social atmosphere

so nic asked me about the social atmosphere. here is a snapshot from the beamline. everybody else is probably around reeperbahn.

wishlist for next beamtime

small water leveller
window valve cf35 for beamline
can of dry air
torr seal (vacuum compartible glue)
more?!

probably the best seminar title ever

Dear all

Tomorrow, Wednesday (15.15 in Häggsalen), Peter Holdsworth will give a talk on:

"My (almost) successful search for a spin-liquid, spin-gas phase
transition"

this is a ccd image of the HeNe alignment laser. the hole in the multilayer mirror is the dark spot in centre. to the upper right is the saturated spot from the HeNe. the HeNe did not make it through both the round aperture in the sheet metal plate at the same time as the hole in the multilayer mirror. this was done in vacuum. today we will continue work in air, to turn the experiment the needed 2°.

apertures & samples into place

now apertures and samples have been put into vacuum. photo 1 is taken from the horizontal plane, 45° from where the fel beam comes.
photo 2 is taken from above.
however, we have not mounted Al filters to the ccd. two of the very precious 140nm thin films cracked when exposed to air...

henrys update from 5am

We've made some steps forward and some back. We successfully installed the insert into the Moller chamber, after disassembly of Christoph's apparatus. We had decided to leave the mirror at the 0 degree position, to be able to align it to the beam (tolerance is 0.5 mm mirror displacement before you run off the multilayer reflectivity, and due to changes in beamline -- see below). We haven't yet installed samples, apertures, or filter.

Pumping takes a couple of hours to get to 5x10^-7 (setpoint to open to beam), which seems to be about the same rate as earlier pumping tests. We had some trouble with interlocks and finally solved that. The beamline setup has changed, with the addition of the wavefront sensor out the back of the chamber. This could in principle be used to align the mirror but not quite operational as yet. However, this prevents us from using the transit to align. Another change is that the valve upstream of the chamber is no longer a window valve, so we only get HeNe when pumped. Or we could have vented part of the beamline, but that would require someone to come on Monday to reapprove the beamline. So we decided to use the photodiode and CCD to see the HeNe, with the system in vacuum.

There are problems with this approach. The HeNe is so intense that even the scattered light in the chamber saturates the CCD. The photodiode signal didn't make sense, but we realized at about 3 am this morning that we in fact installed the insert on the wrong bolt pattern. When we installed it, it looked about right and we had aligned two black marker marks that were on the chamber flange and our flange. But by stringing up a wire along the beam path it is obvious we need to rotate by one hole.

Sebastien's cooling was tested -- we get down to about -35 degrees, but not enough N2 flow to go lower. He will add more coils to the coil.

In the morning Magnus and Calle will look for a 1 micron thick Al foil and attach it to the aperture plate, so that we have some apertures with 1% attenuation, if need be.

Currently venting the chamber.

We need someone to talk to Elke in the morning to convince her to let us use the wavefront sensor.

Vented, more later.

Opened -- looks like the right bolt pattern after all. Just that photodiode is off-center (I think we knew that actually). Taking the opportunity to install the fibers to the attocubes.

to do-list

0. check the pressure to see if the new fiber feedthrough is OK.
1. find or buy from the store a 6" viewport flange so that we can look down from the top when pumped (or smaller viewport onto a 6" to 4" reducer and use the 4" viewport that was removed from the side to put on the mass spec. The 4" viewport flange is on Christoph's table around the back, could ask him to borrow it) (Magnus, Calle)
2. 1 micron Al foil (Magnus, Calle)
3. Sort out wavefront sensor with Elke. We can take responsibility for trying to align it -- we have enough people! We need at least to use it for beam intensity for alignment, and for difference wavefront measurements (sample - no-sample) at the most. (Janos, Anton)
4. Test attocube fiber feedback (Anton)
5. Test shutter trigger (Anton, Sebastien)
6. Test CCD cooling with more coils (Sebastien)
7. Find out if HeNe can be attenuated
8. Construct protector for fibers coming out of feedthrough -- could be long threaded rods bolted to the free flange holes.
9. Figure out how to align beam -- options:
use wavefront sensor (as intensity monitor)
install a window valve where we were meant to have one
vent beamline section upstream of chamber
use FEL light with gas attenuator + foil attenuator

