The Endstations

A: The sample manipulators

In the Main chamber , the sample manipulator is mounted vertically on top of the experimental chamber. In the Main chamber two manipulators are available.
  One is a LHe cryostat with 4 degrees of freedom. Its main features are the following:
X-Y (horizontal) travel = ±25 mm; Z (vertical) travel = 200 mm; Angular rotation (polar) = ±180°
Temperature range: 30 K (LHe) or 90 K (LN2)÷1000 K; IMPORTANT: This manipulator is currently not available (May 2009) because it is in repair. The present manipulator installed on the BACH endstation is get on load from Universita' Cattolica di Brescia. It is a CREATEC LHe cryostat with 4 degrees of freedom (XYZpolar). The minimum temperature of this manipulator is 30 or 50  K with LHe and 100-110 K with LN2 on the sample holder. The minimum temperature depends on the sample holder which is used. For instance using the new VG XL25HC sample holder with PBN and thermoucouple we have reached -4.3 mV on the sample (~100 K).
The temperature range is 250÷1500 K with home-made sample holders, for Si, SiC and Ge.
IMPORTANT: If you need to flash your sample above 1000 K, please contact the beamline

The other manipulator is a 5-degrees of freedom Omniax manipulator made by VG. This manipulator is currently installed on the branch B for time resolved XAS (without azimuth). We recommend prospective users to contact the beamline staff if they are interested to use the 5-axis Omniax instead of the Createc on the branch line A. Its main features are the following:
X-Y (horizontal) travel = ±25 mm; Z (vertical) travel = 200 mm; Angular rotation (polar and azimuthal) = ±180°;IMPORTANT NOTICE: Azimuthal rotation is not available at BACH now
Temperature range of the  5-degrees of freedom Omniax: 130÷1000 K (with XL25HC sample holder);

In the Preparation chamber we have an home-made manipulator (the so called "garage") which can host up to three sample carriers and which can be used for parking the samples in UHV or anneal the samples with direct current up to 10 Amp or using a PBN (up to ~700-800 degree Celsius). Annealing is possible also during the evaporation.

A: The sample holders

There are several sample carriers: standard VG (XL25VH and XL25HC) and home-made carriers for heating by filament for radiative sample heating (up to 300° C) or electron bombardment (available only under special requests) or direct current flow (max 10 Amp, sample always grounded).
For dimensions and further information on the sample holders please download the pdf from the VG-Scienta website:

PDF FILE (Standard VG Sample Holder)

Note: The maximum current which can be applied in continuous is 1.2 A!

The samples

The Samples must be conductive for photoemission measurements. The sample holder can host one or more samples in a square area of about 25x25 mm. The samples can be fixed by conductive UHV compatible glue, UHV-compatible carbon/copper tape, by Mo clamps (up to 4), or it can be sandwiched between the sample holder body and a Mo/Stainless steel cap with one hole of different sizes and shapes. For Si, Ge and SiC the sample should be cut in a rectangular piece (IDEAL: 3.5 mm x 8 mm. However, it can fit also 3-4 mm x 7-9 mm).



IMPORTANT INFORMATION FOR IN-SITU SAMPLE PREPARATION! If the sample needs to be prepared in situ, the sample must be sent to the contact person at the BACH beamline, arranging the delivery so that they can be mounted and transferred in the preparation chamber at least 10 days before the experimental run in order to properly degass the sample holder. When annealing is required, the sample will be typically holded between two plates (one below and one above, with one hole of the proper size and shape to hold the sample). Please specify if there is incompatibility (e.g. alloy formation during annealing) with any material possibly used for the sample holder plate. We typically use: Mo or stainless steel. If you have special requests please contact your local contact well in advace and if necessary provide a 0.1-0.125 mm plate of the material.

Last Updated on Wednesday, 06 March 2024 10:24