Status of the q n Experiment in Mainz C. Siemensen Institute of - - PowerPoint PPT Presentation
Status of the q n Experiment in Mainz C. Siemensen Institute of Nuclear Chemistry Johannes Gutenberg-University of Mainz International UCN Workshop Mainz, Germany, April 11 th -15 th, 2016 April 13th, 2016 C. Siemensen (Kernchemie) Status of
Institute of Nuclear Chemistry Johannes Gutenberg-University of Mainz International UCN Workshop Mainz, Germany, April 11 th -15 th, 2016
April 13th, 2016
Status of the qn Experiment in Mainz April 13th, 2016 1 / 22
ε /qn in the Past
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ε /qn in the Past
2
Apparatus
3
Fomblin as Horizontal Mirror
4
Charge Measurement
5
Summary and Outlook
Status of the qn Experiment in Mainz April 13th, 2016 2 / 22
ε /qn in the Past
Charge of the free neutron using UCN "former experiment" Scattering myon neutrinos - electrons Neutrinos of supernova SN1987A Neutral matter ~HV (Borisov) Charge of the free neutron using CN (Baumann)
1
1https://www.cfa.harvard.edu/sins/datajan2007/sn1987a_wide.tif
Status of the qn Experiment in Mainz April 13th, 2016 3 / 22
Apparatus
1
ε /qn in the Past
2
Apparatus
3
Fomblin as Horizontal Mirror
4
Charge Measurement
5
Summary and Outlook
Status of the qn Experiment in Mainz April 13th, 2016 4 / 22
Apparatus
UCN beam
cylindrical mirror input grating unpertubed beam deflected beam force detector exit grating +
Status of the qn Experiment in Mainz April 13th, 2016 5 / 22
Apparatus
UCN beam
cylindrical mirror input grating unpertubed beam deflected beam force detector exit grating +
gratings electrodes cylindrical mirror former experiment
Status of the qn Experiment in Mainz April 13th, 2016 5 / 22
Apparatus
cylindrical mirror electrode Fomblin basin exit gratings input grating
Status of the qn Experiment in Mainz April 13th, 2016 6 / 22
Apparatus
former experiment* new geometry
entrance guide
detector & grating
0.001 0.01 0.1 1 5 10 15 20 25 30 35 40 45 UCN number of hor. reflections former exp. 1m former exp.* 1.5m new geometry 1.5m
Status of the qn Experiment in Mainz April 13th, 2016 7 / 22
Apparatus
former experiment* new geometry
entrance guide
detector & grating
0.001 0.01 0.1 1 5 10 15 20 25 30 35 40 45 UCN number of hor. reflections former exp. 1m former exp.* 1.5m new geometry 1.5m
Mean reflections: former exp. 1.0m : ¯ R ≈ 21.7 former exp.* 1.5m : ¯ R ≈ 31.9 new geometry 1.5m : ¯ R ≈ 1.7
Status of the qn Experiment in Mainz April 13th, 2016 7 / 22
Apparatus
gratings: ∆α ≤ 90µrad mirror:∆α ≤ 350µrad
Status of the qn Experiment in Mainz April 13th, 2016 8 / 22
Apparatus
Without conditioning and cleanroom conditions: Emax ≈ 1.6 MV
m were
possible
Status of the qn Experiment in Mainz April 13th, 2016 9 / 22
Fomblin as Horizontal Mirror
1
ε /qn in the Past
2
Apparatus
3
Fomblin as Horizontal Mirror
4
Charge Measurement
5
Summary and Outlook
Status of the qn Experiment in Mainz April 13th, 2016 10 / 22
Fomblin as Horizontal Mirror
pros high viscosity: 1508cSt2 dielectric constant independent from electric field (up to 640kV/m) surface roughness ≈ 5.24Å cons no solubility in most detergents dissolved air bubbles pop under vacuum dielectric (moves if ∇ E = 0) cracks when freezed out
2Solvay Solexis. Perfluorpolyether - Fomblin Y, M und Z-Öle + Fomblin Fette. 2004
Status of the qn Experiment in Mainz April 13th, 2016 11 / 22
Fomblin as Horizontal Mirror
0.02 0.04 0.06
residuals Δε T / °C 20kV/m 200kV/m 404kV/m 579kV/m 640kV/m
1 e− 4 1 e− 3 1 e− 2 1 e− 1 1 e0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 R/Rf q2[1/Å ]
2ambient temperature Fit 0°C Fit − 30°C Fit − 55°C Fit
Status of the qn Experiment in Mainz April 13th, 2016 12 / 22
Fomblin as Horizontal Mirror
