Principle with UCNs A.F. Frank frank@nf.jinr.ru International - - PowerPoint PPT Presentation

1

A.F. Frank

frank@nf.jinr.ru

Tests of the Weak Equivalence Principle with UCNs

International Workshop "Probing Fundamental Symmetries and Interactions with UCN". Mainz, April 11th-15th, 2016

2

• Neutrons and gravity (short review)
• Moving grating and the experiment of 2006
• Moving grating, flux modulation and the

experiment of 2010-2012.

• Moving grating and Fountain experiment
• Road map to the new gravity experiment

Outline

• A. Frank. UCN workshop, Mainz, 2016

3

1. g =935  70cm/sec2 2. g(002)=973.1  7.4cm/sec2 g(100)=975.1  3.1cm/sec2 gloc = 979.74cm/sec2

J.W.Dabbs,J.A.Harvey, D.Pava and H.Horstmann, 1965

• A. Frank. UCN workshop, Mainz, 13 April, 2016

4

L.Koester, 1976

2 loc i g n

g m m m g  

V.F.Sears,1982

1- = 310-4

2

2

g i n

m g h m b   

2

2

eff

mgh U b m   

• J. Schmiedmayer, NIM A 284, (1989) 59

1-  = 1.00011  0.00017

• A. Frank. UCN workshop, Mainz, 13 April, 2016

5

Koester’s experiment and the problem of n-e scattering

It is not evident that bne is known with such precision even now When the value of bcoh extracts from the total cross section data it is necessary to take into account the n-e scattering. For the case of Pb and Bi correspondent corrections are of the order 1%. Consequently, if one aim to reach 10-4 in precision of bcoh the amplitude of n-e scattering must be known with precision of 1%.

Schmiedmayer used statistically inconsistent data for n-e scattering

• A. Frank. UCN workshop, Mainz, 13 April, 2016

6 2

2

eff

mgH U b m   

What is a precision of the above equation for the effective potential U?

Koester’s experiment and effective potential

Theory: (estimation for lead at Vn  400 m/sec) – corrections of the order of 510-5

There are no any experiments for the test of theory with precision better than some percent

V.F.Sears (1982); M. Warner, J.E Gubernatis. (1985) Lax, 1951

• A. Frank. UCN workshop, Mainz, 13 April, 2016

7

Neutron Interferometric Experiments (COW – type experiment)

R.Colella, A,W.Overhauser and S.A. Werner (COW), 1975 K.S.Litrell, B.E.Allman and S.A.Werner, 1997

The experimentally obtained values for the gravitationally induced phase factor were lower than the theoretically expected value by 1.5% for the skew-symmetric interferometer data and 0.8% for the symmetric interferometer data in measurements with relative uncertainties

• f 0.12% and 0.11%, respectively.
• A. Frank. UCN workshop, Mainz, 13 April, 2016

8

1- = (1±9)10-3

• A. Frank. UCN workshop, Mainz, 13 April, 2016

9

H

E0  E

E

 

H

The idea was to compare the change of energy mgH with energy ħΩ transferred to neutron by a moving grating

Frank A.I., Masalovich S.V., Nosov V.G. (ISINN-12). E3-2004-169, 215, Dubna, (2004) i n

ΔΩ m g = ΔH

Test of the weak equivalence principle for neutrons (2006)

• A. Frank.UCN workshop, Mainz, 13 April, 2016

10

E

ΔE = Ω

E = ω

1

• 1

2

• 2

Moving diffraction grating as a nonstationary device

V

z y

e− ikz z

2 V L   

V – grating velocity L – period of grating

• A. Frank.UCN workshop, Mainz, 13 April, 2016

 

j

j   

1 2

1

j

k j k          

j j j j j

(z,y,t) a exp[i( t ] q k z y )      

11

Moving (rotating) diffraction grating as a nonstationary device

UCN

Monochromator

Phase π -grating

where N is number of groves

N = 75398

n L d

      d ) n ( k 1

E

1

• 1

ΔE = Ω ΔE = Ω

• A. Frank.UCN workshop, Mainz, 13 April, 2016

12

Energy of the state

  2

, 1 2 2 , 1

b m 2 U    

1 2 1 Substrate

50 100150 200250 300 350400 450500 0,0 0,2 0,4 0,6 0,8 1,0 Transmission Energy (neV)

Fabry-Perot interferometers (Neutron Interference filters) as a spectrometric device

• A. Frank.UCN workshop, Mainz, 13 April, 2016

13

Experimental results

40 50 60 70 80 90 100 110 10 15 20 25 30 35

Fitted Hmax Rotation frequency (rot/sec)

h0= c +B*f

3 n loc i n

m g 1 (1.8 2.1) 10 m g



   

Bexp= 0.3037 ± 0.00065 Bth = 0.304203

A.I. Frank, P. Geltenbort, M. Jentschel,et al. JETP Letters, 86, 225 (2007)

3 loc n

g 1 (1.8 2.1) 10 g



   

2

th loc

N B mg  

10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 1,0 1,5 2,0 2,5 3,0 3,5 4,0

Count rate (c/sec) Distance betwee the filter (cm) f=45Hz f=55Hz f = 64 Hz f =75Hz f =95Hz f =105Hz

• A. Frank. UCN workshop, Mainz, 13 April, 2016

14

Flux modulation TOF base E1 Count-rate oscillations on a detector E2 E3 E1>E2>E3

φ = 2πft

Experiment of 2010-2012.

