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CONSIDERATIONS ON WARM MAGNET MEASURED DOSES

CONSIDERATIONS ON WARM MAGNET MEASURED DOSES. Francesco Cerutti for the team. key contributions by TE-MSC Davide Tommasini and Pierre Thonet DGS-RP Julia Trummer , Christophe Tromel , Frederic Jaquenod Markus Brugger Luigi Esposito. 2012 September 3rd. OUTLINE.

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CONSIDERATIONS ON WARM MAGNET MEASURED DOSES

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  1. CONSIDERATIONS ON WARM MAGNET MEASURED DOSES Francesco Cerutti for the team key contributions by TE-MSC DavideTommasini and Pierre Thonet DGS-RP Julia Trummer, Christophe Tromel, Frederic Jaquenod Markus BruggerLuigi Esposito 2012 September 3rd

  2. OUTLINE • losses sharing (additional passive absorber in P3?) • losses scaling (warm magnet lifetime) • measurements vs expectations • reasons for caution

  3. LOSSES SHARING 2011 from the TCP BLMs Proton losses in P3 and in P7 of the same order (within a factor of 3) beam 1 / beam 2 ~ 2 in P3 and ~ 0.5 in P7 2012 (until June) from the TCP HL dosimeters Proton losses in P3 of the order of [several] % wrt P7 tight collimator settings beam 1 / beam 2 ratios consistent with 2011 P3 P7 measured MBW doses reflect the P3 vs P7 sharing: 9-16 kGy vs 100-400 kGy (~5%) for beam 1 2-5 kGy vs 330-490 kGy (~1%) for beam 2 measured MQW doses reflect the P3 vs P7 sharing 6.5 kGy vs 60 kGy (~10%) for beam 1 and the lack of TCAPC in P3: 2.5 kGy vs 45 kGy (~5%) for beam 2 > ? • additional passive absorber in P3 not justified with this P3 vs P7 sharing, BUT • the latter (dramatically) depends on the collimator settings (see 2011)

  4. LOSSES SCALING 2012 (until June) from BCT & LUMI (injected ― dumped ― collided) 1.45 [1.7] 1015 beam 1 [2] protons lost (in the collimators) for ~7fb-1 per experiment tentative extrapolations (assuming linearity between losses and luminosity, despite the energy upgrade): 1.1 1016 for 50fb-1 (one year?) projected MBW dose: 5 MGy including a factor of 2 for 7TeV operation projected MQW dose: 0.7 MGy not the factor of 2? • 6.5 1016 for 300fb-1 (until LS3??) projected MBW dose: 30 MGy • projected MQW dose: 4-5 MGy

  5. MBW MQW MEASUREMENTS VS EXPECTATIONS TCAP s h v s beam 1 IP7 TCP.D C B 6L7.B1 assuming a horizontal halo taking for 4 TeV with tight settings 2 250kGy 0.5 60 kGy for intermediate collimator settings 100-400 kGy 60 kGy peak dose one would get by normalizing to 1.4 1015beam 1 protons lost in P7 measured for 1.15 1016lost protons per beam

  6. RADIAL AND AZIMUTHAL GRADIENT (MBW) beam 1 entering 1cm x 1cm transverse resolution 250kGy 250kGy x J. Trummer assuming a horizontal halo 397.5 kGy beam 1 pointing outwards > 500 kGy 119.8 kGy ~3 MGy 0.5mm x 0.5mm transverse resolution 106.3 kGy 0.2h beam lifetime M. Brugger, Jun 2008

  7. RADIAL AND AZIMUTHAL GRADIENT (MQW) beam 1 pointing outwards beam 1 entering x 60kGy J. Trummer 1cm x 1cm transverse resolution 25.7 kGy 59.6 kGy x ~ MGy fallen off (487.3 kGy) 100.4 kGy 0.5mm x 0.5mm transverse resolution

  8. REASONS FOR CAUTION P1 (much more) controlled loss term: p-p collision debris (vertical crossing) factor 1.7 ? 289.7 kGy 171.8 kGy J. Trummer 252.7 kGy 26.5 kGy factor 10 ?? Conversely, BLMs indicates the expected left-right symmetry

  9. CONCLUSIONS • Measured doses on the MQWs in Point 3 do not exceed 10% of the ones in Point 7 • for the 2012 Feb-Jun collimator settings implying a (strongly) asymmetric sharing of losses • (in P3 few-several percent of P7). Different operation conditions can move the MQW weak point in P3, with • peak doses – for the same number of integrated losses – possibly higher than those measured in P7 • 400 kGy on the MBW and 50 kGy on the MQW for 1.5 1015 lost protons (corresponding to 7fb-1) • give a projection of 30 MGy on the MBW and 5 MGy on the MQW for 6.5 1016 lost protons (300fb-1), at • the levels of the expected failure thresholds. These estimates have to be intended in terms of orders of • magnitude due to the uncertainties in measurements and losses extrapolation (barely within a factor of 2) • Doses on the D1 MBWs in P1 (and P5) are of the same order as in the collimation region • A quite reasonable consistency with predictions from simulations was found (though this, contrary to others • already available, is far from being a clean benchmarking case) • A hard limit of 0.5 MGy on the HLDosimeters’ reading would imply their timely replacement. Calibration • up to 5 MGy viable?

  10. IP3 beam 1 h h

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