PNPI-ILL-PTI collaboration
at ILL reactor in Grenoble
and
at WWR-M reactor in Gatchina
Present status
and
future prospects of
“Gatchina double chamber EDM spectrometer”
Serebrov A.P. PNPI 4 July 2012
2
3
Neutron EDM Experimental limit (e·cm)
History of nEDM measurements. Results and prospects
of PNPI-ILL-PTI collaboration
10
-20
10
-21
10
-22
10
-23
10
-24
10
-25
10
-26
10
-27
10
-28
Theoretical
Prediction:
- Electromagnetic
MIT-BNL
ORNL-Harvard
ORNL-ILL...
ILL-Sussex-RAL...
PNPI
- Weinberg Multi-Higgs
Present limit
Estimation of accuracy at ILL
!
- Minimal SUSY
Cosmology
- Left-Right Symm.
Estimations of accuracy at super UCN source
in Gatchina
!!
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020
Year
4
5
Neutron EDM Experimental limit (e·cm)
History of nEDM measurements. Results and prospects
of PNPI-ILL-PTI collaboration
10
-20
10
-21
10
-22
10
-23
10
-24
10
-25
10
-26
10
-27
10
-28
Theoretical
Prediction:
- Electromagnetic
MIT-BNL
ORNL-Harvard
ORNL-ILL...
ILL-Sussex-RAL...
PNPI
- Weinberg Multi-Higgs
Present limit
Estimation of accuracy at ILL
!
- Minimal SUSY
Cosmology
- Left-Right Symm.
Estimations of accuracy at super UCN source
in Gatchina
!!
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020
Year
6
ILL UCN facilities - PF2 MAM
(in the past)
NESSIE
vacuum
vessel
platform
(iron)
7
The allocation scheme of the multi-chamber EDM
spectrometer at PF2 UCN facility
8
Installation of non-magnetic platform
9
First experiment
on the non-magnetic platform
History of mirror ideas
Review (259 references)
hep-ph/0606202 v2 Dec 2006
Physics-Uspekhi 50 (2007) 380
Coexistence is possible, transitions are complicated
=?
mirror world
coexistence
world
L
R
L
610-10
mirror
particles
particles
mirror
antiparticles
antiparticles
mirror antiworld
annihilation!!
Coexistence is not
possible
R
antiworld
How to observe n-n transitions
The evolution of nonrelativistic n-n system in the external magnetic field B is
described by the effective Hamiltonian :

P2

m


i
  (  B )  V

2
m
2
H 

m



m


2

P

m 
 i V 
2m 
2

H=0 (H<10-4 Gauss)
H0 (H0.2 Gauss)
n
Energy states of ordinary and mirror neutron are degenerated when magnetic field
H=0, and transitions are possible. Due to magnetic field energy states of neutron can
be shifted and transitions to mirror state will be suppressed.
Assembling of magnetic shielding and
vacuum chamber
of EDM spectrometer
13
Preparation of n  n experiment at ILL
14
Assembling on the platform
15
Go back to EDM
Assembly of double-chamber EDM spectrometer in
summer 2008 in the interval between reactor cycles
18
August 2008. Completion of main part of assembly.
19
September 2008 - Assembly and testing of detectors, magnetometers and electronics.
October 2008 - Start of the first measurements with the neutrons
20
Direct measurements of UCN density in the EDM
spectrometer entrance and at the UCN turbine exit
12,5
exp 
N 0 ( st   fill )( st   emp )
V
st2
10,0
Calculation
3/2
AE
-3
=7.5 cm
7,5
3
[cm ]
EDM sp. entrance
5,0
Turbine exit
2,5
0,0
0,0
0,5
1,0
Ec[m]
21
1,5
2,0
2,5
Resonance curve of the double-chamber
EDM spectrometer, T(stor)=20s
Det1+Det2
8000
Counts per cycle
7000
6000
5000
4000
3000
2000
53.0
53.2
53.4
53.6
53.8
Frequency [Hz]
22
54.0
54.2
Resonance curve of the double-chamber
EDM spectrometer, T(stor)=20s
0
Phase 0
0
Phase 180
8000
Counts per cycle
7000
6000
5000
4000
3000
2000
53.50
53.55
53.60
53.65
53.70
53.75
53.80
53.85
53.90
Frequency [Hz]
First estimation of EDM sensitivity
(1,5 – 2,0) ∙ 10-25 e∙cm/day
for 20kv/cm , T (stor)
= 60s, 4 detectors
23
Possible long-range interaction (axion-like interaction)
between nucleons
A.A. Anselm JETP Lett.
v36 N2 (1982)
g (1)
s
J.E. Moody and Frank Wilczek
Phys. Rev. D v30 N1 (1984)
2
1
i 5g(2)
p
g (1)
s
g (2)
s
2
1
r
(2)

g (1)
g
V(r)   s s e 
4r
V(r)  g g
(1) (2)
s
p
24
 2r
8M 2
1   r
1
 r  r 2  e


Direct experimental limits for gSgP and
“axion window” of mass or distance of interaction
2  103 cm    2 cm

