John Wong wrote:

Nikita Bernier wrote: John Wong wrote: Nikita Bernier wrote: John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.  Friday, May 18, 2012, 13:15 Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr.  Continue ramping up...   Tuesday, May 22, 2012, 12:02 TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.      Tuesday, May 22, 2012, 12:13 Initiating the cool-down process at 5 A/min. See archive plots of the Target Heater (Attachment 1) and the Tube Heater (Attachment 2).  Tuesday, May 22, 2012, 15:24 TGHT/TBHT were ramped down to 0A.  The target has cooled for about 45 min.  All pumps and chillers are off.  The chamber has been vented.

 Monday, June 11, 2012, 12:20

After the re-conditioning, the target's end-caps vaporized.  This is something happened before (see elog entries below):

https://elog.triumf.ca/TIS/Evaporator_1/20

https://elog.triumf.ca/TIS/Evaporator_1/22

The caps were removed and yellow crystals were observed. (see attachment#1).

The D-caps will be inserted in both ends and will be re-conditioned again to see if the yellow crystals can be removed at high temperature.

John Wong wrote:

Nikita Bernier wrote: Nikita Bernier wrote: Thursday, April 05, 2012, 16:31 Target boat contains 6 BeO pellets : Sample,   Mass (g),   Thickness (mm),   Density (g/cm3) 1   1.2842,    5.406,        1.4647 2   1.2619,    5.150,        1.5108 3   1.2886,    5.316,        1.4946 4   1.2858,    5.310,        1.4931 5   1.3382,    5.520,        1.4948 6   1.3916,    5.650,        1.5187   Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick. **** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****    Tuesday, May 22, 2012, 16:44 Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.  Wednesday, May 23, 2012, 17:38 TGHT was stepped up to about 55A before the auto ramping was initiated.  The vacuum limit parameter was set for good vac at <4.0 e-5 Torr and bad vac at >5.0 e0-5 Torr.  The pressure is coming close to the trip limit (8.5 e-5 Torr) (see attachment 1: strip tool over the past 5 hours).  Changed the vacuum limit parameter:  good vac =3.0e-5 Torr, bad vac= 4.0e-5 Torr.   Saturday, May 26, 2012, 10:44 TGHT is auto ramping up smoothly as the pressure is regulating between 1e-5 to 4 e-5 torr.  (See attachment 2, past 21 hr) Sunday, May 27, 2012, 12:25   There could be a power bump  early this morning at 06:30hr, and tripped off the TGHT power supply (see attachment #3).  The computer in the cold lab was found to be off expectedly, so the alarm handler running on that computer was also shut off (*Need a UPS on this computer!)   Called the ISAC Ops, and  nothing about any power bump around that time was noticed.   Turned on TGHT p/s and set TGHT at 318A, local at 315A/4.58V.  TGHT has been running for about 10 mins.  Currently vac at 4.2e-7 Torr.   Sunday, May 27, 2012, 12:35 Initiating TGHT auto ramping...   Monday, May 28, 2012, 00:20 TGHT has reached to 600A and will remain at that current for the rest of the night.  The target oven temperature will be measured tomorrow. See attachment#4 for the striptool over the past 10hr.  Monday, May 28, 2012, 10:56 TGHT stayed at 600A for about 12 hours.  Pressure gradually came down to 7.6e-7 Torr. (See attachment #5).  At TGHT=600A, The target boat temperature was measured at 1400C (with the pyrometer), and the Ta-heat shield (1-layer) was at 1050C. [Note: These temperature measurements are very closed to the measurements with an empty LP target (with not heat shield), TGHT @ 600A = 1360C]. Monday, May 28, 2012, 11:04 Due to the water leak from the Evap2 chiller, the system has to be shut off for inspection.  TGHT was tapped down to 0A.  The target was cooled down for about 20min before the chiller was turned off. Will continue with the process after the problem is solved...

 Tuesday, May 29, 2012, 15:30

Evap2 was vented out and the pellets were taken out of the boat and examined.

The six pellets are cracked and have a greyish colour. The cracking is probably caused by the instant cooling and reheating when the system tripped on Sunday morning.

The light grey colour and white spots suggest that the sintering process was not completed and so the shrinkage cannot be determined.

A new batch of BeO pellets will have to be prepared and sintered in order to determine the dimensions of the final die.

Monday, May 28, 2012, 11:08

It was discovered this morning that the Evaporator #2 chiller was leaking water from the bottom (see attachment 1).  A puddle of water was formed and eventually found its way down to the Hotcell. 

The evaporator was running over the weekend for the BeO pellets process.  The TGHT is now off and the chiller will be inspected... 

Nikita Bernier wrote:

Nikita Bernier wrote: Thursday, April 05, 2012, 16:31 Target boat contains 6 BeO pellets : Sample,   Mass (g),   Thickness (mm),   Density (g/cm3) 1   1.2842,    5.406,        1.4647 2   1.2619,    5.150,        1.5108 3   1.2886,    5.316,        1.4946 4   1.2858,    5.310,        1.4931 5   1.3382,    5.520,        1.4948 6   1.3916,    5.650,        1.5187   Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick. **** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****    Tuesday, May 22, 2012, 16:44 Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.

