[trARPES] Fwd: AW: METIS alignment

Ralph Ernstorfer ernstorfer at fhi-berlin.mpg.de
Sat Jun 30 06:57:58 CEST 2018


this is Hajo's email. It was also flagged as spam in my account, but I
could retrieve it.
  r



-------- Forwarded Message --------
Subject: 	Re: AW: METIS alignment
Date: 	Sun, 24 Jun 2018 18:17:40 +0000
From: 	Elmers, Hans-Joachim <elmers at uni-mainz.de>
To: 	Ralph Ernstorfer <ernstorfer at fhi-berlin.mpg.de>, Schönhense, Prof.
Dr. Gerd <schoenhe at uni-mainz.de>
CC: 	Laurenz Rettig <rettig at fhi-berlin.mpg.de>, Dong Shuo
<dong at fhi-berlin.mpg.de>, Maciej Dendzik <dendzik at fhi-berlin.mpg.de>,
Yoav William Windsor <windsor at fhi-berlin.mpg.de>, Rui Patrick Xian
<xian at fhi-berlin.mpg.de>, Beaulieu, Samuel <beaulieu at fhi-berlin.mpg.de>



Dear Ralph,


here I am sending you the Ekintokz converter that we were using

for that what the name says.

Very helpful is the TransformJ plugin from Fiji (just another imagej)

that allows affine transformation of the dataset.


Kind regards, Hajo

------------------------------------------------------------------------
*From:* Ralph Ernstorfer <ernstorfer at fhi-berlin.mpg.de>
*Sent:* Saturday, June 23, 2018 2:06:45 PM
*To:* Schönhense, Prof. Dr. Gerd; Elmers, Hans-Joachim
*Cc:* Laurenz Rettig; Dong Shuo; Maciej Dendzik; Yoav William Windsor;
Rui Patrick Xian; Beaulieu, Samuel; Yoav William Windsor
*Subject:* Re: AW: METIS alignment
 

Dear Gerd,

coming back to the various corrections one can/must apply to the METIS
data: we need to implement these corrections in our data processing work
flow. I would very much prefer to build on your experience and codes
rather than starting from scratch. Are you (meaning everyone who was
involved in developing this) willing to share this code with us?


Has Ben's code been adopted to the data format of the FLASH experiment
and applied to the data you measured last fall, e.g. by Steinn and
Davide? Has it even been shared already on github or Yves's ETH-internal
git?