25
m Ac
Additional effective magnetic field in EDM spectrometer

z

V(z)  5.2  10  eV / cm    cm  e g S g P   n H eff
5
z

z

5.2  10 e gS g P
16

 8.7  10  G / cm    cm  g Sg Pe 
n
5
Heff

n  6  1012 eV / G
UCN depolarization on
vertical walls
A. Serebrov
(arxiv:0902.1056)
shift of resonances on
horizontal walls
O. Zimmer
(arxiv:0810.3215)
26
Measurement of UCN depolarization in EDM spectrometer
0,80
0,75
Polarization
0,70
H0 Upper chamber
double H0 Upper chamber
H0 Lower chamber
double H0 Lower chamber
0,65
0,60
0,55
Data: H0_P1
Data: DounledH0_P1
Data: H0_P2
Data: DounledH0_P2
Chi^2/DoF= 1.69316
R^2
= 0.95239
Chi^2/DoF= 0.36793
R^2
= 0.9918
Chi^2/DoF= 1.27029
R^2
= 0.9779
Chi^2/DoF= 1.3572
R^2
= 0.98598
A1
t1
A1
t1
A1
t1
A1
t1
0.757 ±0.00217
784.282 ±51.57
0.774 ±0.0019
768.162 ±44.13
0.7606 ±0.00168
789.846±40.291
0.7873 ±0.00147
697.755±27.418
0,50
0
10
20
30
40
50
Storage
time
27
60
70
80
90
Measurement of resonance shift at the change of direction of
magnetic field in EDM spectrometer
5500
D1
D2
5000
4500
4000
3500
3000
2500
2000
1500
1000
119,0
119,5
120,0
120,5
121,0
121,5
122,0
Div.coeff.
magnetic field down
28
Measurement of resonance shift at the change of direction of
magnetic field in EDM spectrometer
D1
D2
4500
4000
3500
3000
2500
2000
1500
1000
119,0
119,5
120,0
120,5
121,0
121,5
122,0
Div.coeff
magnetic field up
29
Result of measurements
(JETP Letters, 2010, Vol. 91, no. 1, pp. 6-10)
mA, eV
-1
-2
10
-3
10
-4
10
-5
10
-6
10
10
-13
10
grav. levels [5
]
3
-15
10
this
w
-17
10
ork
-19
1
-21
2
gSgP
10
10
5
-23
10
6
4 [12]
SN1987A [13]
CDM [13]
-25
10
-27
10
.
-29
10
-4
10
-3
10
-2
10
-1
10
0
10
1
10
2
10
range , cm
1 – UCN depolarization (this work); 2 – shift of resonance (this work); 3 – gravitational levels [5]; 4 – [12]; 5 – astrophysical
restriction of axion mass [13]; 6 – cosmological restriction of axion mass in model of cold dark matter [13]. On the upper
  mA c
horizontal axis the mass range of intermediate boson (axion) is shown in correspondence with formula
30
Again go back to EDM
Preparation of Cs-magnetometers at PTI
33
8 (4x2)Cs-magnetometers inside EDM spectrometer
34
System of optical pumping with light guides
35
Stabilization of magnetic field during resonance measurements
(system of stabilization of resonance conditions + feedback by means
of current coils)
quiet magnetic situation
Up
Down
Mean
1851
1850
Magnetic field [nT]
1849
1848
1847
1846
1845
1844
1843
12:00
14:00
16:00
18:00
20:00
22:00
Time
36
Stabilization of magnetic field during resonance measurements (system of
stabilization of resonance conditions + feedback by means of current coils)
full day tests of bridge crane
Up
Down
Mean
1850
1849
Magnetic field [nT]
1848
1847
1846
1845
1844
1843
12:00
14:00
16:00
Time
37
18:00
20:00
22:00
The influence of external magnetic fluctuations on stability of resonance
conditions in a spectrometer.
(factor of stabilization by mean of 8 Cs-magnetometers is about 10 – 15
times)
crane operation
FM [Hz]
54.377
-3
1.7*10
54.376
54.375
b) FN is the frequency
measured by the
additional Cs
magnetometers in
working volume;
54.073
FN [Hz]
a)FM is the average
frequency measured by
means of eight Cs
magnetometers;
54.072
54.071
F [Hz]
Difference FN – FM.
-0.304
-4
1.3*10
-0.305
-0.306
0
20
40
60
80
Number of measurement 38
100
For reduction of UCN losses the neutron guides and storage chambers (glassceramics rings and electrodes) were sent to PNPI where their surfaces were cleaned
