position on the last 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. In the vertical plane the rms corresponds to the BPM resolution.

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 vertical plane the beam position jumps by 0.2 mm at the end of the MTE period (higher I?). 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.

Kicker References MKP injection settings for CNGS (kick = 49.2 kV) Delay (us) Length (us) Date Comment 1 83.7 11.0 21.04 Startup MTE 2 83.5 11.2 75.6 25.05 CT 75.3 The second kick is advanced and lengthened in order to clean the beam gap. MKE4 extraction settings for CNGS (kick = 50 kV) Extraction Delay (us) Length (us) Date Comment 1 72.0 11.5 21.04.2010 Startup MTE 71,85 30.04.2010 MTE / CT 2 59.55 12.6 59.5