Comparing the energy mgH with energy ħΩ as before Combination of Neutron Interference Filters with peculiar TOF spectrometry

Flux modulation

• A. Frank.UCN workshop, Mainz, 13 April, 2016

15

Experiment of 2010-2012. Part I Calibration

Monochromator

Detector

Calibration Variation of the monochromator vertical position leads to changing of the UCN energy, time of flight and total phase of the count rate oscillation

15 20 25 30 35 40 45 70 72 74 76 78 80

Total phase of the count rate modulation

Positon of carriage (mm)

Modulation frequency 75Hz

φ= f (Ea− mggn H)

• A. Frank. UCN workshop, Mainz, 13 April, 2016

16

Detector Monochromator grating Detector Monochromator grating

The count rate oscillation phase of the UCN which energy shifted by rotating grating must be compared with the calibration curve Unfortunately -1 order of diffraction is accompanied by the +1 and diffraction.

• rders of higher orders

15 20 25 30 35 40 45 70 72 74 76 78 80

Total phase of the count rate modulation Position of the carriage (mm)

 

mon

φ= f E Ω 

 

mon

φ= f E

 



mon

φ= f E Ω

Experiment of 2010-2012. Part II (idea)

• A. Frank.UCN workshop, Mainz, 13 April, 2016

17

Using special 9-layers filter with wide transmission band we selected the line of the -1 diffraction order

Detector Monochromator grating Wide- analyzer

90 100 110 120 130 0,0 0,2 0,4 0,6 0,8 1,0

Transmittivity E, (nev) 12 neV

E

ΔE = Ω E = ω

1

• 1

2

• 2

E

ΔE = Ω E = ω

1

• 1

2

• 2

Counts E , neV

• A. Frank.UCN workshop, Mainz, 13 April, 2016

18

Detector Monochromator grating Wide analyzer

The count rate oscillation phase of the UCN which energy shifted by the grating rotating with different frequency must be compared with the calibration curv

15 20 25 30 35 40 45 70 72 74 76 78 80

Total phase of the count rate modulation Position of the carriage (mm)

 

1



mon

φ= f E Ω

 

2



mon

φ= f E Ω

Experiment 2010-2012. Part II (idea)

ΔH

i n

ΔΩ m g = ΔH

• A. Frank.UCN workshop, Mainz, 13 April, 2016

19

Experiment of 2010-2012.

• A. Frank.UCN workshop, Mainz, 13 April, 2016

20

Experiment of 2010-2012. Found

problem

15 20 25 30 35 40 45 70 72 74 76 78 80

Total phase of the count rate modulation Position of the carriage (mm)

 

mon

φ= f E Ω 

 



mon

φ= f E Ω

The role of the even diffraction orders was underestimated

• A. Frank. UCN workshop, Mainz, 13 April, 2016

21

Experiment of 2010-2012. Found

problem

15 20 25 30 35 40 45 70 72 74 76 78 80

Total phase of the count rate modulation Position of the carriage (mm)

 

mon

φ= f E Ω 

 



mon

φ= f E Ω

The role of the even diffraction orders was underestimated

• A. Frank. UCN workshop, Mainz, 13 April, 2016

a b

 x' x'

22

The present status of experiment (2014)

1. The full scale test measurements with new spectrometer was performed.

• 2. The rate of the collection of statistical accuracy, was obtained as 5×10-3

per day. That is enough to collect statistical accuracy of the order of 5×10-4 during two cycle of statistic collection at PF2 source.

• 3. It was realized that it is rather difficult to exclude the systematic effect

due to admixture of the neighbor (even) diffraction orders to the spectrum of minus first order.

• 4. The parasitic high energy line which may disturbs the phase of the

count rate oscillation was found

114 nev 255 neV

• A. Frank.UCN workshop, Mainz, 13 April, 2016

23

• A. Frank. UCN workshop, Mainz, 13 April, 2016

Resent results of the g-measure experiments

• 1. Victor-O. de Haan, J.Plomp, Ad A. van Well, M. Theo Rekveldt et al.

“Measurement of gravitation-induced quantum interference for neutrons in a spin-echo spectrometer”. Phys.Rev.A 89, 063611 (2014)

“The result for the gravitation induced phase shift agrees within approximately 0.1% with the theoretically expected result, while the overall measurement accuracy is 0.25%.”