and freshly coated with 58Ni-Mo and BeO, Be, respectively.
PNPI installations for coating of neutron guides
and storage chamber.
40
Coating facilities at PNPI (installation for
coating of flat surface of UCN guides and electrodes
(Ni58Mo, Be) and cylindrical surface of UCN trap (BeO)
ion gun
sputtering magnetron
rotating table
Near installation
A.Kharitonov, E.Siber, O.Rozhnov
41
Coating facilities at PNPI (installation for
coating of cylindrical UCN guides inside (Ni58Mo, Be))
moveable tube support
magnetron
Near installation
M.Lasakov, A.Vasiliev
ion gun
Glass ceramics rings (insulators)
and new entrance guide after
coating by BeO and 58Ni-Mo
UCN guide with a big diameter
(replica technology)
Installation for coating of Ni58Mo
on the float glass
foil after separation
from glass
(size 700x470 mm2)
preparation of
a UCN guide
UCN guides of
different diameters
43
Electronics for magnetic field generation
J/J = 110-7 ≈  0.2 pT
main solenoid
J
V
additional coils
-1,0652915
-1,065292
-1,0652925
voltage, V
-1,065293
1
201
401
601
801
1001
1201
J/J = 2.510-7 ≈  0.5 pT
-1,0652935
-1,065294
-1,0652945
-1,065295
-1,0652955
-1,065296
J/J =
2.510-7
≈  0.5 pT
time, min
44
The recent measurement
of EDM sensitivity
Direct measurement of sensitivity of EDM spectrometer with UCN
density 3-4 ucn/cm3 (MAM position) with electric field 10 kV/cm and
T(hold) = 65 s
-25
Dt=(16±14)*10 e*cm
-25
Db=(24±16)*10 e*cm
-25
D=-(4±6)*10 e*cm
400
-25
EDM [10 e*cm]
300
Dt
Db
D
200
100
0
-100
-200
-300
δDedm ~ 5∙10-25 e∙cm/day
-400
-500
0
5
10
15
Time of measurement [hours]
46
20
New result with HV
(+_)175kV/ 8.7cm = 20kV/cm
Corrected measurement of sensitivity of EDM spectrometer
with UCN density 3-4 ucn/cm3 (MAM position) with new
electric field 20 kV/cm and T(hold) = 65 s
ρucn at entrace ~ 3-4 ucn/cm3,
δDedm ~ 2.5∙10-25 e∙cm/day
Upper limit of sensitivity :
2.5∙10-26 e∙cm/100 days
Neutron EDM Experimental limit (e·cm)
History of nEDM measurements. Results and prospects
of PNPI-ILL-PTI collaboration
10
-20
10
-21
10
-22
10
-23
10
-24
10
-25
10
-26
10
-27
10
-28
Theoretical
Prediction:
- Electromagnetic
MIT-BNL
ORNL-Harvard
ORNL-ILL...
ILL-Sussex-RAL...
PNPI
- Weinberg Multi-Higgs
Present limit
Estimation of accuracy at ILL
!
- Minimal SUSY
Cosmology
- Left-Right Symm.
Estimations of accuracy at super UCN source
in Gatchina
!!
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020
Year
49
PNPI-ILL-PTI collaboration
Prospects to increase sensitivity of EDM measurements
Neutron EDM Experimental limit, e·cm
10
-25
Gatchina EDM spectrometer at ILL
double-chamber @
ILL MAM position
10
-26
Gatchina EDM spectrometer 1975
10
-27
10
-28
2011
2012
2013
2014
2015
Year
2016
2017
2018
PF2 position EDM
51
EDM spectrometer on the position EDM PF2
(legs of platform have to be cut ( 1.3 m))
upstairs
GAIN FACTOR IN UCN DENSITY is 3 - 4 times.
HV
analyzers
Test beam
Magnetic
shielding
detectors
Polarizer
Electronic equipment
UCN from turbine
52
EDM sensitivity at PF2 position “EDM”
2013 - 2014. New position at PF2 (EDM instead of
MAM) Factor in UCN density is about 3 – 4 times in
respect to MAM position.
ρucn at entrace ~ 20 ucn/cm3,
δDedm ~ 1∙10-25 e∙cm/day
Upper limit of sensitivity :
1∙10-26 e∙cm/100 days
PNPI-ILL-PTI collaboration
Prospects to increase sensitivity of EDM measurements
Neutron EDM Experimental limit, e·cm
10
10
-25
Gatchina EDM spectrometer at ILL
