摘要:
An MS/MS-time-of-flight mass-spectrometer for colliding ions with the molecules or atoms of some collision gas. In order to assign the fragment ions to their respective parent ions, some ion selecting mechanism such as an ion gate must be used to preselect one specific mass of the primary ion spectrum. Usually the combination of both elements, a collision cell and an ion selector will need so much space that the size of the mass-spectrometer will increase, also reducing its sensitivity. This effect can be avoided, by integrating ion selector and collision cell into one unit.
摘要:
The invention relates to an activation circuit for a Pockels cell, comprising a first circuit node (P1), which can be connected to a first connection of the Pockels cell (CP), and a second circuit node (P2), which can be connected to a second connection of the Pockels cell (CP), wherein the first circuit node (P1) is connected by means of a first line to a first electrical potential (HV1) across a first switch (S1B) and by means of a second line to a second electrical potential (HV2) across a second switch (S1A), and the second circuit node (P2) is connected by means of a third line to a third electrical potential (HV3) across a third switch (S2B) and to a fourth electrical potential (HV4) across a fourth switch (S2A), and HV1 is more positive than HV2 and HV3 is more positive than HV4, wherein the difference of the potentials (HV1−HV4) is greater than the difference of the potentials (HV1−HV2) and the difference of the potentials (HV3−HV4).
摘要:
This invention relates to a method for generating bursts of laser pulses and to an apparatus for generating bursts of laser pulses and to a Pockels cell driving circuit. A method for generating bursts of laser pulses comprising generating first repetition rate laser pulses, and generating first repetition rate laser bursts from the repetition laser pulses, the laser bursts each containing a sequence of second repetition rate laser pulses, wherein the second repetition rate is higher than the first repetition rate.
摘要:
The present disclosure relates to a high voltage switch which may comprise a chain of MOS field-effect transistors (MOSFETs). The current of the individual MOSFETS, and hence the chain, can be controlled by means of adding a current measuring resistance into the source path of the transistors and transmitting the voltage arising there via a capacitor to a gate connector of the transistors.
摘要:
A mass spectrometric analysis of the content of surfaces, it is necessary to bring the analyte molecules into the gas phase. This is done with a tightly focused, preferably pulsed laser beam. This laser beam is focused onto the surface with a mirror that is placed as close as possible to the analysed surface. In order to achieve a very small focal point, deflection and focusing of the laser beam is done with a single optical element. The evaporated material passes through a opening in the mirror into the mass spectrometer. It is also possible to let the evaporated material pass right next to the mirror into the mass spectrometer.
摘要:
Driver for Pockels cells and using this Pockels cell within laser systemsThe driver i.e. the electrical control of the Pockels cell is modified from the standardly known H-configuration using the switches S1, S2A; S1A, S2 A by adding at least one more switch (S2B; S1B; S2B). This switch can either replace the usually used recharging resistors (R2) or can be placed to these in parallel. It is also possible to use an arrangement using 4 switches (S1A, S2A, S1B, S2B) and no recharging resistors at all. Using such a driver with a Pockels cell pulses can be selected in laser systems more efficiently. Pulse sequences with well defined widths and spacing can be produced for certain application.
摘要:
In order to effect fragmentation of ions through collisions with gas-phase molecules, it is necessary to have a high gas pressure in the collision region. At the same time the residual gas pressure in the detector region of a mass-spectrometer must be kept low. This is done by arranging collision cell and detector into separately pumped vacuum regions, each region having its own pumping port, the regions only being connected via flow restrictions in the vicinity of the ion optical axis. Achieving large pressure gradients and at the same time not reducing the sensitivity of the mass spectrometer can be done by using gas flow restrictions with large cross sections. A very efficient and space saving arrangment is to place a separate chamber with the collision cell between the chamber housing the reflector and the detector and the chamber housing the ion source of the mass spectrometer.
摘要:
The present disclosure relates to a high voltage switch which may comprise a chain of MOS field-effect transistors (MOSFETs). The current of the individual MOSFETS, and hence the chain, can be controlled by means of adding a current measuring resistance into the source path of the transistors and transmitting the voltage arising there via a capacitor to a gate connector of the transistors.
摘要:
The invention relates to an activation circuit for a Pockels cell, comprising a first circuit node (P1), which can be connected to a first connection of the Pockels cell (CP), and a second circuit node (P2), which can be connected to a second connection of the Pockels cell (CP), wherein the first circuit node (P1) is connected by means of a first line to a first electrical potential (HV1) across a first switch (S1B) and by means of a second line to a second electrical potential (HV2) across a second switch (S1A), and the second circuit node (P2) is connected by means of a third line to a third electrical potential (HV3) across a third switch (S2B) and to a fourth electrical potential (HV4) across a fourth switch (S2A), and HV1 is more positive than HV2 and HV3 is more positive than HV4, wherein the difference of the potentials (HV1−HV4) is greater than the difference of the potentials (HV1−HV2) and the difference of the potentials (HV3−HV4).