• 2. G. Cronenberg, H. Filter, M.Thalhammer, T. Jenke and H. Abele. “A Gravity of Earth

measurement with a qBOUNCE experiment”. arXiv:1512.09134v1 [hep-ex]. 30 Dec 2015

“The measurements demonstrate that Newton’s Inverse Square Law of Gravity is understood at micron distances at an energy level of 10 -14 eV with Δg/g = 4×10-3.”

24

TOF Fourier mode of the UCN spectrometer (November 2014)

24

• A. Frank.UCN workshop, Mainz, 13 April, 2016

G.V. Kulin, A.I. Frank, S.V. Goryunov et al., NIM A, 869 (2016) 67

25

It is possible to measure wide spectrum

• f diffracted UCNs

25

20 40 60 80 100 120 140 160 180 200 1 2 3 4 5

Int (arb.units) Energy (neV)

• 2

+2

• 1

+1

G.V. Kulin, A.I. Frank, S.V. Goryunov, et al., Phys. Rev.A 93,(2016) 033606

• V. A. Bushuev, A. I. Frank, and G. V. Kulin. JETP, 122 (2016) 32
• A. Frank.UCN workshop, Mainz, 13 April, 2016
• G. Kulin. Talk today later

4800rpm

26

Possibility of future application

• A. Frank.UCN workshop, Mainz, 13 April, 2016

h One equation with three unknowns

g E h E 2 1 m t 1 1 m g         

27

• A. Frank.UCN workshop, Mainz, 13 April, 2016

h

1 1

2( ) 1 m t 1 1 m 1 m t E h E 2 1 1 m 2( ) 1 m t 1 g g g E h E E g g g h 1 m E



                                             

Tree equations with three unknowns

Possibility of future application

28

A set of equations with three unknowns

M.A. Zakharov, G.V. Kulin, A.I. Frank, D.V. Kustov, S.V. Goryunov. arXiv:1602.00941v1 [nucl-ex]

• A. Frank.UCN workshop, Mainz, 13 April, 2016

k j,k k

2( j ) 1 m t 1 1 m E j E g g h             

h

Possibility of future application

29

Detector

• 3. Because the energy of the lines is unknown, it was proposed to vary height of detector

for calculation of g.

Yu.N.Pokotilovsky, 1994

Neutron fountain for the measure of gn by TOF method

• 1. Interference filter with number of lines
• 2. Correlation time of flight spectroscopy

with pseudo-random chopper

• A. Frank.UCN workshop, Mainz, 13 April, 2016

30

Detector

Neutron fountain for the measure of gn by TOF method

We propose to use the idea of Yu. P. with one but important modification

• 1. Use interference filter with single line

and 2 add a moving grating to split spectrum

• 3. TOF Fourier or pseudo-random

chopper

• A. Frank.UCN workshop, Mainz, 13 April, 2016

31

2 4 6 8 10 12 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3

Time (s) Modulation frequency (MHz)

H

Detector Monochromator Quantum splitter- moving grating Fourier chopper

H

Detector Monochromator Quantum splitter- moving grating Fourier chopper

Neutron Fountain with energy splitting and TOF Fourier spectrometry

Precision in the TOF measurement 10 μs Corresponds to the precision g/g  10 - 5

50 100 150 200 0,00 0,05 0,10 0,15 0,20 0,25 0,30

100 Hz Intencity Energy (nev) B

E    E   

• A. Frank.UCN workshop, Mainz, 13 April, 2016

32

Neutron Fountain with energy splitting and TOF Fourier spectrometry

Advantages

• 1. Only time-of-flight values of neutrons from different

lines of the spectrum must be measured. Neither the initial neutron energy, nor the geometry parameters of the installation are required to be known.

• 2. Fourier time of flight approach is not sensitive to the

fluctuations of intensity, background and detector efficiency Disadvantage Small solid angle ( 0.01*2) of the neutron flux is accepted.

• A. Frank. UCN workshop, Mainz, 13 April, 2016

33

Way to the gravity experiment with the precision g/g  10 -5

1. a)Test of the grating with increased intensities of the second orders b) Experimental verification of the possibility to reach accuracy in the time measurement of the order of 10µs using TOF Fourier spectrometry.

Next experimental cycle using exists spectrometer with small modification 2.Test experiment – g measure using moving grating and new Fourier spectrometer at the level g/g  10 -3

• 3. Project of the Fountain experiment
• A. Frank.UCN workshop, Mainz, 13 April, 2016

34

• P. Geltenbort, P. Høghøj, M. Jentschel

S.V.Goryunov, G.V.Kulin, D. Kustov, M Zakharov. S.V.Masalovich, S.N.Strepetov

• V. A. Bushuev

Thank you for your attention!

34

• A. Frank.UCN workshop, Mainz, 13 April, 2016
• B. Lauss, P. Schmidt-Wellenburg

35 35

100 200 300 20 40 60 80 100 120 140

Counts Chanels

• A. Frank.UCN workshop, Mainz, 2016