For the purpose of future visualization of the flow field in superfluid helium-4, clusters of the triplet state excimer 4He2* are generated along the micro-scale recoil tracks of the neutron-absorption reaction n + 3He → 3T + p. This reaction is induced by neutron irradiation of the 3He fraction contained in natural isotopic abundance liquid helium with neutron beams either from the Japan Proton Accelerator Research Complex, Materials and Life Science Experimental Facility (JPARC)/Materials and Life Science Experimental Facility or from the Kyoto University Institute for Integrated Radiation and Nuclear Science. These 4He2* clusters are expected to be ideal tracers of the normal-fluid component in superfluid helium with several advantageous properties. Evidence of the excimer generation is inferred by detection of laser induced fluorescence emitted from the 4He2* clusters excited by a purpose-built short pulse gain-switched titanium:sapphire (Ti:sa) laser operating at a wavelength of 905 nm. The setup and performance characteristics of the laser system including the Ti:sa and two continuous wave re-pumping lasers are described. Detection at the fluorescence wavelength of 640 nm is performed by using optical bandpass filtered photomultiplier tubes (PMT). Electrical noise in the PMT acquisition traces could successfully be suppressed by post-processing with a simple algorithm. Despite other laser-related backgrounds, the excimer was clearly identified by its fluorescence decay characteristics. Production of the excimer was found to be proportional to the neutron flux, adjusted via insertion of different collimators into the neutron beam. These observations suggest that the apparatus we constructed does function in the expected manner and, therefore, has the potential for groundbreaking turbulence research with superfluid helium.

1.
M.
Nelkin
, “
What sense is turbulence an unsolved problem?
,”
Science
255
(
5044
),
566
570
(
1992
).
2.
V.
L’vov
and
I.
Procaccia
, “
Turbulence: A universal problem
,”
Phys. World
9
(
8
),
35
(
1996
).
3.
Y.
Pomeau
, “
The long and winding road
,”
Nat. Phys.
12
,
198
199
(
2016
).
4.
A.
Tsinober
,
An Informal Conceptual Introduction to Turbulence
(
Springer
,
Dordrecht
,
2009
).
5.
C. F.
Barenghi
,
L.
Skrbek
, and
K. R.
Sreenivasan
, “
Introduction to quantum turbulence
,”
Proc. Natl. Acad. Sci. U. S. A.
111
(
Supplement 1
),
4647
4652
(
2014
).
6.
L.
Skrbek
, “
Quantum turbulence
,”
J. Phys.: Conf. Ser.
318
(
1
),
012004
(
2011
).
7.
L.
Skrbek
and
K. R.
Sreenivasan
, “
Developed quantum turbulence and its decay
,”
Phys. Fluids
24
(
1
),
011301
(
2012
).
8.
M. S.
Mongiovì
,
D.
Jou
, and
M.
Sciacca
, “
Non-equilibrium thermodynamics, heat transport and thermal waves in laminar and turbulent superfluid helium
,”
Phys. Rep.
726
,
1
71
(
2018
), part of special issue: Non-equilibrium thermodynamics, heat transport and thermal waves in laminar and turbulent superfluid helium.
9.
A. J.
Allen
,
N. G.
Parker
,
N. P.
Proukakis
, and
C. F.
Barenghi
, “
Quantum turbulence in atomic Bose-Einstein condensates
,”
J. Phys.: Conf. Ser.
544
(
1
),
012023
(
2014
).
10.
G.
Baym
,
C.
Pethick
, and
D.
Pines
, “
Superfluidity in neutron stars
,”
Nature
224
,
673
(
1969
).
11.
D.
Page
,
M.
Prakash
,
J. M.
Lattimer
, and
A. W.
Steiner
, “
Rapid cooling of the neutron star in cassiopeia a triggered by neutron superfluidity in dense matter
,”
Phys. Rev. Lett.
106
,
081101
(
2011
).
12.
STAR Collaboration
, “
Global Λ hyperon polarization in nuclear collisions
,”
Nature
548
(
7665
),
62
65
(
2017
), Letter.
13.
P.
Sikivie
and
Q.
Yang
, “
Bose-Einstein condensation of dark matter axions
,”
Phys. Rev. Lett.
103
,
111301
(
2009
).
14.
L.
Tisza
, “
Transport phenomena in helium II
,”
Nature
141
,
913
(
1938
).
15.
L.
Landau
, “
Theory of the superfluidity of helium II
,”
Phys. Rev.
60
,
356
358
(
1941
).
16.
