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