double-chamber @
ILL MAM position
double-chamber @
ILL EDM position
-26
Gatchina EDM spectrometer 1975
10
-27
10
-28
2011
2012
2013
2014
2015
Year
2016
2017
2018
EDM sensitivity at new position H172B,
UCN source with superfluid He at ILL.
2015. New position at H172B, UCN source
with superfluid He at ILL. Factor in UCN density
is about 10 times in respect to PF2 EDM
position.
ρucn at entrace ~ 200 ucn/cm3,
δDedm ~ 3.5∙10-26 e∙cm/day
Upper limit of sensitivity :
3.5∙10-27 e∙cm/100 days
PNPI-ILL-PTI collaboration
Prospects to increase sensitivity of EDM measurements
Neutron EDM Experimental limit, e·cm
10
10
-25
Gatchina EDM spectrometer at ILL
double-chamber @
ILL MAM position
double-chamber @
ILL EDM position
-26
double-chamber @
ILL UCN source
with superfluid He
Gatchina EDM spectrometer 1975
10
-27
10
-28
2011
2012
2013
2014
2015
Year
2016
2017
2018
PNPI-ILL-PTI collaboration
at Gatchina UCN supersource
at PNPI reactor WWR-M
future prospects
New facilities at PNPI,
UCN source with superfluid He.
2016. New facilities at PNPI, UCN source with
superfluid He. Factor in UCN density is about 60
times with respect to H172B ILL facility.
ρucn at entrace ~ 12000 ucn/cm3, δDedm ~ 5∙10-27 e∙cm/day
Upper limit of sensitivity : 5∙10-28 e∙cm/100 day
2017 -2018. New facilities at PNPI, UCN source with
superfluid He. Multichamber EDM spectrometer.
ρucn at entrace ~ 12000 ucn/cm3, δDedm ~ 3∙10-27 e∙cm/day
Upper limit of sensitivity : 3∙10-28 e∙cm/100 day
PNPI-ILL-PTI collaboration
Prospects to increase sensitivity of EDM measurements
Neutron EDM Experimental limit, e·cm
10
10
-25
Gatchina EDM spectrometer at ILL
double-chamber @
ILL MAM position
double-chamber @
ILL EDM position
-26
double-chamber @
ILL UCN source
with superfluid He
Gatchina EDM spectrometer 1975
10
-27
double-chamber @ PNPI super UCN source
10
-28
2011
2012
2013
2014
2015
Year
2016
2017
2018
PNPI-ILL-PTI collaboration
Prospects to increase sensitivity of EDM measurements
Neutron EDM Experimental limit, e·cm
10
10
-25
Gatchina EDM spectrometer at ILL
double-chamber @
ILL MAM position
double-chamber @
ILL EDM position
-26
double-chamber @
ILL UCN source
with superfluid He
Gatchina EDM spectrometer 1975
10
-27
double-chamber @ PNPI super UCN source
10
multi-chamber @ PNPI super UCN source
-28
2011
2012
2013
2014
2015
Year
2016
2017
2018
Project of ultracold and cold neutron source
with superfluid helium at WWR-M reactor
61
Thermal column of WWR-M reactor
Vertical cross section of WWR-M reactor.
1 – reactor core, 2 – reactor tank, 3 – concrete protection, 4
– chamber above the reactor, 5 – horizontal channel, 6 –
thermal column, 7 – vertical channel.
62
Cross section of WWR-M reactor
Idea
UCNs are generated in helium from cold neutrons of 9Ǻ wavelength (12 K energy). It is
correspond with phonon energy: cold neutron enegizes phonon, practically stops and
becomes an ultracold one. UCN can “lives” in superfluid helium for tens or hundreds of
seconds until a phonon be captured.
Cold neutrons (9Ǻ) penetrate through the wall of a trap, but ultracold neutrons (500Ǻ)
are reflected, that is why UCN can be accumulated up to the density defined by the time
of storage in the trap filled with superfluid helium.
Neutron scattering in liquid helium
I.Ya. Pomeranchuk “Selected works”
About neutron scattering with energy a few degree in fluid
Helium II
UCN =500 Å, T=10-3 K
The scattering of slow neutron in He-II is considered. It is
