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New entries since:Wed Dec 31 16:00:00 1969
IDup Date Author Type Category Subject Text Attachments
  2779   Mon Jun 6 14:05:08 2022 AidanElectronicsPurchasesReturn me to WB265B: Location of Thorlabs S130C (silicon photodiode 5mW/500mW settings)[Aidan]

I bought a new photodiode for the
West Bridge Labs. It will be housed in the
 S130C_calibration.pdfIMG_9289.jpgIMG_9287.jpg 
  2780   Tue Jun 7 11:50:09 2022 RadhikaDailyProgressEmissivity estimationFastest cooldown + power budgets for 2" Si wafer cooldown in MegastatI've modeled the theoretical "best"
achievable configuration in Megastat, replacing
the flexible strap with a solid copper element,
 wafer_cooldown_model_ideal.pdfpower_budget_ideal.pdf 
  2781   Wed Jun 8 12:15:06 2022 RadhikaDailyProgressEmissivity estimationMegastat cooldown - repainted inner shield aquadag, added aquadag foil to cold plateThe cryocooler was turned off 6/8 at 11am.   
  2782   Thu Jun 9 10:27:01 2022 RadhikaDailyProgress2um PhotodiodesPD testing plan in CAML lab[Aidan, Radhika]

On Tuesday 6/7 we met to discuss
next steps for getting PD testing up and
  
  2783   Thu Jun 9 10:42:26 2022 RadhikaDailyProgressEmissivity estimationMegastat cooldown - repainted inner shield aquadag, added aquadag foil to cold plateI encountered several puzzles in the
data from this cooldown (Attachment 1):

1. Due to residual challenges with
 MS_cooldown_2022-06-02_data.pdf 
  2784   Fri Jun 10 09:47:07 2022 RadhikaDailyProgressEmissivity estimationMegastat cooldown - repainted inner shield aquadag, added aquadag foil to cold plateI looked closer at the RTDs, and they are
all PT100s with the same resistance-temperature
curve [Attachment 1]. So we might need to
 hmfile_hash_88f68a98.png 
  2785   Fri Jun 10 16:23:04 2022 ranaDailyProgressEmissivity estimationMegastat cooldown - repainted inner shield aquadag, added aquadag foil to cold plateFrom the plot, it seems like the slop is
~50 Ohms / 120 K. So a difference of 5 K
corresponds to ~2 Ohms.
  
  2786   Tue Jun 21 10:35:15 2022 Clare NelleDailyProgressEmissivity estimationRTD Calibration RTD
Calibration Plan Developed on 16-06-2022:



  
  2787   Tue Jun 21 11:00:57 2022 RadhikaDailyProgressEmissivity estimationThermal conduction through ceramic ball bearingsHere I summarize the analysis of thermal
conduction through 3 ceramic ball bearings
supporting a test wafer in Megastat. I considered
 1-s2.0-S027288421100229X-gr4.jpgthermal_conductance_joints.pngwafer_cooldown_model_ball_bearings.pdf 
  2788   Thu Jun 23 11:56:21 2022 JCElectronicsGeneralEquipment[JC, Paco]

I took the Moku and iPad from QIL
over to 40m for PLL Measurement at the 40m.
  
  Draft   Mon Jun 27 10:56:23 2022 RadhikaDailyProgressEmissivity estimationSi wafer emissivity testingHere I analyze potential gains from using
LN2 to kick off a Megastat cooldown, and
transition to a cryocooler to cool under
  
  Draft   Mon Jun 27 10:59:04 2022 RadhikaDailyProgressEmissivity estimationSi wafer emissivity testingHere I analyze potential gains from using
LN2 to kick off a Megastat cooldown, and
transition to a cryocooler to cool under
 coldhead_vs_LN2.pdfthermal_transfer_rate_LN2.png 
  2791   Wed Jun 29 09:39:01 2022 Clare NelleDailyProgressEmissivity testingRTD Calibration Day 2[Radhika, Hiya, and Clare]

We debonded the RTDs from the chamber
using isopropanol and acetone, then soaked
 ice_bath_calibration.xlsx 
  2792   Tue Jul 5 11:58:01 2022 RadhikaDailyProgressEmissivity estimationGlass wafer cooldown with ceramic ball bearings[Radhika, Clare]

On Thursday 6/30 we worked towards
a cooldown with a glass wafer rested
 6x 
  2793   Tue Jul 5 17:40:14 2022 RadhikaDailyProgressEmissivity estimationGlass wafer cooldown with ceramic ball bearingsThe cryocooler was switched off on Tue
7/5 at 11:45am.
  
  2794   Thu Jul 14 18:15:41 2022 RadhikaDailyProgressEmissivity estimationUndoped Si wafer cooldown in Megastat[Stephen, Clare, Hiya, Radhika]

 IMG_3665.jpegIMG_3669.jpegIMG_3673.jpegIMG_3671.jpegIMG_3676.jpeg 
  2795   Mon Jul 18 11:02:50 2022 RadhikaDailyProgressEmissivity estimationPlan for this week[Stephen, Clare, Hiya, Radhika]

We started a cooldown on Thursday
with an undoped Si wafer in Megastat [
  
  2796   Wed Jul 20 15:55:41 2022 YehonathanUpdateWOPOInstalling 1811 PDs{Yehonathan, Paco}

We comfirmed that the DC ouput
of one of the 1811s is bad. We set out to
 Diabolo_Current_Power_at_PDs.png 
  2797   Fri Jul 29 14:27:43 2022 StephenDailyProgressCryo vacuum chamberProgress - Heaters, RTDs, MagliteUpdate to QIL/2795:


RTDs (Digi-key P/N 615-1123-ND)
brought to lab (see pic).
Heaters
  
  2798   Tue Aug 2 11:37:19 2022 RadhikaDailyProgressCryo vacuum chamberProgress - Heaters, RTDs, Maglite- RTD calibration with Clare scheduled
for Wed 8/3 morning.

