ATLAS Intensity and Efficiency Upgrade ATLAS USERS MEETING

ATLAS Intensity and Efficiency Upgrade ATLAS USERS MEETING Speaker: Mike Kelly Physics Division May 15, 2014

The Present ATLAS Accelerator Cryomodules 8 Cryomodules, 47 SC Accelerating Cavities 109 MHz Energy Upgrade cryomodule CARIBU 5. 109 MHz Module 5. 1. 2. 3. 2009 4. Split-ring cryomodules 1. 60 MHz RFQ 2. PII Cryomodules 3. 2013 1992 2013 72 MHz Module 2

Clean Assembly (left) and Cryogenics Assembly (right) for ATLAS Intensity Upgrade Cryomodule (2013) Clean room assembly (south side of beamline) Assembly stand (north side of beamline) Jan. 2013 June 2013 3

Charged Particle Acceleration in a 2 -gap Accelerating Cavity q z 4

RF Surface: (Simplified) Niobium Surface, Tc=9. 2 Kelvin Superconductivity ~40 nm 5

Electropolishing System for Low-beta Cavities A unique ANL technical capability to electropolish cavities as the final step in fabrication 6

Subcomponents: RF Couplers 4 k. W RF Power ATLAS 4 k. W Couplers 7

Issue of Maintaining the Clean Vacuum Space (a. k. a. Protection from the ATLAS Users) Cold trap Fast Valve RGA § 80 Kelvin ~1/2 meter long liquid nitrogen cooled cold traps installed at the entrance and exit for clean cryomodules § Volatiles, water, particulates adsorb to the surface of a 2. 5” cm diameter copper tube § Gate valves at the entrance and exit of the cryomodule are interlocked to cold trap ion gauges § A fast acting valve (~10 m. S) will isolate experimental areas from the accelerator in the event of a vacuum accident Cryomodule exit valve 8

The First Beam Delivered with the 72 MHz Intensity Upgrade Cryomodule First beam to experiment on Feb. 18, 2014 (Ave. Cavity Voltage 2 MV/cavity, Ave. Power per Cavity 1. 3 Watts) 20 Ne 6+ Also of note, all cavities stable with respect to quench with EACC>12 MV/m, average value for field emission onset, EACC~9 MV/m (EPEAK~45 MV/m) 9

Testing at Liquid Helium Temperatures: Q versus E (Most Commonly Used Figure of Merit) Present Operations 2. 5 MV/cavity 10

Context and Impact: SARAF Proton/Deuteron Accelerator In operation since 2009 11

Context and Impact: MSU Re-Accelerator (Re. A 3) In operation since 2011 C Planned for May 2014 12

Context and Impact: ISAC-II Heavy-ion Linac, 6 Cryomodules Commissioned 2006 -2010 13

Team for ANL SRF Cavity/Cryomodule Work Peter Ostroumov – Accelerator R&D Leader Zachary Conway – Cryomodule assembly Michael Kelly – Clean assembly, cavity testing Scott Gerbick – Electropolishing design, up-to-air system Tom Reid – Chemistry operations Ryan Murphy – High-pressure rinsing, single-cavity assembly Mark Kedzie – Vacuum systems, cryomodule assembly Sang-hoon Kim – Alignment, diagnostics Gary Zinkann – SRF Cavity Testing Brahim Mustapha – Simulation support (e. g. cavity tuning) Sergey Kutsaev – Power simulations & qualification Also Acknowledge Efforts of Steve Mac. Donald – Cryogenics upgrade Sergey Sharmentov – New RF Control System 14