shown that the scattering is a negligible small at the
temperature below than temperature of critical point.
UCN source based on superfluid He-II
R. Golub, J.M. Pendlebury, Phys. Lett. A 62 (1977) 337
phonon
Ebeg=12 K  EUCN10-3 K
=9 Å
91
CN =9 Å, T=12 K
63
MCNP neutron flux calculation results and heat generation
in thermal column of WWR-M reactor at 15 MW
ucn=104 сm-3 (=10 s)
Ф=4.5∙1012 n/(сm2s)
Ф(=9 А)=3∙1010 n/(сm2sA)
QHe=6 W
He Т=1.2 К
19 W
LD2 Т=20 К
Al, QAl=13 W
C Т=300 К
Pb Т=300 К
LD2, QLD2+Al=100 W
C, QC=700 W
Pb, QPb=15 кW
Ф=1014 n/(cm2s)
Q=15 MW
64
Cryogenic scheme of UCN
source with superfluid He
UCN
CN
1 – He II cell; 2 – UCN neutron guide, 3 – CN neutron guide, 4 – He II supply pipe, 5 – lower bath @ 1.2 К, 6 – intermediate bath @ 1.2 К, 7 –
3Не filter, 8 – level sensor, 9 – upper bath @ 4.2 К, 10 – helium supply valve, 11 – level sensor, 12 – vacuum pipe (gravitation trap for UCN),
13 – vacuum pipe for lower bath, 14 – vacuum pipe for intermediate bath, 15 – main vacuum manifold, 16 – UCN neutron guide membrane,
17 – CN neutron guide membrane, 18 – thermal shield @ 20 К, 19 – vacuum jacket, 20 – UCN outer neutron guide, 21 – CN outer neutron
guide, 22 –helium supply at temperature of 4.2 К, 23 – pipe for helium vapour removal, 24 – helium supply for thermal shield 18, 25 –
65
helium removal from thermal shield 18, 26 – pumping of vacuum jacket.
Installation of UCN source on WWR-M reactor
а
b
c
d
а – Pb shielding mounting; b – graphite block mounting; c – mounting of cryostat, UCN superconductive
polarizer and UCN switchboard; d – mounting of 66
biological shielding.
Ultracold and cold neutron source at WWR-M reactor with
neutron guide halls
hall of thermal neutrons hall of ultracold
neutrons
hall of very cold
neutrons
67
hall of cold
neutrons
Demounting of old equipments
Demounting of old equipments is finished
General view with new equipment
70
Helium refrigerator
15 K, 3000 Watts
Helium liquefier
50 l/h
71
Gas system
72
Pumping system of helium
73
High pressure compressors
Water cooling system
Gas
Storage
System
Preparation of non-standard
equipment
Vacuum test of full-scale model of
UCN source
Cryogenic test of full-scale model
of UCN source
Manufacturing of cryostat
for superfluid helium at 1.2 K
Manufacturing of He heating system
Vacuum test of He heater
Manufacturing of He pumping tubes
Vacuum test of pumping tubes
Instead of summary
Neutron EDM Experimental limit, e·cm
10
-25
10
-26
10
-27
Gatchina EDM spectrometer at ILL
double-chamber @
ILL MAM position
double-chamber @
ILL EDM position
double-chamber @
ILL UCN source
with superfluid He
double-chamber @ PNPI super UCN source
10
multi-chamber @ PNPI super UCN source
-28
2011
2012
2013
2015
2014
Year
Gatchina EDM
spectrometer
1975
2016
2017
2018
Thank you for attention
Comparison of expected UCN density
with UCN density of present sources
UCN density, cm
-3
UCN density (сm-3)
Present project
104
ILL (turbine source)
10
10
5
10
4
10
3
10
2
10
1
10
0
10
-1
10
-2
10
-3
10
-4
10
-5
10
-6
10
-7
Gain factor
103
present PNPI project [17]
first test experiments
with superfluid He
SD2 pulse mode
LANL-PNPI [8]
ILL [4]
ILL [12]
PNPI
ILL
SRIAR PNPI
PNPI IAE
TUM
PNPI
IAE
projects
[15-16]
ILL[13]
PNPI [3]
PNPI
PNPI [6]
PNPI [5]
first test
experiment
with SD2
SD2 Mainz [9]
SD2 reactor
test experiment
PSI-PNPI [10]
project
SD2 in pulse mode
JINR
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
87
years