40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  ATF eLog, Page 1 of 55  Not logged in ELOG logo
ID Date Author Type Categorydown Subject
  287   Thu Aug 27 20:00:59 2009 AlastairLab Infrastructurestuff happensLenses

I ordered some lenses for the lens kit.

  288   Thu Aug 27 21:40:20 2009 (not) AlastairLab Infrastructurestuff happensLenses

Quote:

I ordered some lenses for the lens kit.

 What focal lengths/coatings

  289   Fri Aug 28 10:26:12 2009 AlastairLab Infrastructurestuff happensLenses

Quote:

Quote:

I ordered some lenses for the lens kit.

 What focal lengths/coatings

I chased this up this morning.  Even though I made the order directly through techmart (not as a spot buy) Newport have not received it.  I'll put it in again.  The lenses will have the AR18 anti reflection coating for 1000-1550nm.

I'm ordering two each of the following:

KPX103 - f=175

KPX106 - f=200

KPX109 - f=250

KPX112 - f=300

KPX115 - f=400

KPX118 - f=500

KPX121 - f=700

KPX124 - f=1000

I'm ordering one each of the following:

KPX100 - f=150

KPX097 - f=125

KPX094 - f=100

KPX091 - f=88.3

KPX088 - f=75.6

KPX085 - f=62.9

KPX082 - f=50.2

KPC037 - f=-75

KPC034 - f=-100

KPC028 - f=-200

  290   Fri Aug 28 10:52:35 2009 AlastairLab Infrastructurestuff happensLenses

Quote:

Quote:

Quote:

I ordered some lenses for the lens kit.

 What focal lengths/coatings

I chased this up this morning.  Even though I made the order directly through techmart (not as a spot buy) Newport have not received it.  I'll put it in again.  The lenses will have the AR18 anti reflection coating for 1000-1550nm.

I'm ordering two each of the following:

KPX103 - f=175

KPX106 - f=200

KPX109 - f=250

KPX112 - f=300

KPX115 - f=400

KPX118 - f=500

KPX121 - f=700

KPX124 - f=1000

I'm ordering one each of the following:

KPX100 - f=150

KPX097 - f=125

KPX094 - f=100

KPX091 - f=88.3

KPX088 - f=75.6

KPX085 - f=62.9

KPX082 - f=50.2

KPC037 - f=-75

KPC034 - f=-100

KPC028 - f=-200

 Gina has checked through the PO and Newport should definitely have received it, but they claim they did not.  This is the third time that I know of recently that we've had trouble with ordering this way from Newport.

---  The new order has now been put through and has arrived at Newport ---

  291   Fri Aug 28 12:26:14 2009 DmassLab Infrastructurestuff happensLenses

I thought we wanted the straight up 1064 only coating on these (AR.33)?

According to Newport:

  • Ravg <0.5% for AR.18
  •  Ravg <0.25% for AR.33

 

  292   Fri Aug 28 12:39:00 2009 AlastairLab Infrastructurestuff happensLenses

Quote:

I thought we wanted the straight up 1064 only coating on these (AR.33)?

According to Newport:

  • Ravg <0.5% for AR.18
  •  Ravg <0.25% for AR.33

 

 That would probably be better, but I'm just replacing like with like in the lens kit just now.

  356   Mon Sep 28 20:40:53 2009 AidanMiscstuff happensPlease do not leave the permanent marker by the whiteboard ...
  367   Wed Oct 7 02:47:41 2009 AidanMiscstuff happensDigital camera is in my office
  476   Wed Dec 9 11:53:42 2009 FrankLaserstuff happenslaser data unavailable since 1 week

the laser data is not available since i left last week. Can some plz check the IBM laptop computer sitting in the rack on top of the HV power supply. plz reboot/turn it on and boot windows (not linux). if you don't choose it from the boot menu while booting it will be running linux by default.... thanks

  681   Thu Mar 18 15:59:46 2010 FrankLaserstuff happensAmplifier service

We tried to adjust the pump light in xtal 1, since it seems to be a little too high - no success, so we aligned it (and the mirror set in front of the amplifier) back.

Note: The original pump current for the diodes was 48 A (so, we set it to this value).

The original temperatures of the pump diodes were:

D1: 20 degC

D2: 20 degC (was: 23.8, so we set it back, since then the output power slightly increased)

D3: 24 degC

D4: 25 degC

The observed output power downstream the PBSs (3) and waveplates (3 HWP + 1 QWP) was 29.5 W.

