Accelerator Operations and PIP Sergei Nagaitsev DOE OHEP briefing 6 March 2014

Accelerator Operations Fermilab operates a total of 16 km of accelerators and beamlines A 400-MeV proton linear accelerator (0.15 km) An 8-GeV Booster synchrotron (0.5 km) An 8-GeV accumulator ring (3.3 km) A 120-GeV synchrotron (3.3 km) A Muon Campus Delivery ring (0.5 km) Soon: the g-2 ring Transfer lines and fixed target beam lines (8 km) Two high power target stations, several low-power targets And maintains 130 buildings, structures, service bldgs,… S. Nagaitsev | Operations and PIP2

Fermilab after the Tevatron Fermilab operates the largest accelerator complex in the U.S., 2 nd largest in the world (even after termination of the Tevatron) Most economical, leanest operation of the largest accelerator complex in the US (maybe in the world) Apr 2012 – Sep 2013, ~18 months have been spent in shutdown and commissioning, adapting the accelerator complex after the end of the Tevatron era –Present mission: deliver high-intensity proton beams to explore the Neutrino Sector and rare decays Fermilab is now ready for the Intensity Frontier program and investments! S. Nagaitsev | Operations and PIP3

Fermilab Accelerator Complex Linac: NTF, MTA BNB: MicroBooNE NuMI: MINOS+, MINERvA, NOvA Fixed Target: SeaQuest, Test Beam Facility, M-Center Muon: g-2, Mu2e (future) S. Nagaitsev | Operations and PIP4

Take-home message Operational excellence is our guiding principle. –24/7 operation, 6-week/year shutdown, ~80% up-time The Proton Improvement Plan (PIP) is crucial to Fermilab accelerator operations –Reliability, availability and proton flux The success of Intensity Frontier program depends (from accelerator point of view) on: –Integrated number of protons on target (POT) –Target reliability S. Nagaitsev | Operations and PIP5

Historic Fermilab Proton Flux S. Nagaitsev | Operations and PIP6

Neutrino beam delivery over the last 15 years: Fermilab has already delivered 3.5 times the number of protons on target to its neutrino experiments than both Asia and Europe combined. No one does accelerator-based neutrinos better than Fermilab! S. Nagaitsev | Operations and PIP7 protons on target (x10 20 ) K2K 0.92 T2K 6.39 OPERA/ICARUS = total Asia + Europe NuMI BNB = total Fermilab

Proton delivery scenario (approximate) S. Nagaitsev | Operations and PIP8 POT/quarter, (x10 20 ) FY 7.5 Hz 15 Hz (after PIP) NuMI BNB mu2e g-2 SY120 “tax” Total beam thru Booster

High-power Targetry S. Nagaitsev | Operations and PIP9 Target –Solid, Liquid, Rotating, Rastered Other production devices: –Collection optics (horns, solenoids) –Monitors & Instrumentation (high radiation/temperature) –Primary Beam window –Absorbers/Collimators Facility Operations: –Remote Handling –Shielding & Radiation Transport –Air Handling –Cooling Systems –Waste stream

Neutrino Target Facility Comparison S. Nagaitsev | Operations and PIP10 NuMI (FNAL) NOvA (FNAL) T2K (J-PARC) LBNE –1.2 MW (FNAL) LBNE –2.4 MW(FNAL) SNS (ORNL) for reference CNGS (CERN) Blue – Design Beam Power Green – Actual Beam Power

Main High-Power Target Challenges S. Nagaitsev | Operations and PIP11 Thermal Shock Radiation Damage Beam Windows Also: radiation protection, remote handling

S. Nagaitsev | Operations and PIP12 NuMI and NOvA targets NuMI target must fit inside horn 1 target removed during shutdown NO v A target is installed upstream of horn 1 (neutrino energy from off-axis angle) Physics requirements allowed for changes in the design mechanically more robust 120 GeV protons Focusing Horns 2 m 675 m 15 m 30 m NuMI target Decay Pipe π-π- π+π+ νμνμ νμνμ NuMI NOvA

