MuCool / Linac Diagnostic Beamline and MTA facility: External Beams Dept. C. Johnstone, + others Review Nov. 30, 2005

Purpose: test the basic techniques and components proposed for muon ionization cooling and provide accurate measurements of linac beam properties – important for future, stable high-intensity running of the downstream accelerators.

Description: The new beamline and facility consists of  15 Hz pulsed-magnetic extraction system which diverts an entire Linac macropulse into the new beamline  An ~50 m long beamline which feeds and ends in experiments housed in a 20’ x 40’ hall; the Mucool Test Area (MTA) Using civil construction and resources that remain from the 400-MeV Linac Upgrade; this project is considerably economical. The experimental hall is shielded and separated from the Linac by 12’ of concrete blocks— the beamline penetrates through these shield blocks to the hall  The new facility is capable of: Accepting full Linac beam intensity (1.6 x Hz) to within the radiological limits imposed by the current state of shielding and radiological controls

MTA facility: Plan View

Low-loss Beam Extraction from Linac Extraction to MTA  Begins upstream and continues downstream of 400-MeV chopper to contain H - magnetic stripping losses to level.  Requires 10” movement of Q74 upstream*  The entire Linac macropulse is extracted (the length of the macropulse may be varied from 2-50 by the 750-keV chopper. Pulsed extraction magnets:  Pulsed extraction magnets: two “C” magnets One 3  magnet upstream and one 7.5  magnet downstream; single power supply for both >1” of clearance/no conflicts with 400-MeV line No 400-MeV vacuum interruption for installation/removal Design is complete; bids are in; awaiting final division budgets *kicking beam through Q74 causes a large displacement in the 2” Linac beampipe with accompanying high losses.

400 MeV Linac Enclosure ~2m Extraction Drifts Ramp trajectories Ramp enclosure wall

H - Extraction Requirements Beam entering ramp requires ~30  of bend relative to Linac Dipole field strengths   7kG to avoid stripping H-,  upstream of chopper, ~6kG (Chopper is highly sensitive to electrons and sparking) First component to clear is Q2  Controls beam separation to Booster/diagnostic line  Cannot be moved; tricky to align  Requires 11” to clear manifolding, 13-15” beam center to center relative to transfer line Next element to clear is lambertson  Dipole (CR) conveniently fits next to transfer line between Q2 and lambertson  If CR dipoles are used (10  max) another one is required to avoid enclosure corner, 45  total is required for ramp curvature and align beam parallel with the experimental hall enclosure.

Linac modifications: Q74 moves ~10’ upstream Quad to be moved BLD – will be removed to make space for quad

Two C magnet: 10”, 25” long, 6.2 kG, 3 , 7.5  bends Chopper Pulsed Extraction System: Two C Magnets

Extracted Beam trajectories

Critical Path: C magnets ” ( m) ssssssssssssssss sssssss z z 10” m IRON Tube  2”  ” WALL 304 SS  1.5” Beam Tube  Z 16.75” slot ( m) (17.8” total flange to quad steel) QUADRUPOLE  4.563” ( m) ” ( m) IRON z 4.869” ( m) TUBE 304 SS  3.25” ” WALL R1.625” ( ) 1.949’ ( m) 4.618” ( m) X 2.125” min ( m) See example coil and lamination details in text + tables 2” schedule to pipe 1.850” ( m) Example coil (0.4096” Cu): Gap: 2.000” ~1/16” spacing between beam to magnet Beam tubes in longer magnet

Diagnostic Line Design - New design incorporates  10 m straight for transverse emittance measurements of linac beam  50 cm low beta waist at center of straight  Order of magnitude change in beam size  Access to low beta focus point  Dispersion suppression  Inexpensive straight bore through shield blocks  Simple, stable match to linac based on linac FODO cells (~90  )  High (~7m) dispersion point for momentum-spread measurement

Optical functions

Half-width beam size: MW1 MW2MW3 Experimental Hall Shield blocks

Layout, plan view Shield blocks

Operational details of Diagnostic Tune Minimum beam stay clear –  0.3” (8mm) in upstream 2” chopper mating flange and triplet quadrupoles based on 10  mm-mr linac emitance. Dispersion suppression can be checked and tuned by :  varying linac output energy and varying last CR dipole strength  Beam will be “steered” into hall using trims after the diagnostic straight Low-beta waist can be adjusted and focused onto the second multiwire (just downstream of shield blocks)  Using the quad low-beta triplet Critical Devices:  Pulsed extraction magnets  Beam stop upstream and downstream of shield blocks Occupancy and radiological controls  Beam stops provide unlimited occupancy in experimental hall  Postings, fencing, eberm module will allow us to run at ~1 Hz and full linac intensity Pulsed power supply will be hard-wired to 1 Hz.