G. P.
Bewley
,
D. P.
Lathrop
, and
K. R.
Sreenivasan
, “
Visualization of quantized vortices
,”
Nature
441
,
588
(
2006
).
17.
T.
Zhang
and
S. W.
Van Sciver
, “
Large-scale turbulent flow around a cylinder in counterflow superfluid 4He (He (II))
,”
Nat. Phys.
1
,
36
(
2005
).
18.
R. J.
Adrian
, “
Twenty years of particle image velocimetry
,”
Exp. Fluids
39
(
2
),
159
169
(
2005
).
19.
M.
Virant
and
T.
Dracos
, “
3D PTV and its application on Lagrangian motion
,”
Meas. Sci. Technol.
8
(
12
),
1539
1552
(
1997
).
20.
D. N.
McKinsey
,
W. H.
Lippincott
,
J. A.
Nikkel
, and
W. G.
Rellergert
, “
Trace detection of metastable helium molecules in superfluid helium by laser-induced fluorescence
,”
Phys. Rev. Lett.
95
,
111101
(
2005
).
21.
J.
Gao
,
A.
Marakov
,
W.
Guo
,
B. T.
Pawlowski
,
S. W.
Van Sciver
,
G. G.
Ihas
,
D. N.
McKinsey
, and
W. F.
Vinen
, “
Producing and imaging a thin line of He2* molecular tracers in helium-4
,”
Rev. Sci. Instrum.
86
(
9
),
093904
(
2015
).
22.
W.
Kubo
and
Y.
Tsuji
, “
Lagrangian trajectory of small particles in superfluid He II
,”
J. Low Temp. Phys.
187
(
5
),
611
617
(
2017
).
23.
A.
Marakov
,
J.
Gao
,
W.
Guo
,
S. W.
Van Sciver
,
G. G.
Ihas
,
D. N.
McKinsey
, and
W. F.
Vinen
, “
Visualization of the normal-fluid turbulence in counterflowing superfluid 4He
,”
Phys. Rev. B
91
,
094503
(
2015
).
24.
D. E.
Zmeev
,
F.
Pakpour
,
P. M.
Walmsley
,
A. I.
Golov
,
W.
Guo
,
D. N.
McKinsey
,
G. G.
Ihas
,
P. V. E.
McClintock
,
S. N.
Fisher
, and
W. F.
Vinen
, “
Excimers He2* as tracers of quantum turbulence in 4He in the T = 0 limit
,”
Phys. Rev. Lett.
110
,
175303
(
2013
).
25.
W. G.
Rellergert
,
S. B.
Cahn
,
A.
Garvan
,
J. C.
Hanson
,
W. H.
Lippincott
,
J. A.
Nikkel
, and
D. N.
McKinsey
, “
Detection and imaging of He2 molecules in superfluid helium
,”
Phys. Rev. Lett.
100
,
025301
(
2008
).
26.
W.
Guo
,
J. D.
Wright
,
S. B.
Cahn
,
J. A.
Nikkel
, and
D. N.
McKinsey
, “
Metastable helium molecules as tracers in superfluid 4He
,”
Phys. Rev. Lett.
102
,
235301
(
2009
).
27.
J. W.
Keto
,
F. J.
Soley
,
M.
Stockton
, and
W. A.
Fitzsimmons
, “
Dynamic properties of neutral excitations produced in electron-bombarded superfluid helium II. Afterglow fluorescence of excited helium molecules
,”
Phys. Rev. A
10
,
887
896
(
1974
).
28.
G.
Tastevin
,
B.
Glowacz
, and
P.-J.
Nacher
, “
Using a cw 465 nm laser to probe metastable He2 Molecules
,”
J. Low Temp. Phys.
158
(
1
),
339
(
2009
).
29.
B.
Glowacz
, “
Detection of metastable He2* molecules in helium plasma
,” Ph.D. thesis,
Université Paris 6 Pierre et Marie Curie; Jagiellonian University
,
2011
, URL: https://tel.archives-ouvertes.fr/tel-01360241/document.
30.
M.
La Mantia
,
P.
Švančara
,
D.
Duda
, and
L.
Skrbek
, “
Small-scale universality of particle dynamics in quantum turbulence
,”
Phys. Rev. B
94
,
184512
(
2016
).
31.
T.
Matsushita
,
V.
Sonnenschein
,
W.
Guo
,
H.
Hayashida
,
K.
Hiroi
,
K.
Hirota
,
T.
Iguchi
,
D.
Ito
,
M.
Kitaguchi
,
Y.
Kiyanagi
,
S.
Kokuryu
,
W.