Cheers,
  Ralph



On 06.06.2018 12:17, Schönhense, Prof. Dr. Gerd wrote:
>
> Hallo Ralph,
>
>
> in Ben's paper sind die meisten Punkte beschrieben. Die spacecharge
> correction ist ein Python code von Ben, den wir ständig benutzen.
> Darin sind auch Routinen zur Beseitigung der Kippung der Achse,
> DLD-grid removal etc.
>
> Die Spulen hatte ich in unserm Fall mit einadrigem Draht direkt auf
> die Rohre unmittelbar hinter den Flanschen aufgewickelt, 20 Wdg. Am
> besten eine am Übergang Spincross -Mik.halter und eine am Übergang
> Mik.halter-Kammerflansch. Sie können auch leicht zum Entmagnetisieren
> benutzt werden, bipolar hin und herfahren mit verringerter Amplitude.
>
> Halt mich über Settings auf dem Laufenden, wie gesagt, aus dem
> Programm Werte mit verschiedenem M (z.B. M=3) probieren.
>
>
> Viele Grüsse
>
> Gerd
>
>
> ------------------------------------------------------------------------
> *Von:* Ralph Ernstorfer <ernstorfer at fhi-berlin.mpg.de>
> *Gesendet:* Mittwoch, 6. Juni 2018 16:37:43
> *An:* Schönhense, Prof. Dr. Gerd; Elmers, Hans-Joachim
> *Cc:* Laurenz Rettig; Dong Shuo; Maciej Dendzik; Yoav William Windsor;
> Rui Patrick Xian
> *Betreff:* Re: METIS alignment
>  
>
> Dear Gerd,
>
> thank you for the data correction / conversion, and for the
> 'calibration' of the data quality. Good to hear you consider this high
> quality.
>
>
> Is there a summary / paper / thesis describing the different
> post-processing procedures that you employ to correct for the various
> types of experimental imperfections? Our main data format will be
> single events in hdf5, so it would make a lot of sense to integrate
> procedures you developed and tested in the past to our data analysis
> work flow.
>
>
> Regarding the Helmholtz coils: which diameter did you roughly use?
>
>
> Cheers,
>   Ralph
>
>
>
> Am 06.06.2018 um 10:58 schrieb Schönhense, Prof. Dr. Gerd:
>>
>> Dear Ralph, dear all,
>>
>>
>> thanks for the files!
>>
>> I binned them, made fast rotate/rescaley0.95 correction and also made
>> gifs (that run on mouseclick), see attachments. From our point of
>> view ( on our "quality scale")  this is excellent, CONGRATS!!
>>
>>
>> We encounter one issue here that we did not communicate in the past:
>> ALL images we have ever taken have a residual tilt of the energy axis
>> due to stray fields or sample tilt or misalignment of photon spot
>> and/or field aperture, uneven sample surfaces etc. I think this needs
>> to be stated in the manual...
>>
>> The low energy patterns we took when Hajo and me were there and your
>> attached measurement is one of the best we ever saw. Hajo can confirm
>> that.
>>
>>
>> Having a straight optical axis over 16eV wide energy range requires
>> magnetic field close to zero on the axis which none of the present
>> instruments has. And these are "extremely-low-energy-microscopes"
>> which are perfect magnetometers. I feel that a second shielding is
>> necessary (which is standard for high-res hemispheres).
>>
>>
>> If you want you may try the Helmholtz coils around the critical
>> flanges, maybe even for both. Just 10-adriges Kabel two turns or
>> 5-adriges 4 turns, all connected in series and simple powersupply for
>> 5 Amps (e.g. Distrelec). This is how I made it in Mainz.
>>
>>
>> Viele Gruesse
>>
>> Gerd
>>
>>
>>
>> ------------------------------------------------------------------------
>> *Von:* Ralph Ernstorfer <ernstorfer at fhi-berlin.mpg.de>
>> *Gesendet:* Mittwoch, 6. Juni 2018 07:50:14
>> *An:* Schönhense, Prof. Dr. Gerd; Elmers, Hans-Joachim
>> *Cc:* Laurenz Rettig; Dong Shuo; Maciej Dendzik; Yoav William
>> Windsor; Rui Patrick Xian
>> *Betreff:* METIS alignment
>>  
>> Dear Gerd and Hajo,
>>
>> thanks a lot for your visit yesterday. This was very helpful for us.
>>
>> After you left, we changed photon energy and sample (22 eV, WSe2). We
>> realized that the settings we had converged to aren't working for these
>> conditions as the top-right corner of the photoemission horizon got
>> cliped at some hard (= not movable edge), possibly at the extractor
>> aperture.
>>
>> We tried to optimize under the constraint that we see a centered and
>> unclipped k space signal. Unfortunately, this we could only achieve with
>> distorted k space imaging, i.e. the shadows of the CS grid were not
>> straight in XT and YT planes.
>>
>> We put two data sets (with and without CA grid) in this drive:
>> https://owncloud.fhi-berlin.mpg.de/owncloud/index.php/s/B9YrAiOia7FqyfK
>>
>> It would be great if you could take a look at this and let us know if
>> you have ideas on how to optimize this further.
>>
>> Besides this distortion, the data looks very good. We acquired with a
>> count rate of ~2e5, i.e. about half the repetition rate. At first sight,
>> we seem to have a good contrast around the Fermi level, which will be
>> important for pump-probe measurements, i.e. no obvious 'Oelsner effect'.
>>
>> You mentioned your 'cheap&dirty' homegrown mercury lamps. We are
>> definitely interested in this and it would be great if you could share
>> the design/list of components or, even better, sell us such a lamp.
>>
>> Good luck at your beam time!
>>   Ralph
>>
>> -- 
>> Ralph Ernstorfer                            ernstorfer at fhi-berlin.mpg.de
>> Research Group Structural and Electronic Surface Dynamics
>> ERC project FLATLAND
>> Fritz Haber Institute
>> Faradayweg 4-6                              Tel: +49 30 8413-5117
>> 14195 Berlin                                Fax: +49 30 8413-5387
>> Germany
>> http://w0.rz-berlin.mpg.de/pc/ernstorfer/
>>
>
> -- 
> Ralph Ernstorfer                            ernstorfer at fhi-berlin.mpg.de
> Research Group Structural and Electronic Surface Dynamics
> ERC project FLATLAND
> Fritz Haber Institute
> Faradayweg 4-6                              Tel: +49 30 8413-5117
> 14195 Berlin                                Fax: +49 30 8413-5387
> Germany
> http://w0.rz-berlin.mpg.de/pc/ernstorfer/
> ----------------------------------------------------------------------
> Das FHI verarbeitet, speichert und loescht Daten im Rahmen seiner
> Geschaeftstaetigkeit gemaess der Datenschutz-Grundverordnung (DSGVO)
> [General Data Protection Regulation (GDPR)] der Europaeischen Union.

-- 
Ralph Ernstorfer                            ernstorfer at fhi-berlin.mpg.de
Research Group Structural and Electronic Surface Dynamics
ERC project FLATLAND
Fritz Haber Institute
Faradayweg 4-6                              Tel: +49 30 8413-5117
14195 Berlin                                Fax: +49 30 8413-5387
Germany
http://w0.rz-berlin.mpg.de/pc/ernstorfer/

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