Muon Catalyzed Fusion (µCF) K. Ishida (RIKEN) Principle of µCF Topics D2/T2 α-sticking, dtµ formation T2 tt-fusion, He accumulation µCF with high intensity muon beams in collaboration with K. Nagamine 1,2 *, T. Matsuzaki 1 , S. Nakamura 1 **, N. Kawam ura 1 *, Y. Matsuda 1 , A. Toyoda 3* , H. Imao 3 , M. Kato 4 , H. Sugai 4 , M. Tanase 4 , K. Kudo 5 , N. Takeda 5 , G.H. Eaton 6 1 RIKEN, 2 KEK, 3 U. Tokyo, 4 JAERI, 5 AIST, 6 RAL present address *KEK, **U. Tohoku NuFact02 4 July 2002 Imperial College, Londo
NuFact02 4 July 2002 Imperial College, London. Muon Catalyzed Fusion (µCF). K. Ishida (RIKEN) Principle of µCF Topics D2/T2 α-sticking, dtµ formation T2tt-fusion, He accumulation µCF with high intensity muon beams in collaboration with - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Muon Catalyzed Fusion (µCF)
K. Ishida (RIKEN)
Principle of µCFTopics
D2/T2 α-sticking, dtµ formationT2 tt-fusion, He accumulation
µCF with high intensity muon beams
in collaboration withK. Nagamine1,2*, T. Matsuzaki1, S. Nakamura1**, N. Kawamura1*,Y. Matsuda1, A. Toyoda3*, H. Imao3, M. Kato4, H. Sugai4, M. Tanase4, K. Kudo5, N. Takeda5, G.H. Eaton6 1RIKEN, 2KEK, 3U. Tokyo, 4JAERI, 5AIST, 6RALpresent address *KEK, **U. Tohoku
NuFact02 4 July 2002 Imperial College, London
Principle of Muon Catalyzed Fusion (µCF)
1.Muon injected in D2+T2 mixture
behaving like heavy electron
2.Coulomb barrier shrinks in small dtµ molecule(nuclear distance ~ 1/200 of DT molecule)
3.Muon released after d-t fusion and find another d-t pair to fuse→Muon working as catalyst of d-t fusion
d t
μ-tμ
dμ
μdt μ
nα
μ
freemuon
muontransfer(~5 10x -9 )s
muonicmoleculeformation (~5 10x -9 )s
nuclearfusion(~10 -12 )s
muonic atomformation(~10 -11 )s
α stickingωs
0~0.9%
reactivation( ~0.35)R
recycle(~99.5%)
αμ17.6 MeV x ?
energy output
cost for muon
production~5.3 GeV
injectedmuon d
ddμ
tt μ
Kα/K β-X ray
14MeVneutron
compositmolecule
μ
αμμ
3Heμ
3Heμ
µCF (Motivation)
Exotic atoms and moleculesatomic physics in small scalerich in few body problems
dt fusion and alpha-stickingdtµ levels and formationatomic collisions, muon transfer
cooperation between experiment and theory~40%:60% in µCF01 Conference
Prospect for applications (fusion neutron source, fusion energy)muon production cost (~5 GeV)
vsfusion output (17.6 MeV x 200?)
very close to breakeven
tμ
dμ
μdt μ
nα
μ
dtµformation
nuclearfusion
effectivestickingωs=(1- )R ωs
0
αμ17.6 MeV x Yn
energy output
injectedmuon
d
Kα/K β-X ray
14MeVneutron
3Heμ transfer
to He
Maximizing µCF CycleObservables
(1) Cycling rate c (↑) (vs 0: muon life)rate for completing one cycledtµ formation tµ + D2 →[(dtµ)dee]
(2) Muon loss W (↓ )muon loss per cyclemuon sticking to α-particle is the main loss
Number of fusion per muon
Yn = φλc/λn = 1/ [(λ0/φλc)+W] (↑)
tμ
dμ
μdt μ
nα
μ
dtµformation
nuclearfusion
effectivestickingωs=(1- )R ωs
0
αμ17.6 MeV x Yn
energy output
injectedmuon
d
Kα/K β-X ray
14MeVneutron
3Heμ transfer
to He
Present status of µCF understanding
dtµ molecule formationunexpectedly high dtµ formation rate (109 /s) was understood by Vesman mechanism of resonant molecular formationstill many surprises
density dependencelow temperature & solid state effect
ΔEν = ε11dtμ + ε0
tμ
tμ + (D2)νiKi Å® [(dtμ)11dee]*vfKf
tμ
d d dtμd
e-
e-
e-
e-
Å®Å{μ
μ
dtμU
R
D2
ΔEνε11dtμ
ε0tμ
ν = 0
ν = 1
ν = 2
J,ν = (0,0)
J,v=(1,1)ν = 0
[(dtμ)dee]
~0.3eV
Present status of µCF understanding
αμ Sticking probability
main source of muon loss from µCF cycle
discrepancy between theory and experiments
n
free muon(~10keV)
initial sticking:
thermalized effective sticking: s=(1-R) s
0
reactivation
3.5MeV
14.1MeV -
-
R~0.35
s0~0.9%
ωs0:Theory
ωs :Theory
Muon to alpha sticking and X-rays
Main loss process of muons W = ωs + ...
Ultimate obstacle for µCF ( Yn < 1/ωs)
Previous experiments: determine W from
fusion neutron and subtract possible other losses
Excita-tion
Deexcita-tion
Ionization
1S
n=3
n>3
Thermalization
Transfer
dμ, tμ
InitialSticking αμ
γKα
ωs0
0.68%
0.10%
0.03% 2p2s
0.09%
: ReactivationR
γKβ
Effective Sticking
ωs = (1-R) ωs0
~ 0.35
Final Sticking (← neutron yield ) ωs = (1-R) ωs
0
Initial sticking ωs0 ← dt-fusion in dtμ
Reactivation R ← αμ (3.5MeV) atomic process
X-ray measurementY(Kα) = γKaωs
0, Y(Kβ) = γKβωs0
Direct measurement of initial sticking ωs0
αμ excited states and its time evolvement ( Kβ/Kαratio, Doppler width)
Use of strong pulsed muon beam Tritium handling facility Detectors with calibration (fusion neutrons, X-rays) Stopping muon number(µe decay and µBe X-ray) Determine basic parameters and find the condition for improving efficiency
λc, W , X-ray emission → α sticking probability and other loss processes reaction rates (dtµ formation rate, muon transfer etc)
0 100mm
Muon
90 400
Neutron detectors
µecounters
D-TTarget
Si(Li) X-raydetector
BeWindows
840
Superconductingmagnet
~~
~~
~~
Muon to alpha stickingObservation of x-rays from μα sticking under huge bremsstrahlung b.g.with intense pulsed muon beam at RIKEN-RAL Y(Kα),Y(Kβ): αβ x-ray per fusion
Brems b.g.
time
d.c. muon beam
gate time20µs 20ms
pulsed muon beam
Kα,Kβ-X rays
14MeVneutron
dtμ
nα
μ
μ
dμ
tμ
αinitial sticking
thermalized αμ
effective sticking:ωs=(1-R)ωs
0
reactivation3.5MeV
μ-
R~0.35
αμ
W = (1-λ0/λn)/Yn
λn, Yn
ωs = W - Wdd - Wtt ..
γ n
free μ−
initial sticking
effective sticking
TheoryExperiment
Present Status of Neutron and X-ray Measurements
Measure neutron (effective sticking)and αμX-ray (initial sticking)in the same experiment