View
234
Download
0
Category
Tags:
Preview:
Citation preview
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 1013 protons @ 15
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 10-4 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 movedBLD – 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
76.281”
(1.9375 m)
sssssssssssssssssssssss
zz 10”
0.254 m
IRON
Tube 2”
0.0625” WALL 304 SS
1.5” Beam Tube
Z16.75” slot
(0.4254 m)
(17.8” total
flange to
quad steel)
QUADRUPOLE
3.005
4.563”(0.1159 m)
25.866”(0.6570 m) IRON z
4.869”(0.1126 m)
TUBE 304 SS 3.25”
0.0625” WALL
R1.625”
(0.04128 )
1.949’ (0.0495 m)
4.618”(0.1173 m)
X
2.125” min (0.0540 m)
See example coil and lamination details in text + tables
2” schedule to pipe
1.850”(0.0470 m)
Example coil(0.4096” Cu):
Gap: 2.000”
~1/16” spacing between beam tubes@entrance 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:
MW
1
MW
2
MW
3
Experimental Hall
Shi
eld
b
lock
s
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 #available Peak power specifications per component
Quadrupoles(9 200-MeV quads, 5 Pbar quads to be removed from old 8 GeV line during shutdown)
14 14 50V x 40 A
Pulsed Extraction dipoles(designed, bids are in, contract awaiting budget decisions)
2 to be built 500-1000 A (under design)
Cooling Ring dipoles(4 with refurbished coils, to be removed from A0 during shutdown)
5 >10 18V x 711 A
Air Core Trim dipoles 8 8 24V x 12A
Power supplies and power requirementsDescription # Power Supply
RequirementsPower (potential
peak power)kW
200-MeV. QuadrupolesPbar quadrupoles(many old supplies are available)
95
14 (50V x 40A) 28
Pulsed Extraction dipoles(power supply to be built in house)
2 300V x 800A700V x 800A
0.4 0.6
Cooling Ring dipole string(Trans Rex)
4 4 (18V x 711A) 51
CR dipole, single(Trans Rex or PEI)
1 18V x 400 A 7.2
Trims(need to build bulk supply)
8 8 (24V x 12A) 2.3
Total Power 90 kW
Resource Synopsis: M&S
Beamline ComponentsWith the exception of the C magnet, all beamline components are available
quadrupoles and dipolestrim magnetsdiagnosticsbeam stops
instrumentation and controls such as an eberm system
Power SuppliesWith the exception of the pulsed power supply,
all major supplies and a number of smaller ones are availabledipole supplies
misc quad and trim supplies
Vacuumion pumps are available (30 liters/min)
misc vacuum components
Water55 Linac water is available
Tevatron sled available
Resource requests: Summary
PPDC magnet
PPD Machine shop:magnet stand fabrication/modify existing stands
spool pieces
TDmagnet inspection and testing
small repairs (hoses)
AD (SWF)C magnet power supply labor
Installation:vacuum, safety, water, power supplies, beamline, controls
Muon FundsC magnet power supply parts
electricianscable tray and civil (6” bore through shield blocks)
C magnet specifications:General Value
Bpeak, range 6.0 - 6.5 kG
Repetition Rate 15 Hz
Pulse Length (half sine wave) 8.33 msec
Integrated strength, error
1st magnet 0.1668 T-m, 1% at peak
2nd magnet 2.5 1st magnet strength, 1% at peak
Good Field Region
Width, field error 0.0600 m ( 2.36”), 10-3 at peak
Gap 0.05100 m (2.008”)
Beam tube (elliptical) ~width x height 0.1173 m (4.618”), 0.0508 m (2”)
Beam tube thickness 1.59 10-3 m (0.0625”)
2nd magnet:
Tube diameter, thickness, outside beamline 0.08255 m(3.25”), 1.59 10-3 m (0.0625”)
Center to center spacing - beam tubes@upstream magnet entrance
0.1126 m 0.0003 m (4.433 0.006”)
C magnet specificatons cont…Physical Dimensions
Minimum spacing between coils (top to bottom) 0.1080 0.0064 (4.25 0.125”)
Maximum slot length
1st magnet 0.4254 m 0.0064 (16.75 0.25”)
Maximum steel Length
1st magnet 0.2604 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 gal/min @60psi and 95F
Connections, water and power Standard 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
Recommended