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Introduction

The Hard X-ray Nanoprobe (HXN) beamline at NSLS-II is a powerful tool for studying materials at the nanoscale level. It uses two x-ray microscopes that can operate in the energy range of 6 to 18 keV and achieve a spatial resolution of 10 nm. The HXN beamline can also perform multimodal characterization of different types of materials, such as metals, ceramics, polymers, and biological samples. Moreover, the HXN beamline has various in situ capabilities that allow researchers to observe how materials behave under different conditions. The HXN beamline is controlled by EPICS, a software framework for distributed control systems. The data acquisition is done using Bluesky, a Python-based software package developed at NSLS-II. The data analysis is supported by a suite of software tools that enable image processing, visualization, and quantification. Read more about the beamline capabilities on our webpage. Read our experimental procedures for standard experiments here.

Sample Preparation

Sample preparation step is very critical to get useful data in reasonable time frame. Before you start your experiment, you need to prepare your sample in a way that ensures its stability and quality under the beam conditions. This may involve cutting, polishing, coating, mounting, or aligning your sample depending on the type and size of the material you are studying. The beamline staff can assist you with the appropriate equipment and techniques for your sample preparation. They can also advise you on how to optimize your data collection and analysis based on your sample characteristics and research goals. The following is a brief overview of some common steps involved in sample preparation for different types of experiments. Please talk to beamline staff for specific details.

Sample size considerations

If you want to scan a sample with our high resolution scanner, you need to know some important parameters. The scanner can only cover a range of 30umx30um in one 2D scan, so you have to adjust your sample size accordingly. The resolution and time are also factors that affect the quality and duration of the scan. The microscope you use (zone plate vs mll) determines the step size you need for the best resolution. For zone plate, it is 30 nm and for mll, it is 10 nm. You can change these values for different purposes, but we usually do. Another parameter is the exposure time, which depends on the type of sample. For metallic nanoparticles, we use 0.03 second and for bio-imaging of trace elements, we use 0.25 second. To calculate the experimental time of one 2D image, you can use this formula: (X_dim/X_resolution)x(Y_dim/Y_resolution)*exposure_time. For example, if you scan a 5x5 um sample with zone plate using 50 nm step size and and 0.03 second exposure time, the experimental time is (5000/50)x(5000/50)x0.03 = 300 seconds.Tomography and xanes are examples of high level scans that require more time than just 2D imaging methods. This is because they need to capture multiple 2D images at different angles or energies. A typical measurement at HXN can last up to a day for one sample, for these techniques.

Substrates/Tomo Pins

Name	Vendor /Link	Part Number	Details	Notes
Diving Boards	Norcada	NCT4155P-IV-Cr	Si membrane 10-pack Frame: 3.5mmx1.5mm, 300um silicon Membrane size: 0.50mm x 1.40mm Membrane: 10um <100> Silicon P-type + 20nm SiNx Fiducial markers: ~50nm thick Chromium	Good for all microscopes
Si3N4 Windows	Norcada	NXCT-0101-Cr-I	SiNx Membrane 10-pack Membrane: 1.50mmx2.00mm, 200nm thick Frame: 5mmx5mm, 200µm thick Silicon Fiducial marks: ~50nm Cr	preferred for bio-imaging and low-Z elements mapping, Not good for MLL microscope
Open-Edge SiN Windows for X-ray Tomography	Norcada	NCT4155P-III-CrPt	Frame: 3.5mmx1.5mm, 300μm Silicon Membrane size: 0.5mmx1.4mm Membrane thickness: 10μm <100> Silicon P-type / 20nm SiNx Membrane fiducial markers: 50nm Chromium + 50nm Platinum Maximum unobstructed viewing angle: 320 degrees	NCT4155P-II-Pt or NCT4155P-II-Cr are also fine
Stainless Steel Tomo Pins	Fine Science Tools	7000-10 (part # 26001-25 cut to 18mm length)	Tip Diameter: 0.03mm Rod Diameter: 0.25mm Material: Stainless Steel Length: 18mm
Tungsten Tomo Pins	Fine Science Tools	10130-05	Tip Diameter: 0.001mm Rod Diameter: 0.125mm Material: Tungsten Carbide Length: 12mm

Sample Mounting

The sample holder for the microscope consists of a custom Al-pin that can accommodate 2-5 grids depending on the choice of substrates. The membranes are attached to the grids using glue (nail polish is common) and then mounted on the pin. The specifications of the sample holder are given below. These pins are available at the beamline. Contact the beamline staff if you need them shipped to your home institute. The following diagrams show how to mount an HXN Sample to the pin using different options.

HXN Sample mounting

PDF

Sample Loading/Exchange

The next step in loading the aluminum sample holder with windows or pins for microscopic analysis is to place securely on the microscope stage. To do this, you need to use the holes on the sample mount as a guide to align the sample with the stage. The image below shows holder the position on the stage. After placing the sample, you need to use a special nut to fasten the holder and prevent any movement of the sample during observation.