chamber motors, online control

x-terminal
> cd on_line (program must be started in on_line)
-confirm all error messages...
-at online prompt start tki (toolkit interface)
in tki command line you can move motors with command:
mov motX Y
(X motor number 1: hor perp. to beam, number 2: vertical)
(Y displacement in nm: christoph ostedt calibrated that)
hit refresh to show actual motor positions

trouble shooting
1) reset crate "wiener"
2) reset motors (back of rack)
3) restart online
4) restart computer

chamber motors

x(ver): OJ (original alignment with HeNe): green line on top of metal paddle.
y(hor): OJ to the left of the metal paddle.
z(beam): OJ to the right of metal paddle, red line on focus determined by the möllers (see post: focal length 15mm).

two ways to drive the motors: 1) controller, 2) online program.
1) controller: prog.6, H speed.
2) online program: linux, i will talk to julia medved tomorrow, since this (hasylab) program is bugging now.

-powerful motors, keep track of bellows, cables, positioning paddles etc...
-keep serial cables connected to keep the motors with voltage, so they will not lose position.

vacuum checklist

venting: break interlock
1. beamline: close beamstop, then valves, on doocs
2. nitrogen flow for venting ok?
3. high voltages etc in chamber off?
4. break interlock by turning off the tmp, make sure to turn it on again!
5. wait until >1000mbar on the gauge controller

pumping down: bridge interlock
1. rough down chamber slowly by external pump
2. close and LOCK! external pump
3. bridge interlock:
3a. roughing pump starts
3b. valves open (clacclacclac, few secs)
3c. tmp spin up
4. re-activate interlock (after tmp running)
5. on interlock controller: 1,2,9,10,11 pumpen etc on (upper lights green)?
6. on interlock controller: 6,7 pressure gauges: bridge off only when setpoint reached
7. pressure should drop within 5 minutes to 10-5mbar

-tcp380 x3 on spin up speed 2 min 1000Hz 0.5A (not more than 1A)
-tcp600 x1 on spin up speed 5 min 650Hz 2A (not more than 3A)

interlock basics
gauges 1,2 (pfeiffer)->
gauge controller (pfeiffer)
2 interlock signals: 1-> interlock controller; 2-> ring connection to doocs

------| interlock (pumps ok?) |-----------| pressure gauges ok? |---V
|
doocs----------------------------------------------------------------------^

mechanical pumps
-white cable: interlock
-valves: white cable interlock
-white interlock cables serial in
a) Umschaltbox für Ventile (valves)
b) Umschaltbox für VorVacuumPumpe (mechanical pumps)
-small edwards pump: gauge controlled by pressure air & 24V
-other pumps 230V
-white power strip (3x, red TU) controlled by interlock for valves (for this use ONLY)

interlock comment:
the pressure gauge interlock in our system is only to protect the pumps, therefore the setpoint is rather high.
the beamline pressure interlock is to protect the beamline, therefore the setpoint is much lower (5e-7 mbar).

personpower schedule

we need people for 24h at the experiment, even though we only have beam at night (7pm-7am). and too many people around the experiment is hmm. so here is a plan not to be taken too literally, especially the first days. 5pm daily meeting around the beamline.
00 02 04 06 08 10 12 14 16 18 20 22 24
xxxxxxxxxxxx_________________xxxxxxxxx fel
xxxxx________________xxxxxxxxxxxxxxxxx anton, sebastien, stefano
xxxxxxxxxxxx______________xxxxxxxxxxxx henry, janos, gösta
_______xxxxxxxxxxxxxxxxxxxxxxxxxx_____ florian, magnus, calle
xxxxxxxxxxxxxx________________________ mike

mie scattering simulations

these are simulations i got from magnus.

switching between experiments on monday

on sunday night at 7pm, the möllers will have had their last photon for this time. (they will have beam again on the 10th of february, after our beamtime.) they will empty their chamber on sunday night, it will take a few hours. they want manpower from us, anyone volunteering? the möllers will then leave for a well-deserved rest in berlin on monday. christoph bostedt will leave his mobile on over the first few nights of beamtime(...).
we will try to put in things on sunday night, but most probably we will do the heavy work on monday day.
notes from the meeting:
-the HeNe (optical alignment laser) and the fel are VERY correlated.
-the gas monitor detectors (GMD, for fel intensity monitoring) work well, and so does -pointing stability is 50um.
-focus is 30um.
-when the fel works well, the 2nd harmonic at 16nm is about 1% of the total intensity. otherwise a bit less, but more than 0.1%.
-the attenuator (a gas cell), which gets stable on a 5 minutes basis. however, when the beam is attenuated down to promille, the GMD does not give feedback to the operators, and they have more problems maintaining good fel.

