Demonstration of Ionization
Cooling- the Final Step (3/2)
J. Pasternak, V. Blackmore, C. Hunt,
J-B. Lagrange, R. Preece, C. Rogers,
P. Snopok, H. Witte, J. Tarrant
28/10/2014, CM40, Rome
MICE Steps IV & V
Plan endorsed by MICE
Project Board in April 2014
Operational 2015
-Tracker1-SS1-
Operational 2018
Legend:
-SS
-FC
-AFC
CCM
-RFCC
=
=
=
=
=
Spectrometer SolenoidFocus CoilAbsorber-Focus Coil ModuleCoupling Coil Magnet
RF-Coupling Coil Module-
-Absorber-
-AFC-
MICE Step IV
Configuration
-Tracker2-
-FC-
-SS2-
-Absorber1- CCM
-Absorber2-
MICE Step V
Configuration
-Tracker1-SS1-
-FC1-AFC1-
-FC2-RFCC-
-AFC2-
-Tracker2-SS2-
Unfortunately CC and RFCC are no longer on our plan
(the DOE decision)
Please, ask the US collaborators for details.
Reference design (see J-B. Lagrange’s
talk, addressing the performance)
• Current length between the FC centres
(1.524m) This is still a free parameter!
201 MHz
cavities
Secondary
lithium-hydride
absorber
Primary
lithium-hydride
absorber
201 MHz
cavities
Secondary
lithium-hydride
absorber
Alternative design (see, C. Rogers talk)
Minimal length of the Cooling Cell (From FC centre to FC centre)- 2.18 m
201 MHz
cavities
Secondary
lithium-hydride
absorber
Primary
lithium-hydride
absorber
201 MHz
cavities
Secondary
lithium-hydride
absorber
New MICE Reference Design I
Legend:
-SS
-FC
-AFC
-RFA
Plan developed in response
to P5 recommendations
Operational 2015
-Tracker1-SS1-
Operational
2017
Spectrometer SolenoidFocus CoilAbsorber-Focus Coil ModuleRF-Absorber Module-
-Absorber-
-SS2-
-AFC-
Secondary
-Absorber1-
RFA1-
Represents
reduced cost
and technical
risk relative to
MICE Step V
-Tracker2-
-FC-
-Tracker1-
-SS1-
=
=
=
=
Secondary
-Absorber2-
Primary
-Absorber-
-FC1-
-FC2-
-AFC1-
-AFC2-
-Tracker2-
RFA2-
-SS2-
NEW
Expedited
MICE Final
Configuration
New MICE Reference Design II
•
Principal differences since review
– Spectrometer solenoids and
Focus Coils need to be separated
to properly match the optics
– US construction greatly simplified
by building two single-cavity
vessels
• Essentially just replicate the Single Cavity Test
System presently in MTA
• Allow for outboard “thin” absorbers to shield
trackers
• Incorporate all lessons learned from MTA
– Single primary LiH absorber in center of channel
(minimize UK LH2 support requirements)
– Two RF systems, each capable of
2MW@201MHz a 12MV/m with no losses and
no overhead allowance
• Deployment of additional 2 RF stations
could allow 16MV/m operation
•
These choices help limit cost,
schedule duration, and project risk
New MICE Reference Design III
• Optics Development
– Major issue is that
absorbers inside FCs
don’t work
Step V a
All coil currents within magnet specifications
Bz [T]
–
–
–
–
–
-!
–
––
––
–
!
–
–
––
–
–
!
–
––
––
–
b Step 3p/2 c
– – – – – -!
–– –– ––!
––– –––!
–– –– ––
8
Progress on Engineering
Reference: +--+ Lattice
4
B, T
3
2
1
0
1
2
4
2
0
2
4
Z, m
Reference: ++-- Lattice
B,T
Z,m
Dark current electrons emitted from
the single RF cavity (10.3 MV/m)- FES
Secondary absorber of 32.5 mm will stop these electrons!
Energy loss with the main absorber
only
E, MeV/c^2
228
226
224
222
220
218
4
2
0
2
4
Z,m
Energy loss including the secondary
absorbers
E, MeV/c^2
225
220
215
210
4
2
0
2
4
Z, m
Rematching is needed!
Secondary absorbers are 32.5 mm long LiH disks.
Effect of plastic for Secondary
Absorbers
Questions to be addressed by
November
• What is the minimal length between FCs with acceptable forces)?
Can we get better optics?
The forces are smaller, than in Step IV, so we are going to play with
this distance more.
• What is the minimal length between SS and FC? Can we get better
optics? We understand it now!
• What is the length for the secondary absorbers?
We assume 32.5 mm LiH disks- sufficient to stop DC electrons from
the cavity
• What is their cooling effect? See J-B. Lagrange’s talk.
• Can we use plastic? Yes!
• What is the performance of ++-- lattice? See J-B. Lagrange’s talk.
• Can we observe cooling in 6D? What if not?
See J-B. Lagrange’s talk.