New Fermilab Targets in the Next Decade g-2 (previously P-bar Source Target Station) : –Commissioning in –High-Z rotating target (inconel 718 alloy) –Lithium lens at ~12 Hz (average) –Pulsed Magnet (Momentum selection) Mu2e –Commissioning in –High-Z, radiatively cooled target (tungsten) –Mounted in large SC solenoid –Only 8 kW beam power, but radiation protection issues are a challenge due to solenoid LBNE –Commissioning in –1.2 MW beam power –Low-Z target (graphite/beryllium?) –Difficult target, horn, beam window, radiation protection, remote handling challenges. S. Nagaitsev | Operations and PIP 13 p-bar lithium lens Mu2e target concept

Fermilab Booster S. Nagaitsev | Operations and PIP14 Booster is a resonant machine running at 15 Hz RF is pulsed, limited to ~7.5 Hz –at higher frequencies the cavities spark –at higher frequencies the tuners overheat –Refurbishment plan to achieve 15 Hz is part of PIP There is an RF pre-pulse associated with beam cycles –It means that the beam pulse rate is less than 7.5 Hz

Booster performance In FY14, we expect to meet the Booster beam performance metric. S. Nagaitsev | Operations and PIP15

Accelerator Performance for NuMI Started delivering protons to NuMI in 2005 – ~1.55e21 in 7 years: NO v A goal is 3.6e21 – Most intense high energy neutrino beam in the world S. Nagaitsev | Operations and PIP 16

320 kW on target Previous operation: – H- linac at ~35 mA – Charge exchange injection into Booster turns: 4.3e12 – 9 pulses (at 15 Hz) into Main Injector with RF slip stacking – Ramp to 120 GeV at 204 GeV/s and extract to NuMI target – 3.7e13 / 2.2 sec cycle 323 kW S. Nagaitsev | Operations and PIP 17

Increasing Beam Power to 700 kW Move slip-stacking to recycler 11 batch -> 12 batch Increase Main Injector ramp rate (204 GeV/s -> 240 GeV/s) 330 (380) -> 700kW with only ~10% increase in per- pulse intensity Peak intensity 10% just more frequent Main Injector Recycler S. Nagaitsev | Operations and PIP 18

The Plan Booster at 4.3e12 ppp, 7.5 Hz ✔ Begin NuMI operation with MI only ✔ –2.5e Hz (1.67 s cycle) –~290 kW peak Commission Recycler as a proton machine –Injection, extraction, instrumentation, slip stacking ✔ –Operational in May 2014 –Considering several scenarios on how to ramp the beam power up Began SY120 operation at 2e11 ✔ –Raised intensity to 2e12 in January ✔ –8e12 per spill in March S. Nagaitsev | Operations and PIP 19

Main Injector Performance We are working hard to meet the challenging POT performance metric S. Nagaitsev | Operations and PIP20

Recycler status 12 Booster batches slip- stacked in the Recycler, transferred to MI and extracted to NuMI target Next step: increase beam intensity S. Nagaitsev | Operations and PIP21

SY120 (slow extraction program) ~10% Tax on the NuMI program SeaQuest is running since November Fermilab Test Beam Facility: very successful –FY14: scheduled more than 20 experiments Meson Center test beam: –Capable of delivering 5 – 85 GeV/c secondaries of either sign. –Using the same secondary configuration as the MIPP experiment – proven design. –Initial user will be LArIAT (liquid argon detector test). –May be ready to commission in late March. –Shielding Assessment Approved S. Nagaitsev | Operations and PIP 22

PIP S. Nagaitsev | Operations and PIP23 The PIP campaign has several goals: –Increased reliability of the Linac/Booster complex –Control of beam losses –Increased proton flux Main challenge: keep beam losses constant while increasing the protons on target –Beam loss limits are set at levels for personnel safety (ALARA) and equipment serviceability

