testing the penning trap (operated as a paul trap)
DESCRIPTION
Testing the Penning trap (operated as a Paul trap). endcap. ring. endcap. DC. trap potential. +. -. RF. ~. bias potential. +. DC. -. ground. Trap T est - The Experimental Setup. -3 k V. +250 V. 100 e V. Faraday cup. Einzel lens. Ar + source. Trap testing: - PowerPoint PPT PresentationTRANSCRIPT
Testing the Penning trap
(operated as a Paul trap)
Zoran Anđelković
Trap Trap TTest - est - The Experimental SetupThe Experimental Setup
+250 V 100 eV
pA
Faraday cup
Einzel lens
Ar+ source
endcap ring endcap
DC-+
ground
RF
~
DC
+
-
trap potential
bias potential
Capturing and
storing
Detection
-3 kV
Trap testing: Vary the trapping time Vary the trapping
voltages Monitor the ion count
Zoran Anđelković
Overview of the SystemOverview of the System
Trap and optics voltage supplies
Measuring cycle
Channeltron
Zoran Anđelković
First ResultsFirst Results
• Dependence on the trap voltage as expected
• Strong dependence on RF amplitude
0 10 20 30 40 500
20
40
60
80
100
120
140
160
180
Co
un
t
Capture Voltage [V]
Bias Voltage: 37 VTrapping time: 2 s
Paul trap stability diagram
qz ~ RF amplitude
az ~
Vd
c
De
tect
ed
nu
mb
er
of
ion
s
Trap voltage [V]
Bias Voltage: 37 VTrapping time 2 sRF apmpitude 300 V (1 MHz)
Zoran Anđelković
Trap Test - ResultsTrap Test - Results
• Exponential decay expected• Storage time vs. ion count – “dead time” problems• Good results at low ion counts
0 2 4 6 8 10 120
50
100
150
200
250
300
Co
un
t
Trapping time [s]
10 V DC capture71 V biasD
ete
cte
d n
um
be
r o
f io
ns
Trap voltage: 10 VBias voltage 71 VRF apmpitude 300 V (1 MHz)
-1 0 1 2 3 4 5 6 7 8
0
40
80
120
160
200
240
280
320
pressure: 8,7 * 10-8 mbarDC capture: 5 VRF amplitude: 300 V
Equation: y = A1*exp(-x/t
1) + y
0
2/DoF = 2.40751
R2 = 0.99624 y
0-152.77896 ±39.54893
A1
451.80571 ±38.26513
t1
7.05356 ±1.04705
raw data corrected
Ion
co
un
tTrapping time [s]
Laser system & Locking
Zoran Anđelković
Laser - Laser - An Overview of an ECDLAn Overview of an ECDL
External Littrow resonator
Single mode operation
Simple and fast constr-uction
Cheap components
Zoran Anđelković
Laser Laser Linewidth MeasurementsLinewidth Measurements
• Laser and FPI linewidth convolution• Sutalble for most applications
0,00 0,01 0,02 0,03 0,04-0,005
0,000
0,005
0,010
0,015
0,020
0,025
0,030
0,035
0,033 0,034 0,035 0,036 0,037
0,00
0,01
0,02
0,03
0,04
inte
nsi
ty [
arb
. u
nits
]
frequency [arb. units]
FWHM= 18 MHz
in
ten
sity
[a
rb.
un
its]
frequency [arb. units]
FSR = 2 GHz
Zoran Anđelković
Laser Laser Locking and StabilizationLocking and Stabilization
Faraday rotatorLASER toexperiment
Variableattenuator
Reference FPI
DifferentialamplifierSimulated
by reference electronics
PD 1
PD 2
Zoran Anđelković
• Successful locking for more than 30 min.
• Up to 2 GHz scanning range
• Scannable
Laser Setup OverviewLaser Setup Overview
Zoran Anđelković
Locking StabilityLocking Stability
0 400 800 1200 1600 2000
-3
-2
-1
0
1
2
3
err
or
sig
na
l [V
]
time [s]
-10 0 10 20 30 40 50 60 70 80-1,2
-0,8
-0,4
0,0
0,4
0,8
time [s]
err
or
sig
na
l [V
]
• Laser in lock – error signal drifts around the zero
• Out of lock – error signal drifts randomly
Zoran Anđelković
Spectroscopy TestSpectroscopy Test
The assembled laser system
Thermal Li atomsource
Results:
• fluorescence at 671 nm• two hyperfine components
Zoran Anđelković
Improvement and OutlookImprovement and Outlook
• Penning trap under construction at GSI• Operation of the laser system with different
wavelengths (laser diodes)• First SPECTRAP experiments expected during 2009
Further improvement:
Implementation:
• Locking of the FPI to a He-Ne• Broader (mode-hop free) scanning rang• Test – spectroscopy inside the trap