 Thu Jul 6 15:26:39 2023, JM, Leak update 
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The leak on the actuator arm bellows has been attempted to be sealed using UHV vacuum seal spray. The spray had the opposite to the desired effect and
the leak rate increased. When spraying with helium the leak rate had increased to 1e-9 mbar l/s. After lunch a second application of the vacuum seal spray
was attempted, however the leak was not sealed. The base leak rate had also increased to the 1e-10 level up from in the morning and yesterday. With the |
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Wed Jul 5 19:27:13 2023, JM, Pump down and leak test
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CARME and the interaction chamber have been pumping for ~26 hours, P=4.15e-7 mbar, attached figures show the current pump down plot in comparison to
the two previous pumpdowns in the last 2 weeks and the pump down with the bare chamber in 2020. The gradient of the pressure reduction appears to be improving
for each pump down, either due to conditioning of the chamber or the reduction in leaks. |
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Tue Jul 4 17:08:08 2023, JM, Leak test and venting
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This morning the pressure achieved was 1.44E-7 mbar. Leak testing showed an overall leak rate of 1.5E-10 mbar l/s, this is below the previous leak rate
but still significantly above the leak rate from elog 141 of the CARME chamber on its own. Spraying helium, a leak is visible on the VAT gate valve on
the interaction chamber (inside of the ring). The leak rate increases to ~2.3E-10 mbar l/s. No increase in the leak rate was observed elsewhere on CARME |
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Mon Jun 26 14:49:05 2023, JM, TD, CARME vented
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26/06/23
This morning the pressure was 4e-7 mbar. The bolts on the windows and the large flange on the bottom of the interaction chamber were tightend.
No leak was present on the windows following tightening. However, the leak on the rotatable flange, although decreased in magnitude, was still in the 1e-9 |
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Sun Jun 25 14:30:06 2023, JM, TD, Motors bias test
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The motors were moved using the pneumatic only, in and out for several cycles to gauge the effect on the vacuum. For the left arm no change in pressure
was observed. For the right arm a small increase of 0.04e-7 mbar was observed which was quickly reduced by the turbo.
The detectors were then biased to see if movement had any effect on the leakage current (large effects were observed in 2021 beamtime). Movement |
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Sun Jun 25 10:08:30 2023, JM, TD, Pump-down
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23/06/23
Pumpdown started with the scroll pump 17:15 . The turbo-pump was started 17:55. Gate valve was closed and the turbo turned of at 19:20 due to
no working fan on the turbo. |
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Sun Jun 25 09:41:06 2023, JM, TD, Normal turbo-pump operation 6x
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| Attached are images showing the messages for normal turbo-pump operation |
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Sat Jun 24 10:38:42 2023, JM, TD, Section 9 closed, begin pumping
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23/06/23
The CARME chamber and interaction chamber were connected and section 9 has been fully closed. New valves have been installed on the interaction
chamber, in addition to new diamond windows. A leak cart has been connected to the backing line of CARME. Before begining the pumpdown, the manual valve |
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Thu Jun 22 18:58:02 2023, JM, TD, Slide back onto ring
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The wire seal has been tightend further to 160 Nm. Open neg feed-through flange has also been fully tightend.
The CARME chamber was then slid back onto the aluminium frame on the ring. Two carriages were damaged during the sliding process, which have
now been replaced. Carriages were replaced by lifting one end of the upper frame section using the crane by only ~1mm. This was sufficient to slide out |
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Wed Jun 21 18:47:36 2023, JM, TD, Closing CARME
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Internal CARME installations complete.
New strain reliefs (flange side) installed on each cable harness.
2x sets of SAES UHV1400 NEG pumps installed and connected
to 2x power feed-through flanges -> continuity checked OK -> 3x UHV1400 modules gives a resistance of 7.4 Ohms, 2x UHV1400 modules gives resistance |
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Fri May 26 09:08:06 2023, JM, CB, Detector movement
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Hopefully we will not be opening the chamber for quite some time so find attached images of all four installed detectors and a video of them both moving
into the beam axis for future reference |
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Fri May 26 08:53:54 2023, JM, CB, Strain reliefs (flange side) installed
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Strain reliefs on the flange side of the cable harness have been installed for two detectors (top right and bottom right detectors).
We require the strain relief parts from edinburgh in order to install strain reliefs for the left two detectors.
Find attached images for the strain relief installed and a video of the clamped cables during a movement cycle. |
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Wed May 24 09:54:56 2023, JM, CB, Maximum detector positions 9x
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The detectors were moved into the beam axis using the motors to check the maximum distance they can be moved in without collision with one another.
Movement of both pneumatic motors results in a separation of ~ 4 cm between the detectors.
The servo motors for left and right were each moved in by 1 cm -> results in separation of 2 cm between the detectors |
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Wed May 24 08:35:12 2023, JM, CB, Strain reliefs (detector side) installed
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The new MACOR strain reliefs on the (detector side) have been installed. See attached photos
The two pieces of MACOR are not fully closed but we are confident that the kapton wires are sufficiently clamped.
In order for the strain reliefs to be installed in the correct poisition, two nuts on the jacking plate of the cable harness had to be removed. |
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Mon May 15 07:34:22 2023, TD, Monday 15 May
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08.35 DSSSD#3 bias -149.95V leakage current -6.418uA temperature +19.6 deg C ( https://web-docs.gsi.de/~lestinsk/tempplot.php )
DSSSD#3 bias OFF |
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Sun May 14 11:55:12 2023, TD, Sunday 14 May
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12.44 DSSSD#3 bias -149.95V leakage current -6.448uA temperature +19.7 deg C ( https://web-docs.gsi.de/~lestinsk/tempplot.php )
CRYRING cave lights ON - leakage current measurements @ 60s intervals
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Sat May 13 11:34:25 2023, TD, RSS, Saturday 13 May
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12.34 DSSSD#3 bias -149.95V leakage current -6.763uA temperature +21.2 deg C ( https://web-docs.gsi.de/~lestinsk/tempplot.php )
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Fri May 12 16:24:20 2023, RSS, TD, V-I test 8x
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Since yesterday evening, the bottom right detector was at -150 V. In the morning, the current was quite stable ~ 6.77 uA. The bias was switched off,
the foils opened, both of the detector arms were moved in and out three times, and the chamber was tightly covered again. A negative bias voltage was applied
from 0 to 150 V in steps of 10 V one by one to all four detectors, and the V-I results can be seen in Attachments 1-4. All detectors seem to be |
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Thu May 11 21:22:54 2023, RSS, TD, V-I test 7x
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Today, the foil was opened, the pins on the bottom right detector were checked and looked fine, the right-hand arm was moved a bit in and then out, and
the foil was tightly closed again. The negative bias voltage was applied from 0 to 50 V in steps of 10 V. During the measurement, the lights in the cave
were switched off to ensure no leakage current from the light*. The results are shown in Attachment 1. To condition the detector, it was left at a negative |
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Wed May 10 19:06:18 2023, RSS, TD, V-I test
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To test the detectors, adaptors were installed on the feed through flanges. A negative bias voltage was applied in steps of 10 V from 0 to 150 V. The
V-I plots are attached for the four detectors. Three detectors - top right, top left, and bottom left (in the direction of the beam) - are fine. For the
bottom right detector (in the direction of the beam), the current was fluctuating and was considerably high (1st test). The adaptors connecting to this |