LN2 cooling of the camera

magnus and sebastien have made the liquid nitrogen (LN2) cooling so that the probe shows -50°C without the heating. the heating can easily compensate to the desired -40°C. which is ok. we will not test the cooling connected to the camera in air, which would cause a lot of adsorption of dust. so unfortunately, we will only be checking the full setup on monday in situ.

meeting about the new chamber

one of the purposes of this beamtime is to set the parameters for the uppsala chamber which will replace the möller chamber (picture). we should have a scheduled meeting here in hamburg. the date should be next week, then we will have experience with our setup in the möller chamber, and most people will be here.
list of issues:
1. kind of experiments?
a) scattering
b) electron/mass/fluorecence spectroscopy
on
c) deposited samples
d) solid-state samples
e) free molecules
2. experience regarding this beamtime?
3. gantt chart

scattering experiment on nanoparticles at ALS

vuv scattering experiments on spherical silica nanoparticles (100-240nm). the optical properties are probed by vuv radiation (155 and 83nm).

paper

fiber cables: good news

stefano tested all the fibers+grating yesterday night. the signal is good (cleaner for sample x-y). me and sebastien have now glued the cables through the flange with torrseal (an uhv-compartible glue). it will dry until tonight.

inspiration for our new chamber

some call it the death star. uwe beckers chamber is a superstar here, possibly the only candidate to compete with the alu foil as a first question from outsiders.

people here now

the group is expanding: now anton barty, stefano marchesini, henry benner, sebastien boutet, magnus bergh, janos hajdu, dick lee and me are here.

fiber cables

the fiber cables for the reading of the moving of the attocube motors have now been successfully been terminated by professional external help. the ir signal goes through properly.

annual users meeting

today was the vuv-fel user meeting. some experiments start to show results which are paperable. and the time schedule for the next few years was presented. old users have to send in proposals until the 1st of april for beamtime until march -07. elke plönjes from the staff put it: "the board will have to decide how to place the six overbooked weeks". i.e. all experiments which are in will continue to be in until march -07, almost nothing will change with respect to relative beamtime weight. new experiments can send a letter of intent until april 1st this year, to be evaluated, and proposals for the new experiments will have to be sent in by september 1st this year. they will probably first get beamtime in 2008. the users roadmap is:
beamtimes -06: may, july, october-november, and -07 february. the facility roadmap is: july: lasing at 12nm, september: variation of wavelength between shifts, november: long bunch trains. shutdown march 2007, which will last for many months. after that, the hardware will be in place for achieving 6nm. users will possibly get beamtime in 2008, although there is no schedule after march 2007.

credit to my master photographer magnus.

focal length 15mm

the möller group have made a rough estimate of the focal length on beamline (bl) 2, observing the ratio of Ar++ vs Ar+ (which has a non-linear response) in an atomic beam vs beam axis. the rayleigh length was determined to be about 15mm.

amapi

möller

the möllers are successful, which is good for all of us (i.e. we do not have to compensate them for bad beamtime). they have already changed to the second experiment (from mass spectroscopy to photoelectrons).

fel status

the beam is stable. the pulse energy is 2+ uJ. 5Hz; 32nm, single-ubunch mode.

attocube assistance

our main concern at present is the controlling of the attocube motors, which will position our samples and aperture.

the labview software we were given was an alfaversion. anton is working on that. and the optical fibers, which give info about the movement of the attocube give a poor signal. tomorrow morning we will have a optical fiber-setup through a flange without feedthroughs, but with a hole-solution, which hopefully will make an end to the fiber signal problem.

we had hoped for support from attocube, but:
we talked to christoph boedefeld from attocube. he has an appointment in munich on friday, so he will not be able to come to hamburg then. we agreed that we should try to fix things on the phone, we got his mobile, so we can reach him on the weekend.

beamtime preparation pictures

here is the setup of our mie scattering experiment, the pictures are taken today.

fel beamtime

möller group happy, although there is no beam at present. we have a problem with the attocube, hopefully the fibers, which we will get tomorrow, will make things better.