Yael Kempe |  yael.kempe@mail.huji.ac.il

In our lab, we have a JEOL Superprobe JXA-8230. The EPMA designed for chemical analysis of the characteristic X-Rays emitted from a sample when probed by an electron beam. An EPMA can quantify elemental concentration using electron dispersive spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS) to detect and count characteristic X-Rays emitted from a sample. There are pros and cons to using the EDS and WDS detector (mainly time and the necessity of experience using the techniques). We will be happy to discuss these in person

Key features

Imaging options in the EPMA:

 

• Back scattered electron imaging (BSEI) is sensitive to the mean electron density (atomic weight). Back scattered electrons ate a form of elastic scattering in which incoming incident electrons are bounced back off the sample to hit the detector. 
   
• Secondary electron imaging (SEI) reveals the sample's topography due to the variation in SE production at different tilt angles. Secondary electrons ejected from the k-shell by inelastic scattering interactions with the electron beam. They originate within a few nanometers of the surface. 
   
• Cathodoluminescence (CL) Promotion of valence band electron to conducting band can emit photon of electromagnetic radiation in the visible light region. 

Chemical analysis in the EPMA:  

• EDS Detector: Energy dispersive spectroscopy counts the number and energy of X-Rays emitted from a specimen. The energy spectrum of the X-Rays characterizes the atomic structure of the emitting element.
   
•   WDS Detector: Wavelengthe dispersive spectroscopy counts the number of X-Rays of a specific wavelength diffracted by a crystal. In contrast to EDS, WDS detectors only count the X-Rays of a single wavelength at one time that characterize the atomic structure of the emitting element

Term and conditions

 

• The price per hour is valid only for users who have opened a credit account of 9000 ₪.
   
• The price per hour is valid only for user's with credit in the account.
   
• Users cannot book when the account is in debt.
   
• Users can book for the current and the next month only.
   
• Users cannot book more than 3 days in a row.
   
• At the time of booking, you are required to provide the following information: sample type, analysis type, required elements, and analysis goal.
   
• Booking time should be according to the attached table:

 

 

	Standard deviation	Detection limit (ppm)	Min booking days
Imaging (SEI, BSE, CL)			1
EDS (Factory setup)	5%	1000	1
EDS (Mineral calibration)	3%	500-1000	1-2*
WDS	0.5-1%	40-100	2-3*

* Depends on a project.

 

• WDS calibration cannot be performed on the same day as the analyses.
   
• It is not possible to change the type of analysis or change calibration on the same day of the analyses.
   
• WDS calibration takes about two hours per mineral and can be performed only by the lab staff.
   
• The user can cancel an appointment without charge up to 24 hours before.
   
• Calibration is performed on existing SPI standards (minerals and metals).
   
• If specific standards are needed. It is the user's responsibility to provide them. 

 

• Types and sizes of samples:
   

  	Size	Depth	Max samples
  Epoxy mounts	1" (outside diameter)	1"	6
  Thin sections	4.5 X 2.6 cm		3
  Thick samples	4.5 X 2.6 cm	1 cm	3
  Large samples	7.5 X 3.5 cm	0.2 cm	1
  Small samples	<1"	<1"	6

• All samples must be approved by the lab staff before entering the EPMA.
   

• The user is responsible for preparing his samples prior to the day of analyses (cutting, epoxy, polishing). Remember: epoxy must be prepared 48 hrs before analysis (the lab does not provide epoxy).
   

• Sample preparation should be done prior to the day of analyses.
   

• Polishing the samples is the user responsibility with lab staff guidance.
   

• Coatings are is the lab staff responsibility.
   

• Changing samples are under lab staff responsibility only.
   

• The entrance to the lab is shoeless. The user should come with socks or get shoes from the lab. You will not be able to enter barefoot.
   

• User can work independently only after appropriate training and the approval of the lab manager.
   

• The lab manager can deny a user from independent work.
   

• During unassisted time at the instrument, the user if fully liable for any damage resulted on the EPMA instrument or accessory.
   

• It is user's responsibility to retrieve, back up, and process its data.
   

• The lab staff will not send the data electronically. The user can send it to himself from the lab computer.
   

• The lab is not a storage facility. Users are responsible to take their samples back at the end of analyses.
   

• For any further questions, please feel free to contact the lab staff.

   

   

Service rates

The price per hour is valid only for users who have opened a credit account of 9000 ₪.

 

 

users	Per hour		Per day		Sample Preparation**
	Independent	Assist	Independent	Assist
IES	150	200	900	1200	50
HUJI	200	300	1200	1800	50
Academic	250	450	1500	2700	50
Industry	Please contact for quote

 

* All price in NIS.

** Price per sample. (A set of small samples on one mount considered as one)

 

Contact person

 

 

EPMA Laboratory Manager : 

 

Yael Kempe | yael.kempe@mail.huji.ac.il

 

Laboratory head: 

Professor Oded Navon

 

How to order