  751   Thu May 6 19:45:10 2010 DmassLaserstuff happensChalkboard
Attachment 1: Discipline.gif
Discipline.gif
  788   Wed May 26 17:13:07 2010 AidanLab Infrastructurestuff happensMoved a New Focus 9071 4-axis stage to 40m for doubling
  805   Tue Jun 8 10:35:16 2010 AidanMiscstuff happensMoved some equipment to 40m

I've taken the following items to the 40m.

  1. 40MHz AOM
  2. Thorlabs Broadband EOM
  3. 2x New Focus 9071 4-axis stages
  4. ZHL-1A RF amplifier
  5. ZHL-2A RF amplifier

They're all marked "Adhikari Lab".

  970   Tue Aug 24 02:38:42 2010 ZachLaserstuff happensThorLabs power meter head appears damaged

 While I was using the ThorLabs power meter today, I noticed that the slide-out filter appears to have a small bump on it near the center. I don't think I dinged it on anything, and it doesn't even really look like the result of a ding. It's tough to tell from the picture, but the bump is raised up, and not dented in. Has anyone seen this before (on our unit or elsewhere)?

PM_head_damage.jpg

  971   Tue Aug 24 03:00:20 2010 DmassLaserstuff happensThorLabs power meter head appears damaged

Someone burned it.

  999   Sun Aug 29 23:04:17 2010 ranaLab Infrastructurestuff happenslab cleanup

The lab has turned into a pit again. Please clean up your stuff. There cannot be tools lying around or drinks or water bottles or used booties or scraps of paper.

Empty the trashes, change the sticky mats, etc.

I also power cycled the router. This router was just a bad choice - I suggest we just get the 24-port router which the 40m is using. I'll ask Joe if it will work.

  1027   Thu Sep 9 00:22:14 2010 DmassElectronicsstuff happensNewport 3040 fukt?

I spent the better half of the day trying to debug the 3040 - I returned to an old working hardware setup with some extra 100 Ohm platinum RTDs, but I couldn't get one of the 3040's to read it in the right way. Resistance is "err", and nothing I seem to do or plug in seems to change it.

  • I checked the cabling to the 3040 - it was fine (no open connections, or mysterious shorts)
  • I checked the software limits and tried to make them as large as possible
  • I checked the sensor type and its coefficients
  • I switched the RTDs between 3040's, the failure followed the 3040
  • I did the onboard calibration for the RTD with a 100 Ohm thin film, as per the manuals instructions
  • I calibrated out the RTDs leads with a short, as per the manuals instructions.
  • I restored the machine to an earlier state (presumably from when it was still @ MIT), and repeated the above - still nothing.

Back story which may or may not be pertinent (guesses at possible damage here).

  • I snapped off the lead from my 100 Ohm RTD on my oven a few days ago.
  • I tried to use a 1000 kOhm RTD which I already had affixed to the oven as a spare, but the 3040 doesn't seem to know about these -
  • I had a 1 kOhm RTD in with the coefficients from a 100 Ohm for a bit (as it wouldn't let me switch them)
  • It seems unlikely that the having wrong sensor type could damage your 3040, as you have to cycle through types with the ipod-esque wheel to select the right one.

I then tried to use an NTC thermistor as the sensor, since I had some already wired up.

  • The manual quoted +/- ranges for the Steinhart-Hart coefficients for thermistors, which seems to imply that NTC and PTC are O.K to use
  • I pulled the NTC Steinhart-Hart coefficients from a quick matlab fit
  • When I tried to use them,the 3040 told me they were illegal and forced the coefficients back to their default positive values

I abandoned this and soldered some connectors on some spare 100 Ohm RTDs, of the exact same type which is working on the other 3040. I then experienced the problems from the first list...

I hope there is something stupid that I am somehow missing, otherwise I either have to skip the last couple measurements for the paper, or wait wait wait for a replacement / refurb / homestyle debugging of the 3040 - I will try to recruit a fresh set of eyes tomorrow to look at this.

  1028   Thu Sep 9 05:17:19 2010 DmassElectronicsstuff happensWho cares!

I switched to using one newport to control both ovens (one has no sensor, is just getting the actuation signal from teh other).

I was able to get the Mach Zehnder back and running.