PIP profile Notes: Values are $M TPC including M&S, SWF, and indirects. Schedule is matched to the funding profile as well as it is known - though some long-lead items are not far from technically limited. FY14 is based on formal budget numbers. FY15 and FY16 are based on preliminary budget guidance. FY17 and FY18+ are base on previous funding profiles updated for the above guidance (a fully updated profile has not been produced). S. Nagaitsev | Operations and PIP 24 critical path to 15 Hz rf pulsingcritical path to 15 Hz beam and flux

Linac Modulators – From tube based to solid state S. Nagaitsev | Operations and PIP25 9-cell construction IGBT, Snubber, and Main Storage Capacitor IGBT Voltage Transients Test The Linac DTL 7835 tube modulator is ~45 years old and is increasingly difficult to maintain. Rebuild and replace (old or obsolete parts) was considered but a fully modern system was decided. Designs being considered: In house IGBT (EE/PS dept) SLAC – Marx generator

Linac 200 MHz Power Systems 7835 triode Burle 7835 triode RF power amplifier tubes for DTL: Consume 8 per year (~250k$ each new) –High vulnerability: poor lifetime, problems with supplier This has been a concern for many years for FNAL and other laboratories. After considering several options which looked at cost, labor, schedules and risk, a plan was developed and approved by laboratory management. 1.Inventory buildup: a 4-year supply of tubes 2.Design and build a new solid state modulator (keep 7835) 3.Replace tube systems in driver with Solid State when possible 4.Investigate 7835 replacement S. Nagaitsev | Operations and PIP26

Tube replacement S. Nagaitsev | Operations and PIP27 The purchase of a 200 MHz Klystron has just been completed. The device will arrive in FY15 and then tested. This will be the first of its kind and will need to be fully tested before proceeding. Some key specs: 5 MW Single Beam Klystron 450µs pulse Horizontal tube ~19 feet (floor space issues) Present socket

Booster RF cavities July 1970 Flatbed semi delivering Booster RF cavity pair Cavities built by GE S. Nagaitsev | Operations and PIP28

Booster rf cavities Booster has 22 slots for rf cavities We can not run (4.3e12) beam with fewer than 17 cavities. We have 19 cavities on hand –At any given time: 17 are installed, 2 are out for repair –each cavity requires 3 tuners. Tuners require 3 weeks to rebuild during the 10-week refurbishment process. Cavity #20 is the old 1st prototype cavity. It presently has no tuners and thus can not be used. Cavity itself is being repaired. We are planning to procure 10 new prototype tuners (enough for 3 cavities) –delivery date is not determined since some ferrite did not meet our requirements S. Nagaitsev | Operations and PIP 29

Booster PIP - Refurbishment of 40 year old cavities (facelift) S. Nagaitsev | Operations and PIP 30 Cavity Removal Cool-down Remove Tuners Rebuild - Cones & Tuners Rebuild Stems/Flanges Re-Assemble Testing Weeks 010 Cavity Removal - Stripping Tuners Rebuild Rebuild and Test

S. Nagaitsev | Operations and PIP31 Booster PIP - Cavity Refurbishment Timeline

Refurbishment: “Fun” facts and beyond All cavities in tunnel need to be refurbished before higher rep rate (15 Hz) is possible After refurbishment is completed – higher flux will require time After refurbishment is completed – the cavities will still be OLD There is likely to be failures as cavities are run harder Even if we have 20 cavities installed in the ring, this leaves us with no spares. The plan is to procure 3 more cavities in FY16,17 –same type as present cavities –larger bore –install 2 in ring as hot spares S. Nagaitsev | Operations and PIP 32

Summary Operational excellence High-power targetry PIP Fermilab is ready for Intensity Frontier investments S. Nagaitsev | Operations and PIP33