- A heater will be bolted down
 IMG_3704.jpeg 
  2799   Thu Aug 4 10:16:04 2022 RadhikaDailyProgressEmissivity estimationMegastat RTD calibration[Clare, Radhika]

We performed a calibration procedure
on the newly ordered RTDs for Megastat, in
  
  2800   Tue Aug 23 22:23:06 2022 awadeUpdateWOPOInstalling 1811 PDsI recall at one point we had one of these
NF1811 with a broken power suply pin.  It
was from a limited production run with the
  
  2801   Fri Sep 9 12:10:29 2022 RadhikaDailyProgressCryo vacuum chamberProgress - Heaters, RTDs, MagliteI acquired internal tooth lock washers
to bolt down the ground wire to the aluminum
maglite body, but I soon recognized that
 IMG_3745.PNG 
  2802   Fri Sep 16 16:29:28 2022 RadhikaDailyProgressCryo vacuum chamberProgress - Heaters, RTDs, Maglite   IMG_3756.jpegIMG_3759.jpeg 
  2803   Wed Oct 19 18:46:49 2022 RadhikaDailyProgressEmissivity estimationAlumina samplesI'm documenting new 75x75mm alumina
strip samples brought to the QIL by Chris.
We have 5 strips 120um thick [Attachments
 6x 
  2804   Fri Oct 28 17:03:27 2022 RadhikaDailyProgressCryo vacuum chamberMegastat upgrade[Stephen, Radhika]

We met today to regroup and plan
out next steps for Megastat:
  
  2805   Fri Nov 4 18:08:27 2022 RadhikaDailyProgressEmissivity estimationAlumina samplesHere is a promising
epoxy for bonding an alumina strip to
a Si wafer (full data sheet in Attachment
 EP21TCHT-1.pdfScreen_Shot_2022-11-04_at_17.59.16.png 
  2806   Mon Nov 7 14:36:19 2022 RadhikaDailyProgressCryo vacuum chamberMegastat upgrade[Stephen, JC, Radhika] [WIP]

We met today to discuss the design
of the aluminum insert for the cold plate. [Diagram
 Measurements_11_7_22.PNG 
  2807   Mon Nov 7 15:20:30 2022 RadhikaSafetyLab MonitoringMinor flooding 11/7Today Koji noticed a water puddle along
the south wall of QIL (265B). Photos attached.
I lifted the cables from the main rack
 IMG_3875.jpegIMG_3879.jpegIMG_3876.jpeg 
  2808   Thu Nov 10 09:29:30 2022 JCSafetyLab MonitoringMinor flooding 11/7On Monday Nov 7, Koji found a puddle of
water in the beside the lab’s toolbox.
I contacted facilities to check this out
 0F498FED-37FF-4F95-9C94-89156AB628FC.jpg 
  2809   Tue Nov 22 13:33:05 2022 RadhikaDailyProgressEmissivity estimationAlumina samplesI exchanged emails with someone at MasterBond
about the thermal conductivity of this epoxy.
They said they do not expect the thermal
  
  2810   Sun Nov 27 15:13:42 2022 ranaDailyProgressEmissivity estimationAlumina samplesOn their web page (https://www.masterbond.com/properties/thermally-conductive-epoxy-adhesives),
they have one with Aluminum Nitride that's
twice as conductive. Is that useful to get?
  
  2811   Wed Nov 30 11:14:28 2022 RadhikaDailyProgressEmissivity estimationAl2O3 strip cooldown + bondingIn Attachments 1 and 2 I've modeled
the cooldowns of an undoped Si wafer (no
coating - assumed e=0.06), and of an alumina-coated
 Si_wafer_cooldown.pdfAlumina_varnished_wafer_cooldown.pdfcoating_e.png 
  2812   Wed Nov 30 14:23:11 2022 RadhikaDailyProgressEmissivity estimationAl2O3 strip cooldown + bondingToday I decided to go ahead and bond a
120um strip of Al2O3 to an undoped Si wafer.
I cleaned both samples and then applied varnish
 IMG_3943.jpgIMG_3944.jpgIMG_3946.jpeg 
  2813   Mon Dec 5 12:49:44 2022 aaronMiscEquipment transfervacuum gauge to cryo labWith Radhika's OK, I removed the Edwards
WRG-S vacuum gauge from the megastat to borrow
on the PSOMA cryostat until we receive our
 E00623CC-622E-44C6-B800-8B559334DF3C.jpeg0747FCD4-B844-4DC4-A225-A22F8C9C5E74.jpegC9637671-5104-448C-A6F2-425BD6065D10.jpeg5EA84A7A-4201-41E5-819C-395B96249E9E.jpeg 
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