Leaving it running overnight with with its calibration line on and HEPA off...I also have AC coupled thermistors on each oven being recorded by the DAQ now, so this should tell me exactly how "not ok" it is to use one controller for two ovens, which comes down to how correlated the low frequency temperature changes are inside the box.

Next up - HEPA on / off test, and comparison of 1 controller phase noise spectrum with 2 controller phase noise spectrum.

  1033   Thu Sep 9 18:31:48 2010 DmassElectronicsstuff happensWho cares!

I switched both HEPAs on to "low" and relocked the PMC at 6:40 PM today.

8:07 PM - both HEPAs turned to "med"

NTC Thermistor SR560 Gain set to 10 (was overloading @ 20).

NTC Thermistor mode set to "A-B" on one of the 560s with nothing hooked into B. Unknown if this makes it fluctuate or not. Channel is "daq1-gen4"

  1035   Thu Sep 9 21:12:50 2010 DmassElectronicsstuff happensRouter Crashed again?

Router crashed? Can't get channel list.

- Had Tara restart router, still can't get channel list. Was fine this afternoon.

  1036   Thu Sep 9 21:45:26 2010 DmassElectronicsstuff happensRouter Crashed again?

Quote:

Router crashed? Can't get channel list.

- Had Tara restart router, still can't get channel list. Was fine this afternoon.

 nds and daqd both seem to be running on fb0.

  1037   Thu Sep 9 21:56:29 2010 DmassElectronicsstuff happensCan't get data from 40m network?

Get_data worked without hitch when I used a vpn caltech connection. I think I am on the 40m ligo network (131.215...). I toggled on and off a couple times to check, and it only worked with the VPN on.

  1038   Thu Sep 9 21:57:37 2010 FrankElectronicsstuff happensRouter Crashed again?

looks like you have to work in the lab instead of sitting on the couch 
It's working if you try to get data from there... Or try to tunnel port 8088 through ssh, that should work too. That's the way i usually forward any services which are not accessible from outside.

Time to replace the router....

Quote:

Quote:

Router crashed? Can't get channel list.

- Had Tara restart router, still can't get channel list. Was fine this afternoon.

 nds and daqd both seem to be running on fb0.

  1039   Thu Sep 9 22:38:06 2010 ZachElectronicsstuff happensRouter Crashed again?

I noticed yesterday that although mDV was working again (I could get data by supplying the channel names manually into get_data), ligoDV could not obtain channel lists for C2 as it could before. Not sure if this is related.

Quote:

looks like you have to work in the lab instead of sitting on the couch 
It's working if you try to get data from there... Or try to tunnel port 8088 through ssh, that should work too. That's the way i usually forward any services which are not accessible from outside.

Time to replace the router....

Quote:

Quote:

Router crashed? Can't get channel list.

- Had Tara restart router, still can't get channel list. Was fine this afternoon.

 nds and daqd both seem to be running on fb0.

 

  1041   Fri Sep 10 01:03:21 2010 DmassElectronicsstuff happensWho cares!

1:40-2:30 HEPA off, AC coupled temperature being written.

 

2:30 -> HEPA low.

 

  1042   Fri Sep 10 01:24:41 2010 DmassElectronicsstuff happensSR560 needed

One of the SR560's I was using to AC couple my nice new temperature sensors is...broken? It's output goes from tiny to railed with a 50 Ohm on the input when switching to a gain of 50. It takes a while to come down off the rail after reseting it. I don't trust its output.

I nicked what looked like a spare SR560 from the TCS lab. Settings when I turned it on were DC coupled, 3 Hz low pass single pole, gain = 20.

  1043   Fri Sep 10 16:32:32 2010 DmassElectronicsstuff happensWho cares!

Quote:

1:40-2:30 HEPA off, AC coupled temperature being written.

 

2:30 -> HEPA low.

 

 4:31-4:47 PM Fri - Noise test on DAQ_GEN4

4:49 - Noise Test on DAQ_GEN3

5:30 or so HEPA on low

9 PM HEPA to off

11 PM HEPA to low

1AM HEPA off

  1229   Mon Dec 20 00:49:55 2010 ranaMiscstuff happenstrivia

KEvsMOMENTUM.png

from the Wikipedia article on Dispersion.

