High Density VUV Source for UPS, ARPES, PEEM and µ-ARPES
The HIS 14 HD lamp is based on the HIS 13 with an additional focussing mirror. The focussing mirror provides ideal conditions for high resolution ARPES: a spot size of 180 µm enabling high angular resolution with classical ARPES analyzers and at the same time delivering a photon density which allows for angular resolved photoemission spectroscopy close to synchrotron performance level.
Key Features
- Long lifetime due to filament free design
- 180 µm spot size
- photon density up to 1.1·1013 Ph/mm2/s
- Large working distance (up to 200 mm)
- line of sight viewport
- Operating pressure in the 10-10 mbar range
- Ease of operation
The large working distance of 60 mm makes the HIS 14 HD fully compatible with the acceptance angle- and working distance requirements of high performance ARPES analyzers.
The optical view port at the back of the source allows to check the discharge conditions and provides line-of-sight view onto the sample for precise beam spot alignment.
Spot Profile of HIS 14 HD
The focused light spot from a cold-light source is imaged using a diffusing screen with a scale and a light microscope. Note that the foot base width of the peak is 380 µm with a HeI photon flux of 2.2·1012 Ph/s/mm2 .
Typical HIS 14 HD/analyser configuration
The HIS 14 HD can be installed on a dedicated flange (new systems) or retrofitted to an existing chamber. Please contact us for individual clarification.
Micro-ARPES on Graphene with the HIS 14 HD
This 4D data cube of a monolayer graphene on SiC was acquired with the HIS 14 HD and He I exitation in the NanoESCA. The data set ranging from the Fermi level down to almost 6 eV binding energy was acquired at room temperature on a 30 µm FOV with a 100 meV analyzer resolution.
Courtesy Philip Rosenzweig, Max-Planck-Institut für Festkörperforschung in Stuttgart
Power Supply
The VUV source power supply is a fully digital unit with integrated pressure measurement and automated plasma ignition. It delivers up to 1 kV anode voltage, up to 300 mA discharge current and a very stable discharge regulation.
Key Features
- fully digital unit design
- Discharge regulation
- Integrated pressure measurement
- More than 300 installed units
- Automated plasma ignition
- Ease of operation
- 1 kV discharge voltage
- 300 mA discharge current
Technical Specifications
The working distance and focussing capabilities of the HIS 14 HD are a property of its focussing mirror. The spot diameter and the photon density vary slightly with the chosen light capillary diameter which is mounted prior to the focussing mirror. We recommend the 1.2 mm capillary due to its low He gas flow into the analysis chamber, which is further reduced by an additional differential pumping stage.
The HIS 14 HD with 70 mm working distance meets the following specifications:
| Capillary Diameter (mm) | 0.8 | 1.2 | 1.7 |
|---|---|---|---|
| Spot Diameter (mm) | |||
| • at 70 mm working distance | 0.18 | 0.22 | 0.28 |
| Photon Density (Ph/s/mm2) | |||
| • at 70 mm working distance | 6.0 · 1012 | 1.1 · 1013 |
The HIS 14 HD 200 is designed for an extra long working distance and meets the following specifications:
| Capillary Diameter (mm) | 1.2 |
|---|---|
| Spot Diameter (mm) | |
| • at 160 mm working distance | 0.43 |
| Photon Density (Ph/s/mm2) | |
| • at 160 mm working distance | 2.0 · 1012 |
Further features of the lamp are:
| Feature | Specification |
|---|---|
| Useful gas discharge lines: | He I/II, NeI/II, ArI/II, KrI/II, XeI/II, H (Lyα, Lyβ) |
| Spot diameter: | < 300 µm (fwhm; 5:1 demagnifying optics) |
| Photon line width: | < 2 meV (HeI radiation) |
| Photon flux density: | >50 times compared to an unfocused source |
| Source alignment: | CF 63 port aligner |
| Pumping: | 2- or 3-stage differential pumping |
| Working distance: | Ca. 70 mm (clearance to measurement position) |
| Insertion depth: | Customized (to be defined) |
| Mounting flange: | DN 63 CF of DN 100 CF |
| Operating pressure: | Down to 10-10 mbar range |
| Adjustment & Discharge control | Via backside viewport |
| Cooling: | Water cooling |
| Bake out temperature: | Up to 250° C |
| Plasma Ignition: | Automatic |
| Capillary (mm): | 0.8 / 1.2 / 1.7 (standard) / 2.2 |
Technical Drawings
The drawing shows the standard configuration of a HIS 14 HD.
The HIS 14 HD 200 is designed for an extra large distance between sample and light source.
Optional Upgrades for HIS 14 HD
The VUV lamp HIS 14 HD is extendable with all available options such as a 3rd differential pumping stage and an attenuator to tune light intensity, as well as a longer focal length mirror and a the FOCUS HIS monochromator. All these options can be combined.
Third differential pumping stage
The VUV lamp HIS 14 is extendable with all available options such as a 3rd differential pumping stage, an attenuator to tune light intensity, linear polarizer, a monochromator and two different focusing mirrors. The standard 2-stage differential pumping allows for a system pressure of 10-8 – 10-9 mbar during operation for He I. The third pumping stage reduces the pressure to the mid 10-10 mbar range depending on capillary diameter.
Attenuator
Even though most application in photo electron spectroscopy aim for maximum intensity there are opposite requirements when working on VUV-sensitive sample as for example organic materials. The Attenuator for HIS 13/14 allows for a variable reduction of photon flux by a factor 10 or 100.
Focusing mirror with different focal length (CF40 mounting flange)
With a flange to sample distance of up to 160 mm the HIS 14 HD 200 allows for a CF 40 mounting flange using a mirror with double focal length: 200 mm instead of 100. 200 mm focal length result in a spot size of 350 µm and a photon flux of 5 ·1011 Ph/s/mm2
