Introduction for the Electrostatic Septa for Mu2e Design V. Nagaslaev ESS Engineering Review, January 18, 2017
Content for the discussions • About the review process • Introduction • Mu2e Experiment • Beam Delivery for Mu2e • Slow Extraction 2 Slow Extraction for Mu2e
The Mu2e Experiment 2.5T 1.0T 1.0T 4.6T 2.0T Direct conversion of muons into electrons in the field of nucleus • Improved sensitivity by ~4 orders of magnitude • Great potential to discover new physics • Expect to start taking data in 2021-2022 • CD3c in June 2016 • Transitioning to the fabrication phase 3 Slow Extraction for Mu2e
Pulsed beam time structure This beam structure can be realized with slow extraction from a machine with circulating narrow bunches, separated by ~1700nsec. 4 Slow Extraction for Mu2e
Mu2e Proton Delivery Two Booster “batches” are injected into the Recycler (8 GeV storage ring). Each is: Main Injector • 4x10 12 protons & • 1.7 m sec long Recycler These are divided into 8 bunches of 10 12 each The bunches are extracted one at a time to the Delivery Ring • Period = 1.7 m sec Delivery Ring As the bunch circulates, it is (aka Debuncher) resonantly extracted to produce the desired beam structure. • Bunches of ~3x10 7 protons each • Separated by 1.7 m sec Mu2e Booster 5 Slow Extraction for Mu2e
Machine cycles Full cycle in the Main Injector (1.33sec) is used to serve the neutrino experiments 12/20 of the cycle Booster and RR supply protons for the Main Injector 8/20 of the cycle can be used for muon physics Beam intensity in the Recycler during 8/20 of the cycle Beam intensity in the Delivery Ring during 8/20 of 0 1 2 3 4 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 the cycle 6 Slow Extraction for Mu2e
Slow (Resonant) Extraction Design • 3 rd Order Resonance Extraction • DR to be augmented for 3 rd order resonance: Operation point moved to 2/3 2 circuits of sextupole magnets Squeeze by ramped quads circuit Dynamic orbit control in extraction region Spill Monitoring Spill regulation by RF Knock-Out system Electrostatic septa based on thin foils • Cost effective: • Minimal changes to the legacy Debuncher lattice 7 Slow Extraction for Mu2e
Beam parameters Parameter Value Units Beam kinetic energy 8.0 GeV MI Cycle time 1.333 sec Number of spills per MI cycle 8 3.9×10 7 Number of protons per micro-pulse protons 1.0×10 12 Maximum DR Beam Intensity protons 6.0×10 12 Average spill rate protons/sec Duty Factor (Total Spill Time ÷ MI Cycle 29 % Length) Duration of one spill 43 msec Time Gap between spills 5 msec Extraction efficiency >98 % Max variation of pulse intensity ±50 % 8 Slow Extraction for Mu2e
Remodeling the Debuncher Delivery Ring • Old Injection Abort line SS20-30 • ESS New Injection (new beam line) • New Extraction in SS30 • ESS • RFKO Sextupoles: kicker • 2 families in Low Disp. • Suppress Octupole harmonic SS10-60 • Tune Quads SS40-50 • Magnetic septa (LAM+C-mag) • Dynamic bump • RFKO for spill regulation • Spill monitoring • Spill regulation 9 Slow Extraction for Mu2e
Electrostatic Septum Specifications 10 Slow Extraction for Mu2e
Main design constraints • Physics, beam parameters • Beam losses • Space available • Available technologies • Cost 11 Slow Extraction for Mu2e
Specifics of the ESS design • 2 septa @ max beta • No remotely controlled • Foil septum plane motion inside vessels: • Diffuser o Movable vessel support o Bellows for decoupling • 2 vessels identical o Adjustable field gap • Heavy shielding 12 Slow Extraction for Mu2e
ESS length specifications ESS: • Deflects beam horizontally INWARD • Need >2mrad kick ESS1 ESS2 13 Slow Extraction for Mu2e
Diffusor No diffuser Diffuser X1 Modeling: X2 X1 X2 Simulations made with sparse Mo foils Titanium foils seem to be available Carbon foils would be ideal! 14 Slow Extraction for Mu2e
Critical performance 1. Foil plane quality (mechanical tolerance) 2. Foil plane and cathode alignment (motion) 3. High Voltage 4. High Vacuum 15 Slow Extraction for Mu2e
ESS Specifications document Printouts provided 16 Slow Extraction for Mu2e
Summary This is a friendly review, hope this will be fun for you! 17 Slow Extraction for Mu2e
Recommend
More recommend