  1353   Tue Mar 15 00:30:46 2011 ZachLaserstuff happensrecent gyro plots are LIES

 Due to an error somewhere in the front end code, the channel that should have been "PLL_ACT" was actually receiving the "CCW_REFL_DC" signal. All data and plots for noise in the PLL actuation readout are absolutely wrong.

Having made sure that I was monitoring the right damn channel, I observe that the PLL actuation noise is once again the same as the AOM actuation signal. This puts us at ~2 x 10-5 (rad/s)/rHz at our most lenient requirement frequency of 200 mHz, or roughly 2700x where we need to be. I currently have and all enclosures shut and all boost engaged (2 for the primary loop and 1 for the secondary). Changing the number of boosts does not affect the low frequency noise relationship between AOM_ACT and PLL_ACT. The secondary loop has >60 dB of OL gain below 50 Hz, so if changing the boosts does not affect the noise then it means that either 1) the same noise that couples into the AOM signal is coupling in independently into the PLL loop and causing the same noise level despite the suppression from the secondary loop, or b) we don't understand how it really works. I cannot see how differential IO noise is not suppressed by the secondary loop gain as measured in the PLL actuation; this just doesn't make sense.

I'm not really sure what else to do. We have isolated all the optics from the open air, and ensured that the locking loops have a pretty solid amount of gain (the secondary loop gain is not astronomical, but it's enough that we should see something) and yet we can't reduce the noise at the transmitted port. The addition of the vacuum system and custom PDs has amounted to a factor of ~5 better noise. Big whoop.

Also, the chamber pressure is now up to about 1.7 torr (no factors of 10 here).

  1354   Tue Mar 15 12:34:33 2011 AlastairLaserstuff happensrecent gyro plots are LIES

 

 Did you change anything since then in the front-end code?  I'm looking at it right now, and it looks like a physical wiring problem not the front-end code.

  1356   Thu Mar 17 15:09:18 2011 AidanMiscstuff happensLVC Lab Tour

Visitors to the lab ...

Attachment 1: P1000411.JPG
P1000411.JPG
Attachment 2: P1000412.JPG
P1000412.JPG
Attachment 3: P1000413.JPG
P1000413.JPG
  1553   Tue Oct 18 16:38:27 2011 ZachMiscstuff happensATF floppy drive is missing

 Please bring it back---sharing is caring.

  1883   Thu Jun 26 14:48:58 2014 ZachLaserstuff happensCalibration error ruins the day

A riddle: what, besides hard work and dedication, causes a noise reduction? A calibration error!

Despite that the calibration for the open-loop readout is actually very simple, I made an arithmetic error that completely nullifies the apparent recent improvement. The gyro is only as good (or as bad) as it used to be.

I am equal parts embarrassed and disappointed. I truly thought I had seen an improvement, since there were several things I seemed to have fixed that would account for roughly the same enhancement as I thought I saw.

  65   Tue Jul 22 18:43:06 2008 DmassComputingfubardigital control broken.
I tried to restore the hacked up oms control system via a series of escalating measures.

a) I ssh'ed into the FE computer (oms) and did "startoms"
-that seemed to run, but there were errors in the status window of screen "C2OMS_GDS_TP.adl" next to the red light FB0, of type 0x2001 if I recall correctly

b) I then tried to remake the oms FE code via the commands in Tobins elog entry
- make oms
- make install-daq-oms
- make install-oms
- make install-screens-oms
Nothing upon restarting the FE. No more error messages from the FB0 button now. possibly more broken than before.

c) Stefan and I then did a "sudo reboot" on oms, still nothing.

We found as the last line in the log file
/cvs/cds/caltech/target/c2oms/log.txt
"DAQ init failed -- exiting"

It appears that the daq no longer starts. I have sent Alex an email, and have tried calling him several times (have not gotten a pickup).
Daqconfig is also brokenish on the non FE computer (ws1). It gives "Error: can't read "y": no such variable" on startup, and will not display anything.

I will be working on getting Rich Abbott's PDH box up and running to lock the PMC while I twiddle my thumbs on the digital stuff.
  67   Fri Jul 25 14:59:24 2008 DmassComputingfubardigital control broken.

Quote:
I tried to restore the hacked up oms control system via a series of escalating measures.

a) I ssh'ed into the FE computer (oms) and did "startoms"
-that seemed to run, but there were errors in the status window of screen "C2OMS_GDS_TP.adl" next to the red light FB0, of type 0x2001 if I recall correctly

b) I then tried to remake the oms FE code via the commands in Tobins elog entry
- make oms
- make install-daq-oms
- make install-oms
- make install-screens-oms
Nothing upon restarting the FE. No more error messages from the FB0 button now. possibly more broken than before.

c) Stefan and I then did a "sudo reboot" on oms, still nothing.

