Hi Radoslaw,

Unless I am mistaking, historically the “J” indicate that the monochromator geometry is of “Johansson” type (in opposite to Johann). The Johansson geometry has the 2d lattice bent at a radius of 2R, and the monochromator is then further grinded to a R radius, offering thus a perfect focusing of the X-ray on the detector.

Nowadays it is common to still see it on the PET monochromator (PETJ) but I haven’t seen it on other monochromator… 

Best,

Julien


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Dr. Julien Allaz
Head assistant for SEM/EPMA
Inst. für Geochemie und Petrologie
ETH Zürich
NW E 84
Clausiusstrasse 25
8092 Zürich
Switzerland

Tel: +41 44 632 37 20
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On 23 Sep 2020, at 10:10, Michallik Radoslaw (GTK) <[log in to unmask]> wrote:

Hi,
 
I’ve been working on an old JEOL JXA 8600 with the normal “small size” x-tals i.e. TAP. I know that large crystals are i.e. TAPL (normal spectrometer 140mm) and high intensity crystals are TAPH for the H-Type spectrometer with a smaller Rowland circle (100mm).
 
But what are i.e. TAPJ x-tals? What does the “J” stands for? I’ve noticed that they are usually mounted with a gas-flow proportional counter.
 
I just started recently at my new work place and we’ll have a configuration with TAPJ and PETJ crystals on our new FE-EPMA from JEOL.
 
Thank you in advance for your help.
 
 
Kind regards,
 
 
 
Radoslaw Michallik
Researcher
Circular Economy Solutions
Geological Survey of Finland GTK
 
Vuorimiehentie 2K, FI-02151 Espoo, Finland
Tel. +358 29 503 0345, +358 50 340 9701
 
 
The Geological Survey of Finland provides solutions for more sustainable growth.
For Earth and for Us.
 
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