Kubo
,
Y.
Saito
,
H. M.
Shimizu
,
T.
Shinohara
,
S.
Suzuki
,
H.
Tomita
,
Y.
Tsuji
, and
N.
Wada
, “
Generation of 4He2* clusters via neutron-3He absorption reaction toward visualization of full velocity field in quantum turbulence
,”
J. Low Temp. Phys.
196
,
275
(
2018
).
32.
W.
Guo
and
D. N.
McKinsey
, “
Concept for a dark matter detector using liquid helium-4
,”
Phys. Rev. D
87
,
115001
(
2013
).
33.
A.
Tarasov
and
H.
Chu
, “
Generation of pulses with sub-nanosecond duration and sub-joule energy in gain-switched Ti:Sapphire lasers
,”
Opt. Express
27
(
3
),
3574
3582
(
2019
).
34.
E.
Räikkönen
,
M.
Kaivola
, and
S.
Buchter
, “
Compact supercontinuum source for the visible using gain-switched Ti:Sapphire laser as pump
,”
J. Eur. Opt. Soc. - Rapid Publ.
1
,
06012
(
2006
).
35.
J. J.
Zayhowski
and
A. L.
Wilson
, “
Miniature pulsed Ti:sapphire laser system
,” in
Summaries of Papers Presented at the Lasers and Electro-Optics, CLEO ’02, Technical Digest
(
Optical Society of America
,
2002
), Vol. 1, p.
428
, available at https://www.osapublishing.org/abstract.cfm?uri=CLEO-2002-CWN5.
36.
F.
Salin
and
J.
Squier
, “
Gain guiding in solid-state lasers
,”
Opt. Lett.
17
(
19
),
1352
1354
(
1992
).
37.
Y.
Saito
,
S.
Sekimoto
,
M.
Hino
, and
Y.
Kawabata
, “
Development of neutron radiography facility for boiling two-phase flow experiment in Kyoto university research reactor
,”
Nucl. Instrum. Methods Phys. Res., Sect. A
651
(
1
),
36
41
(
2011
), part of special issue: Proceeding of the Ninth World Conference on Neutron radiography (“The Big-5 on Neutron Radiography”).
38.
B.
Buyuk
and
A.
Beril Tugrul
, “
Gamma and neutron attenuation behaviours of boron carbide–silicon carbide composites
,”
Ann. Nucl. Energy
71
,
46
51
(
2014
).
39.
M. J.
Berger
,
J. H.
Hubbell
,
S. M.
Seltzer
,
J. S.
Coursey
,
J.
Chang
,
R.
Sukumar
,
D. S.
Zucker
, and
K.
Olsen
, online ,
2010
(last accessed September 11, 2019).
40.
P. C.
Hendry
and
P. V. E.
McClintock
, “
Continuous flow apparatus for preparing isotopically pure 4He
,”
Cryogenics
27
(
3
),
131
138
(
1987
).
41.
M. E.
Hayden
,
G.
Archibald
,
P. D.
Barnes
,
W. T.
Buttler
,
D. J.
Clark
,
M. D.
Cooper
,
M.
Espy
,
R.
Golub
,
G. L.
Greene
,
S. K.
Lamoreaux
,
C.
Lei
,
L. J.
Marek
,
J.-C.
Peng
, and
S. I.
Penttila
, “
Neutron-detected tomography of impurity-seeded superfluid helium
,”
Phys. Rev. Lett.
93
,
105302
(
2004
).
42.
R. P.
Behringer
and
H.
Meyer
, “
Diffusive relaxation processes in liquid 3He-4He mixtures. II. Superfluid phase
,”
J. Low Temp. Phys.
46
(
5
),
435
450
(
1982
).
43.
D.
Murphy
and
H.
Meyer
, “
Heat transport in dilute mixtures of 3He in superfluid 4He
,”
J. Low Temp. Phys.
107
(
1
),
175
196
(
1997
).
44.
S. K.
Lamoreaux
,
G.
Archibald
,
P. D.
Barnes
,
W. T.
Buttler
,
D. J.
Clark
,
M. D.
Cooper
,
M.
Espy
,
G. L.
Greene
,
R.
Golub
,
M. E.
Hayden
,
C.
Lei
,
L. J.
Marek
,
J.-C.
Peng
, and
S.
Penttila
, “
Measurement of the 3He mass diffusion coefficient in superfluid 4He over the 0.45–0.95 K temperature range
,”
Europhys. Lett. (EPL)
58
(
5
),
718
724
(
2002
).
You do not currently have access to this content.