We found as the last line in the log file
/cvs/cds/caltech/target/c2oms/log.txt
"DAQ init failed -- exiting"

It appears that the daq no longer starts. I have sent Alex an email, and have tried calling him several times (have not gotten a pickup).
Daqconfig is also brokenish on the non FE computer (ws1). It gives "Error: can't read "y": no such variable" on startup, and will not display anything.

I will be working on getting Rich Abbott's PDH box up and running to lock the PMC while I twiddle my thumbs on the digital stuff.


With the assistance of a benevolent Rob, the above problem was identified and fixed.

While looking at the logfile for C2oms, we found the script omsfe.rtl was crapping out because there were no daq channels set to acquire. We fixed this by manually setting one of the channels to acquire in C2oms.ini and uncommenting it. We then dropkicked the framebuilder by telneting in via
> telnet fb0 8087
and doing a shutdown. This should be equivalent to clicking the DAQ Reload button on the oms FE Diagnostic medm screens. This fixed the problem of the daq not starting, and we could get realtime data via dataviewer. To start recording it in the daq again, we just need to edit "C2oms.ini" to reflect which channels we are interested in recording.

It appears we can still not toggle channels to acquire via the daqconfig gui. I will worry about that more when I have a version control screens here that I am happy with, and harrass Alex.

We also found something interesting when we tried to interact with the system via DTT. It seemed that the system wanted there to be a link tpchanm1 pointing to tpchanC2, but the creation and subsequent annhilation of this link seemed to not effect the system. When we looked closer, the file we expected to define all the test points, /cvs/cds/caltech/chans/param/tpchn_C2.par, was full of objects for the atf system. The file that the system appears to actually get its definitions of these from was /cvs/cds/advLigo/build/omsepics/oms.par.

Rob says that this was an indication that something in the series of "make ___" commands is broken, as they should have overwritten this file at some point.
  192   Wed Jul 22 20:40:13 2009 AidanLab InfrastructurefubarFiling cabinet lock engaged ... with no key

This happened mysteriously and had absolutely nothing to with me. The fact that I was the last person to open the filing cabinet before this happened is circumstantial and beside the point.

Will get the lockshop onto this in the next couple of days. In the meantime, just try and exercise your clairvoyance.

  244   Mon Aug 10 20:14:11 2009 AidanLab InfrastructurefubarFiling cabinet lock engaged ... with no key

Quote:

This happened mysteriously and had absolutely nothing to with me. The fact that I was the last person to open the filing cabinet before this happened is circumstantial and beside the point.

Will get the lockshop onto this in the next couple of days. In the meantime, just try and exercise your clairvoyance.

 

 

Fixed! The key is now hanging in the second bay from the right above the main bench.

  470   Mon Dec 7 14:01:18 2009 AidanComputingfubarFront-end is down ...

I tried to make a change to the front-end in Simulink and compile it on fb0 - which is supposedly now our front-end machine. For some reason it won't build the .rtl file that is the front-end itself. When I tried to revert to the backed-up model I had the same problem. It doesn't look like anyone has tried to rebuild the front-end since late September and there have been some changes to the network since then.

I'm going to track down Alex and sort this out.

  520   Thu Jan 7 17:27:04 2010 ZachLab Infrastructurefubartip of the iceberg

Aidan and I began circling the holes in the ventilation system with Sharpies this afternoon, only to find that the situation was even worse than we thought before (which was already bad). Below is a picture of one particularly bad section (compare with Frank's previous post). We can continue to highlight each one, but by the time we are done the entire lab will look like this--maybe I should have chosen 'fugly'. The worst leaks are not the small ones that can be seen on the sides and bottom of the ducts, but rather the HUGE gaping holes on the top sections of nearly every joint in the system. I am fairly sure that even if we were to highlight each and every hole, we will not get PMA to fix each one. Rana suggests that we at least get them in to fix the largest ones for the time being.

