IPAC2012 - List of Authors (Drozhdin, A.I.)

Paper	Title	Page
MOPPD041	Beam Loss Protection for a 2.3 Megawatt LBNE Proton Beam	454
	R.M. Zwaska, S.C. Childress, A.I. Drozhdin, N.V. Mokhov, I.S. Tropin Fermilab, Batavia, USA
	Funding: U.S. Department of Energy. Severe limits are required for allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6·10¹⁴ protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that localized loss of a single beam pulse at 2.3 MW will result in a destructive event: beam pipe failure, damaged magnets and high levels of residual radiation inside the tunnel. A sustained full beam loss would be catastrophic. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

MOPPD082	Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array	559
	D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda Fermilab, Batavia, USA Y.A. Chesnokov, I.A. Yazynin IHEP, Moscow Region, Russia V. Guidi, A. Mazzolari INFN-Ferrara, Ferrara, Italy Yu.M. Ivanov PNPI, Gatchina, Leningrad District, Russia D. Mirarchi, S. Redaelli CERN, Geneva, Switzerland
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP). With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.

MOPPD083	Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels	562
	I.L. Rakhno, A.I. Drozhdin, N.V. Mokhov, V.I. Sidorov, I.S. Tropin Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. The MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

MOPPD084	Optimization of Extinction Efficiency in the 8-GeV Mu2e Beam Line	565
	I.L. Rakhno, A.I. Drozhdin, C. Johnstone, N.V. Mokhov, E. Prebys Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. A muon-to-electron conversion experiment at Fermilab is being designed to probe for new physics beyond the standard model at mass scales up to 10000 TeV. The advance in experimental sensitivity is four orders of magnitude when compared to existing data on charged lepton flavor violation. The critical requirement of the experiment is the ability to deliver a proton beam contained in short 100-ns bunches onto a muon production target, with an inter-bunch separation of about 1700 ns. In order to insure the low level of background at the muon detector consistent with the required sensitivity, protons that reach the target between bunches must be suppressed by an enormous factor, 109. This paper describes the results of numerical modeling with STRUCT and MARS codes for a beam line with a collimation system,** and optics that achieves an experimental extinction factor of one per billion. * R.M. Carey et al., Mu2e Proposal, Fermilab (2008). W. Molzon, “Proton Beam Extinction,” MECO-EXT-05-002 (2005). * E. Prebys, Mu2e-doc-534 (2009), http://mu2e-docdb.fnal.gov.

Paper

Title

Page

Beam Loss Protection for a 2.3 Megawatt LBNE Proton Beam

454

R.M. Zwaska, S.C. Childress, A.I. Drozhdin, N.V. Mokhov, I.S. Tropin
Fermilab, Batavia, USA

Funding: U.S. Department of Energy.
Severe limits are required for allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6·10¹⁴ protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that localized loss of a single beam pulse at 2.3 MW will result in a destructive event: beam pipe failure, damaged magnets and high levels of residual radiation inside the tunnel. A sustained full beam loss would be catastrophic. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

MOPPD082

Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array

559

D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda
Fermilab, Batavia, USA
Y.A. Chesnokov, I.A. Yazynin
IHEP, Moscow Region, Russia
V. Guidi, A. Mazzolari
INFN-Ferrara, Ferrara, Italy
Yu.M. Ivanov
PNPI, Gatchina, Leningrad District, Russia
D. Mirarchi, S. Redaelli
CERN, Geneva, Switzerland

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP).
With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.

MOPPD083

Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

562

I.L. Rakhno, A.I. Drozhdin, N.V. Mokhov, V.I. Sidorov, I.S. Tropin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. The MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

MOPPD084

Optimization of Extinction Efficiency in the 8-GeV Mu2e Beam Line

565

I.L. Rakhno, A.I. Drozhdin, C. Johnstone, N.V. Mokhov, E. Prebys
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
A muon-to-electron conversion experiment at Fermilab is being designed to probe for new physics beyond the standard model at mass scales up to 10000 TeV*. The advance in experimental sensitivity is four orders of magnitude when compared to existing data on charged lepton flavor violation. The critical requirement of the experiment is the ability to deliver a proton beam contained in short 100-ns bunches onto a muon production target, with an inter-bunch separation of about 1700 ns. In order to insure the low level of background at the muon detector consistent with the required sensitivity, protons that reach the target between bunches must be suppressed by an enormous factor, 109. This paper describes the results of numerical modeling with STRUCT and MARS codes for a beam line with a collimation system**,*** and optics that achieves an experimental extinction factor of one per billion.
* R.M. Carey et al., Mu2e Proposal, Fermilab (2008).
** W. Molzon, “Proton Beam Extinction,” MECO-EXT-05-002 (2005).
*** E. Prebys, Mu2e-doc-534 (2009), http://mu2e-docdb.fnal.gov.