Stahl-electronics HF-D 200, HF-D 425, HF-D 600 User Manual

HF-D series

RF drive amplifiers for Ion Traps

HFD_Drives_Manual_2_1.doc

28 - April - 2013

User Manual

Rev. 2.1

Models HF-D 200, HF-D 425, HF-D 600

Main Features:

● RF drive amplifier for ion traps

● up to 600Vppinto 100pF load

● f = 360kHz to 1.5MHz, model dependent

● non resonant broadband design

● precision voltage stabilisation (device option)

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HF-D User Manual, Rev 2.1

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TABLE OF CONTENTS

1. Safety Hints ………………………………….…………………………………… 3

2. General Information and Overview………………….………………………….. 4

2.1 Purpose and Description of the Device…………………………….. 4

2.2 Functional Principle and Block Diagram…………………………. 4

3. Installation ……………………………………………………………………..… 5

3.1. Mechanical and Electrical Installation……………………………… 5

4. Operation and Control Elements ……………………………………………….. 6

4.1 Elements on the Front Plate………………………………………… 6

4.2 Elements on Rear Side……………………………………………… 8

4.3 Output Characteristics……………………………………………… 9

4.3.1 Stability and Fast Turn-On/Off Feature……………… 9

4.3.2 Output Harmonics…………………………………… 10

4.3.3 Dipole Excitation…………………………………….. 10

4.4 Precision Output Amplitude Regulation …………………………… 11

5. Maintenance………………………………………….…………………………. 12

6. Specifications……………………………………………………………………. 13

Declaration of Conformity ………………………………………………………… 15

HF-D User Manual, Rev 2.1

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1. Safety Hints

Read all installation, operation, and safety
instructions

Prior to operation, thoroughly review all safety,
installation, and operating instructions accompanying

this equipment.
Rear side switch turns device completely
off

If the device is not in use for a longer time, it is

recommended to turn the mains switch at rear side off.
This equipment must be connected to an
earth safety ground

This product is grounded through the grounding

conductor of the power cord. To avoid electrical

hazard, the grounding conductor must be connected to

protective earth ground.
Do not modify the unit Do not make electrical or mechanical modifications to

this unit.
Change cabling only when device is off Changing the cabling, when voltages are present at the

outputs can lead to formation of harmful sparks.
Do not operate in wet/damp conditions To avoid electric shock hazard, do not operate this

product in wet or damp conditions. Protect the device

from humidity and direct water contact.
Beware of external magnetic fields External magnetic fields can impair, damage or even

destroy this device. A maximum external field strength

of no more than B = 5mT is admissible. Having placed

the device at any time into an external magnetic of

bigger B = 5mT (regardless if power was turned on or

off) can lead to severe overheating of the device and

severely increased hazard of fire.
Service is to be performed by qualified
service persons only

All servicing on this equipment must be carried out by

factory-qualified service personnel only.
Do not block chassis ventilation openings Slots and openings in the chassis are provided for

ventilation purposes to prevent overheating of the

equipment and must not be restricted.

All case vents should continuously be cleared (fan

inlets at rear side, air outlets on top side), in order to

prevent overheating. If mounted in a rack, allow 4cm

clearance at the top cover with respect to the next

device above.
Operate carefully with respect to risk of
electrical shock

This device can produce high voltages at its output

lines, which are harmful in case of direct touch with the

human body. Care must be taken to avoid unintentional

touching of any output line or connection to any device

which might be endangered by high voltages.
Routinely cleaning from dust After long operation, or operation in a dusty

environment it is strongly recommended to have the

internal parts of the device cleaned by the

manufacturer, or an appropriately qualified workshop

in order to reduce the hazard of overheating.
No outdoor operation Outdoor operation of the device is not admissible.