00001.jpg

  565   Fri Jan 29 17:53:03 2010 DmassComputingfubarMental Computing Broken

I was attempting to replicate the pwelch command using the numerical recipes formula for the Welch's Periodogram PSD estimate. Koji helped me figure out that the calculation was missing a factor of bandwidth, and even though it said explicitly it was a PSD, it was a power spectrum. He also helped me figure out some stupid errors I was making in indexing.

I have recreated the algorithm now, and am going to use this, along with TFestimate to do frequency domain subtraction. I think this could still be a good thing even with the MZWino code, but it will be good to at least compare.

  574   Thu Feb 4 00:59:23 2010 ranaComputingfubarELOG restarted: no more .ps files

I restarted the ELOG on NODUS just now. Our attempt to set up error logging worked - it turns out ELOG was choking on the .ps file attachment.

So for the near future: NO MORE .PS files! Use PDF - move into the 20th century at least.

matlab can directly make either PNG or PDF files for you, you can also use various other conversion tools on the web.

Of course, it would be nice if nodus could handle .ps, but its a Solaris machine and I don't feel like debugging this. Eventually, we'll give him away and make the new nodus a Linux box, but that day is not today.

To restart the elog:  http://lhocds.ligo-wa.caltech.edu:8000/40m/How_To

  736   Wed Apr 28 09:24:01 2010 AidanComputingfubarelog craziness - test to try and crash elog

 - apparently PDFs work okay. Frank is reporting continual crashes from last night when uploading a graph of the particle counter in different formats from Firefox in Windows.

Attachment 1: 40m_figure_ETM.pdf
40m_figure_ETM.pdf
  1068   Mon Sep 20 13:41:33 2010 ranaComputingfubarrouter was down so I power cycled it
  1073   Mon Sep 20 22:47:27 2010 AlastairMiscfubarliso

 I added some instruction to the ATF internals/scripting bit of the wiki for installing liso.  Since it needs gnuplot and this requires all kinds of other stuff it seemed like a good plan to document it for future generations.

In short the message is simple.  If you're using a mac then you should install X-code from your OSX dvd and then install MacPorts.  Your life will be greatly enriched and future dealings with all things linux will be nicer.

  1115   Fri Oct 29 17:31:41 2010 AlastairLab InfrastructurefubarOld white board

RIP Old Whiteboard

I found the old white board and got a photo of the info before the goons who removed it can throw it away.

As a tribute to the old whiteboard, I think that Aidan in particular will appreciate this

 

Attachment 1: photo.JPG
photo.JPG
  1116   Sat Oct 30 14:09:20 2010 Curious GeorgeLab InfrastructurefubarOld white board

Quote:

RIP Old Whiteboard

I found the old white board and got a photo of the info before the goons who removed it can throw it away.

As a tribute to the old whiteboard, I think that Aidan in particular will appreciate this

 

 Why did we switch whiteboards?

Why would we let them throw this one away?

 

  1122   Mon Nov 1 16:35:15 2010 AlastairLab InfrastructurefubarOld white board

Quote:

Quote:

RIP Old Whiteboard

I found the old white board and got a photo of the info before the goons who removed it can throw it away.

As a tribute to the old whiteboard, I think that Aidan in particular will appreciate this

 

 Why did we switch whiteboards?

Why would we let them throw this one away?

 

 Don't ask me George, I have no idea.  We now have a huge door sized white board though, and a sort of fake wall covering up the door.  I'm just assuming that at some point the old one will be gone since it no longer has a wall to live on.  Any more questions?

  1328   Wed Mar 2 09:14:01 2011 ghostwriterMiscfubardump or optics lab?

100_1228.JPG

100_1229.JPG

100_1227.JPG

100_1226.JPG

100_1230.JPG

100_1228.JPG

  1334   Thu Mar 3 00:36:11 2011 ZachMiscfubardump or optics lab?

optics lab

 

lab_is_clean.png

Quote:

100_1228.JPG

100_1229.JPG

100_1227.JPG

100_1226.JPG

100_1230.JPG

100_1228.JPG

 

  1564   Wed Nov 9 00:39:52 2011 ZachLaserfubarWhat not to do to a dogclamp

This is what one of the stainless steel dogclamps looked like when I removed it from the vacuum chamber today. This is most likely from the improper configuration we have to use them in due to space constraints, but could also be as a result of improperly pitching them (by using the right counter-height). This is one reason I have opted to use the longer screws from now on.

busted_dc1.png busted_dc2.png

ELOG V3.1.3-