Microscope and Sample Stage Images

Some details of the microscope maybe found in this document HXN Microscope ZP

In situ Heating Stage

Heating Stages

Data Collection

To perform experiments at HXN, users can choose one of the two methods available to collect data: command line based method or graphical user interface (GUI) method. The command line based method allows users to write scripts and execute commands directly on the terminal. This method is more flexible and powerful, but also requires more programming skills and familiarity with the beamline software. The GUI method provides a user-friendly interface that simplifies the data collection process . This method is easier and faster, but also has some limitations and may not support all the features of the beamline. Users can switch between the two methods at any time during their experiment, depending on their needs and preferences.

To operate the beamline and the experimental stations, NSLS-II uses a software platform called CS Studio (CSS) that allows users to monitor and control various parameters and devices. One of the devices that can be controlled by CSS is the motor, which is used to move and align the sample and the detector. The HXN-GUI is a graphical user interface that provides access to the most important motors for navigation and alignment at the beamline. The HXN-GUI also displays some parameters from CSS, such as the current position and the status of the motors. Users can switch between the HXN-GUI and the CSS windows when necessary, depending on their needs.

BSUI Command line

At NSLS-II, we use a software framework called Bluesky to control our experiments and collect data. Bluesky is a python-based library that provides a flexible and powerful way to define scan plans and record metadata. To use Bluesky, you need to have a basic understanding of python syntax and commands. However, you don't need to be an expert programmer, as the beamline staff and manual will guide you through the process of using Bluesky at our beamline. The HXN beamline manual contains specific information about how to operate the microscope with Bluesky, as well as some examples of common scan plans. You can also find general Bluesky tutorials and documentation here.

HXN Manual

Data Transfer

There are several options available to access your data from the beamline. The beamline scientists will guide you on obtaining the data in the required format and saving it to your directory at the beamline. From there, you have the following options to transfer the data to your own systems:

1. USB Drive or Approved Cloud Service: You can copy the data to your own systems using a USB drive or an ITD approved cloud service such as OneDrive.
2. File Transfer Protocol (FTP): You can utilize a file transfer protocol with your BNL domain account. Win/Mac/Linux users can utilize SCP commands. For instance, Mac users can use the following command in their terminal :scp -J username@ssh.nsls2.bnl.gov -r username@xf03idc-ws2:/source_directory/ /destination_directory/Replace username with your BNL domain account username, source_directory and destination_directory with the respective paths. MobaXterm software provides a user-friendly solution to SCP specifically for Windows users (see moba settings below)
3. Use rsync for larger files; rsync -av -e 'ssh -J username@ssh.nsls2.bnl.gov' username@xf03idc-ws2:/source_directory/ local/destination_directory/

These options allow you to effectively access and transfer the data acquired from the beamline for further analysis and processing on your own systems.

FAQ

Note that the answers are general and may not apply to every situation or context. The purpose of these answersis to provide some basic information and guidance. I For more specific or detailed information, please contact the beamline staff.

How long it takes to measure one sample?

Typically one day, unless you are doing collecting 2D images of your samples at different places.

The below paragrap explains how to estimate the experimental time for different types of scans at HXN.

The experimental time for a scan depends on the type of scan, the size of the sample, the resolution and the exposure time. A simple way to calculate the experimental time for a 2D image is to multiply the number of pixels in each dimension by the exposure time. For example, if you want to scan a 5x5 um sample with a 50 nm step size and a 0.03 second exposure time, you can use this formula: (5000/50)x(5000/50)x0.03 = 300 seconds. This means it will take 300 seconds to acquire one 2D image of your sample.

Some scans require more than one 2D image, such as tomography and xanes. These are high level scans that need to capture multiple 2D images at different angles or energies. To calculate the experimental time for these scans, you need to multiply the experimental time for one 2D image by the number of projections or energies. For example, if you want to do a tomography scan with 90 projections, you can use this formula: 90x(5000/50)x(5000/50)x0.03 = 27000 seconds. This means it will take 27000 seconds (or more than 7 hours) to acquire one tomography dataset of your sample. There is always an overhead for each scans that is typically +25-50% to the scan time.

How long is a typical beamtime?

Minimum 3 days = 9 shifts

What's the lowest incident energy?

5.9 keV

How long it takes to change the sample?

up to 2 hours for exchange + vacuum. up to 3 hours for alignment

What's the sample environment?

Helium is used as a buffer gas (because of low scattering and thermal conductivity). The typical pressure for Helium is 250 mm of Hg. However, some experiments may require lower pressures to reduce the background noise or increase the signal-to-noise ratio. In such cases, the chamber can be pumped down to a high vacuum level of up to 10e-6, We cannot operate in air.

What is the shipping address?

ATTN:Beamline Scientist's Name

National Synchrotron Light Source II

Bldg. 743

Brookhaven National Laboratory

Upton, NY 11973-5000

Remote Access

If you want to log in to the beamline systems remotely, you can find the instructions and requirements in this link. This link contains general information for all users, so please read it carefully before you start. The beamline scientists can also grant you access to guacamole, which is a web-based interface that allows you to view the data collection monitors. Depending on your user level, you may also be grant to control the beamline using guacamole, but this is up to the the beamline scientists.