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2. General Information and Overview

2.1 Purpose and Description of the Device

Purpose of the RF drives HF-D 200, HF-D 425 and HF-D 600 is the supply of AC voltages to Paul Ion
Traps and other Quadrupole-type electrode setups for ion storage and manipulation. Unlike standard RF
(radio- frequency) power amplifiers, the device is capable to handle capacitive loads, which are related to
vacuum setups for ion trapping and storage. The devices feature a fast-turn-on/off capability to capture
ions in flight. Other common RF drives usually require a certain amount of time to build up the nominal
output voltage since they are based on a resonant voltage transformation. In contrast the RF drive HF-D
series consists of broadband devices which allow for instant turn-on and fast turn-off of the AC output
voltage. For example, the HF-D 200A is designed to deliver up to 200VppAC voltage of 600kHz to

1.5MHz frequency into a 100pF load on each output, the HF-D 600 is designed to deliver up to 600V

pp

AC voltage of 300kHz to 600kHz frequency into a 100pF load on each output. The devices are housed in a
standard 19-inch rack-mount case.

Fig. 2.1: RF drive HF-D 200A, trapping field generator in 19”-case.

2.2 Functional Principle and Block Diagram

The following picture displays a block diagram of the internal structure, illustrating the functional
principle. The voltage at the main signal input controls a fast electronic switch, which switches between
the high and low level of the external supply voltage, creating a rectangular shaped high voltage signal.
The rate at which this switching happens is defined by the frequency at the signal input (for instance
600kHz). A subsequent sine wave filter removes the higher harmonics, thus creating a sine-shaped high
voltage waveform. The DC level of the externally supplied DC voltage at rear input defines the devices
output AC level, since both voltages are in linear relation. This also means that output regulation of the
device AC level is done by choosing the appropriate input high voltage DC supply level.

Fig. 2.2: Block diagram of internal circuitry

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As shown in the block diagram, an additional DC offset may be added to the output sine wave. This
voltage is applied at the rear side and adds linearly to the output sine, therefore shifting its DC level.

Furthermore an excitation signal may be applied, which also adds to the trapping field. This add-on signal
is split in to an in-phase and 180°-shifted part. Both parts are added to the trapping field, and the
sum/difference is subsequently available on the two BNC output plugs (denominated as outputs A and B)
on the rear side. This feature is specially suited for creating an AC dipolar field in the order of a few
Millivolts to a few Volts inside an attached ion trap. Note, that the dipolar excitation signal, being applied
on the front side of the device is attenuated or amplified to a certain degree. Figure 4.8 shows the
frequency response of this dipolar signal in terms of the voltage difference at the outputs A-B versus
frequency, at a given input excitation amplitude.

3. Installation

3.1 Mechanical and Electrical Installation

Positioning: Provide sufficient air cooling of the device and locate in normal horizontal position to allow
for defined air convection. Rack mounting into a standard 19” rack is as well possible as resting the device
on a table. If mounted in a rack, allow 4cm clearance at the top cover with respect to the next device
above. All case vents must permanently be cleared (inlet at rear side and air outlet at top side), in order to
prevent overheating. Please note that the device may experience serious damage in case

sufficient air ventilation is not given.

Fig.3.1 Air vents (marked blue) must all be kept clear to ensure sufficient ventilation. Under no circumstances the
vent slits must be blocked, since they are vital for device operation in order to prevent overheating.

Beware of external magnetic fields:
Strong external magnetic fields can impair, damage or even destroy this device (e.g. proximity to a
superconducting magnet). A maximum external field strength of no more than B = 5mT is admissible. Not
observing this important condition can lead to severe overheating of the device and increases the hazard of
fire.

Connecting to mains power:
Connect the device to the mains power supply by using an appropriate power cord, being properly wired
and providing a grounded outlet. The power cord must be suited with respect to possible load currents and
should be rated to 2A current.

Cabling of voltage outputs:
Always provide appropriate and safe cabling when connecting the device to other devices or
vacuum/experimental setups. Cabling is preferred using a high voltage low-capacitance cable with proper
shielding. A suitable choice of cable type is e.g. a RG62 type, which has a small parasitic capacitance of
approx. 48pF/m, half the value of standard RG58 BNC cable. The smaller parasitic capacitance allows a
higher degree of freedom since cable capacitance significantly contributes to the overall (terminal)
capacitance, which must not exceed 100pF (each output) to meet the device specifications.