Part II Victoria Blackmore CM32 RAL Febuary 2012 114 Standing on the shoulders Shamelessly stolen from Mark Rayners thesis p116 Design b 214 Standing on the shoulders ID: 400110
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Slide1
Step I Beam Analysis:Part II
Victoria BlackmoreCM32, RAL, Febuary 2012
1/14Slide2
Standing on the shoulders…
Shamelessly stolen from Mark
Rayner’s
thesis (p116)
Design
b
2/14Slide3
Standing on the shoulders…
Shamelessly stolen from Mark Rayner’s
thesis (p116)
Mark…
…Reconstructed the beam upstream of TOF1.
…Simulated the passage of
1 MeV slices
of this beam through G4MICE Step VI.
Demonstrated emittance reduction!What could be improved?Beam selection, RF tuning, matching…
Design
b
3/14Slide4
Beam Selection
Approximately 5’500
m
+
from the (6,200)
m
+ dataset (before TOF1):
Before muon selection
After muon selection*.Pcentre = 230 MeV,
s = 10 MeV
* Note: The higher frequency of muons in this plot is due to it being approx. 5’500
selected muons!
Example Mark “Momentum Slice”
P
centre
+/- 0.5 MeV
Very long tails
Very long tails
4/14Slide5
Simulation Procedure
Step 1 data, reconstructed before TOF1.*
*All data in this talk is from the (6, 200)
m
+
dataset.
This data set was designed to ‘match’ through a 7.5mm lead diffuser.
Interested in how it behaves with the new diffuser? Wait and see…
Remove muons with r > 150 mm, and all muons not within 0.5 ns of the reference muon at the centre of the RF cavities
(optional).
Plot
Select a 1MeV momentum slice.
Select a NF-like beam.
Tune RF to each momentum slice.
Tune RF to central momentum.
G4MICE Step VI simulation
inc.
Pb
diffuser (7.5 mm).
Apply radial cut and/or RF timing cut.
5/14Slide6
<Pz
>
6/14
b
-function is larger hereSlide7
b4D
7/14
Slide8
e
N, 4D
8/14Slide9
e
N, 4D
Inc. RF timing cut.
9/14Slide10
Tuning the Reference Muon
AKA an easy lesson in how to ‘destroy’ a beam…
10/14Slide11
Tuning the Reference Muon
AKA an easy lesson in how to ‘destroy’ a beam…
11/14
NB: Using the RF-timing cut made these plots much more ‘boring’ (i.e. normal).Slide12
A Quick Glimpse with the New Diffuser
12/14
Using the
P
centre
=
Pref
= 230 MeV Gaussian beam, with s = 10 MeV.Slide13
A Quick Glimpse with the New Diffuser
13/14
Using the
P
centre
=
Pref
= 230 MeV Gaussian beam, with s = 10 MeV.Slide14
Summary
Have expanded upon the Step I simulations through Step VI by including a Gaussian spread to the input beam.Does have an effect on beam matching.Similar emittance reduction.
The reference muon can have a large effect on the resulting emittance (cut dependent).
Step I beams were devised for the lead diffuser, which no longer exists. Their suitability for the new diffuser requires further investigation!
Still a
lot to do…
14/14