new geometry ⇒ reduction of the number of horizontal reflections prolongated flight path ⇒ doubling of the sensitivity automatic adjustment system ⇒ smaller slit widths improved electrode system ⇒ higher HV-stability liquid Fomblin mirror ⇒ no adjustment required
Status of the qn Experiment in Mainz April 13th, 2016 13 / 22
Fomblin as Horizontal Mirror
new geometry ⇒ reduction of the number of horizontal reflections prolongated flight path ⇒ doubling of the sensitivity automatic adjustment system ⇒ smaller slit widths improved electrode system ⇒ higher HV-stability liquid Fomblin mirror ⇒ no adjustment required
⇒ δqn ≈ 1.3· 10−21 e √ d
level of Baumann obtainable within one day
Status of the qn Experiment in Mainz April 13th, 2016 13 / 22
Charge Measurement
1
ε /qn in the Past
2
Apparatus
3
Fomblin as Horizontal Mirror
4
Charge Measurement
5
Summary and Outlook
Status of the qn Experiment in Mainz April 13th, 2016 14 / 22
Charge Measurement
Status of the qn Experiment in Mainz April 13th, 2016 15 / 22
Charge Measurement
Beam time 3.11. - 1.12.2014 at UCN, ILL: Parameters: Value: mean flight path t in E-field E
(0.70± 0.20)s
neutron fluxes n1 ≈ 19 1
s n2 ≈ 53 1 s n3 ≈ 57 1 s n4 ≈ 40 1 s
electric field ∆E 1.2MV
m
gratings 0.4mm slit, 0.7mm spacing slopes
∂xn1 = −6273 1
s·m ∂xn2 = −37173 1 s·m
∂xn3 = 45820 1
s·m ∂xn4 = 44563 1 s·m
τ = 3.44· 105 s (approx 4 days)
statistical sensitivity 2.4· 10−20
e
√ d (3.8 times larger)
Status of the qn Experiment in Mainz April 13th, 2016 16 / 22
Charge Measurement
20 30 40 50 60 70 80 6 7 8 9 10 11 12 13 14 15 count rate / 1/s x / mm APO APU Det 1 Det 2 Det 3 Det 4
1 2 3 4
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Charge Measurement
20 40 60 80 100 120 140
50 100 150 200 frequency Δx / µm Det 1 Det 2 Det 3 Det 4
∆x1 = (7.19± 2.58)· 10−6 m ∆x2 = (5.34± 0.69)· 10−6 m ∆x3 = (3.35± 0.60)· 10−6 m ∆x4 = (4.01± 0.52)· 10−6 m
10 20 30 40 50 60 70 80 90
1e-18 2e-18 3e-18 frequency charge qn/e
qn =(−1.82± 0.24stat. ± 0.09∂xn ...
...± 0.02E ± 0.78t)· 10−19e
Status of the qn Experiment in Mainz April 13th, 2016 18 / 22
Charge Measurement
Possible systematic effects: motion of the HV-switch breakdown of the fields
Fomblin in E-field
Status of the qn Experiment in Mainz April 13th, 2016 19 / 22
Charge Measurement
Possible systematic effects: motion of the HV-switch breakdown of the fields
Fomblin in E−field ? ⇒ distortion by
−|U−| ≈ 5.2kV
Status of the qn Experiment in Mainz April 13th, 2016 19 / 22
Charge Measurement
Possible systematic effects: motion of the HV-switch breakdown of the fields
Fomblin in E−field ? ⇒ distortion by
−|U−| ≈ 5.2kV
considering both effects: qn =(−0.32± 1.22stat. ± 0.39∂xn ±...
...± 0.10E ± 0.14t ± 1.29xkorr.)· 10−20e ⇒ qn ≤ 1.8· 10−20 e
Status of the qn Experiment in Mainz April 13th, 2016 19 / 22
Charge Measurement
0.1 0.2 0.3 0.4 0.5
2 4 surface distortion / µm x / cm symmetric asymmetric 2,5kV asymmetric 5,0kV asymmetric 10kV
Basin Shielding Electrodes
δeff =
1 xr − xl
xr
dSF(x) dx ˜ Ω(x)dx δeff(symm.) = −0.04µrad δeff(asymm.2.5kV) = −0.37µrad δeff(asymm.5.0kV) = −0.73µrad δeff(asymm.10kV) = −1.28µrad
∆F = ∆E · qn = g mn sinδα ⇒ δα ≈ 1.5µrad ⇒ ∆U± ≈ 5.2kV
Status of the qn Experiment in Mainz April 13th, 2016 20 / 22
Summary and Outlook
1
ε /qn in the Past
2
Apparatus
3
Fomblin as Horizontal Mirror
4
Charge Measurement
5
Summary and Outlook
Status of the qn Experiment in Mainz April 13th, 2016 21 / 22
Summary and Outlook
charge of the free neutron linked to the problem of ECQ drafting a new charge experiment (dedicated geometry, new HV-system, adjustment, . . . ) first charge experiment since 1987: 2.4· 10−20
e
√ d
understanding of systematic effects: replace horizontal mirror/ extended screening, assure electric potential of the electrodes potentially δqn ≈ 1.3· 10−21
e
√ d in the near future
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