Low-loss beam tune for MTA running Beamline can be re-tuned for MTA experiments to achieve the lowest-loss optics. One example is given below with momentum spread included. The peak beam envelope is reduced by 1 cm in the half width (2 cm full width). If a polarity flip of the quadrupole is allowed, even smaller beam envelopes can be achieved.

Component Inventory Description# required#availablePeak power specifications per component Quadrupoles (9 200-MeV quads, 5 Pbar quads to be removed from old 8 GeV line during shutdown) 14 50V x 40 A Pulsed Extraction dipoles (designed, bids are in, contract awaiting budget decisions) 2to be built A (under design) Cooling Ring dipoles (4 with refurbished coils, to be removed from A0 during shutdown) 5>1018V x 711 A Air Core Trim dipoles8 824V x 12A

Power supplies and power requirements Description#Power Supply Requirements Power (potential peak power) kW 200-MeV. Quadrupoles Pbar quadrupoles (many old supplies are available) (50V x 40A)28 Pulsed Extraction dipoles (power supply to be built in house) 2300V x 800A 700V x 800A Cooling Ring dipole string (Trans Rex) 44 (18V x 711A)51 CR dipole, single (Trans Rex or PEI) 118V x 400 A7.2 Trims (need to build bulk supply) 88 (24V x 12A)2.3 Total Power90 kW

Resource Synopsis: M&S Beamline Components With the exception of the C magnet, all beamline components are available quadrupoles and dipoles trim magnets diagnostics beam stops instrumentation and controls such as an eberm system Power Supplies With the exception of the pulsed power supply, all major supplies and a number of smaller ones are available dipole supplies misc quad and trim supplies Vacuum ion pumps are available (30 liters/min) misc vacuum components Water 55  Linac water is available Tevatron sled available

Resource requests: Summary PPD C magnet PPD Machine shop: magnet stand fabrication/modify existing stands spool pieces TD magnet inspection and testing small repairs (hoses) AD (SWF) C magnet power supply labor Installation: vacuum, safety, water, power supplies, beamline, controls Muon Funds C magnet power supply parts electricians cable tray and civil (6” bore through shield blocks)

C magnet specifications: GeneralValue B peak, range kG Repetition Rate15 Hz Pulse Length (half sine wave)8.33 msec Integrated strength, error 1 st magnet T-m,  1% at peak 2 nd magnet 2.5  1 st magnet strength,  1% at peak Good Field Region Width, field error m ( 2.36”), at peak Gap m (2.008”) Beam tube (elliptical) ~width x height m (4.618”), m (2”) Beam tube thickness 1.59  m (0.0625”) 2 nd magnet: Tube diameter, thickness, outside beamline m(3.25”), 1.59  m (0.0625”) Center to center spacing - beam magnet entrance m  m (4.433  0.006”)

C magnet specificatons cont… Physical Dimensions Minimum spacing between coils (top to bottom)  (4.25  0.125”) Maximum slot length 1 st magnet m  (16.75  0.25”) Maximum steel Length 1 st magnet m (10.25”) Required Mechanical Properties Operational flexing or fatiguing of coil+core  0.1 mil Coil or Core temperature rise, at any point <10  C, for Cooling water available ~1 and 95  F Connections, water and powerStandard Fermilab connections

06 Shutdown Tasks - complete Quadrupole move Installation of new chopper flanges and gate valve Further installation can then proceed independent of linac and as time and resources permit

Chopper Modification Drawings

New Chopper Parts: detail

Status of MTA/Linac beamline - summary Line design complete and components identified  Final layouts and full engineering in progress C magnet bids contract awarded to Everson; shipping by Jan, 2007 Q74 move and chopper modifications/gate valve completed ’06 shutdown and A0 CR dipoles pulled from Tevatron enclosure  Further installation can now proceed without vacuum interruption/disruption to Linac or Booster Installation complete in ’07 shutdown