 Wednesday, May 23, 2012, 17:38

TGHT was stepped up to about 55A before the auto ramping was initiated.  The vacuum limit parameter was set for good vac at <4.0 e-5 Torr and bad vac at >5.0 e0-5 Torr. 

The pressure is coming close to the trip limit (8.5 e-5 Torr) (see attachment 1: strip tool over the past 5 hours).  Changed the vacuum limit parameter:  good vac =3.0e-5 Torr, bad vac= 4.0e-5 Torr. 

 Saturday, May 26, 2012, 10:44

TGHT is auto ramping up smoothly as the pressure is regulating between 1e-5 to 4 e-5 torr.  (See attachment 2, past 21 hr)

Sunday, May 27, 2012, 12:25  

There could be a power bump  early this morning at 06:30hr, and tripped off the TGHT power supply (see attachment #3).  The computer in the cold lab was found to be off expectedly, so the alarm handler running on that computer was also shut off (*Need a UPS on this computer!)  

Called the ISAC Ops, and  nothing about any power bump around that time was noticed.  

Turned on TGHT p/s and set TGHT at 318A, local at 315A/4.58V.  TGHT has been running for about 10 mins.  Currently vac at 4.2e-7 Torr.  

Sunday, May 27, 2012, 12:35

Initiating TGHT auto ramping... 

 Monday, May 28, 2012, 00:20

TGHT has reached to 600A and will remain at that current for the rest of the night.  The target oven temperature will be measured tomorrow.

See attachment#4 for the striptool over the past 10hr.

 Monday, May 28, 2012, 10:56

TGHT stayed at 600A for about 12 hours.  Pressure gradually came down to 7.6e-7 Torr. (See attachment #5). 

At TGHT=600A, The target boat temperature was measured at 1400C (with the pyrometer), and the Ta-heat shield (1-layer) was at 1050C. [Note: These temperature measurements are very closed to the measurements with an empty LP target (with not heat shield), TGHT @ 600A = 1360C].

Monday, May 28, 2012, 11:04

Due to the water leak from the Evap2 chiller, the system has to be shut off for inspection. 

TGHT was tapped down to 0A.  The target was cooled down for about 20min before the chiller was turned off.

Will continue with the process after the problem is solved...

Nikita Bernier wrote:

Thursday, April 05, 2012, 16:31 Target boat contains 6 BeO pellets : Sample,   Mass (g),   Thickness (mm),   Density (g/cm3) 1   1.2842,    5.406,        1.4647 2   1.2619,    5.150,        1.5108 3   1.2886,    5.316,        1.4946 4   1.2858,    5.310,        1.4931 5   1.3382,    5.520,        1.4948 6   1.3916,    5.650,        1.5187   Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick. **** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****

 Tuesday, May 22, 2012, 16:44

Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.

Nikita Bernier wrote:

John Wong wrote: Nikita Bernier wrote: John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.  Friday, May 18, 2012, 13:15 Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr.  Continue ramping up...   Tuesday, May 22, 2012, 12:02 TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.      Tuesday, May 22, 2012, 12:13 Initiating the cool-down process at 5 A/min. See archive plots of the Target Heater (Attachment 1) and the Tube Heater (Attachment 2).

 Tuesday, May 22, 2012, 15:24

TGHT/TBHT were ramped down to 0A.  The target has cooled for about 45 min.  All pumps and chillers are off.  The chamber has been vented.

John Wong wrote:

Nikita Bernier wrote: John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.  Friday, May 18, 2012, 13:15 Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr.  Continue ramping up...   Tuesday, May 22, 2012, 12:02 TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.

 Tuesday, May 22, 2012, 12:13

Initiating the cool-down process at 5 A/min.

See archive plots of the Target Heater (Attachment 1) and the Tube Heater (Attachment 2).

Nikita Bernier wrote:

John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.

 Friday, May 18, 2012, 13:15

Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr. 

Continue ramping up... 

 Tuesday, May 22, 2012, 12:02

TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.  

John Wong wrote:

Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.

Friday, May 18, 2012, 12:19 

The target is wrapped with only one heat shield.

Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.

John Wong wrote:

Tuesday, May 15, 2012, 17:00 It was found that there were water droplets from the TBHT cooling line.  The joint is leaky.  (see attachment 1)  A message has sent to Rick M.

 Wednesday, May 16, 2012, 14:01

The connector was re-tighten.  The water valve was opened, and no water leaks were found.

 Tuesday, May 15, 2012, 17:03

The tube heater power supply current readback and setpoint are not matching.  Ray Dube checked the power supply and confirmed that it is faulty.  He will replace a functional p/s tomorrow. 

 Friday, May 18, 2012, 13:24

The original p/s was replaced with a new one and there was still a discrepancy between the readback and the setpoint.  After checking with the drawings for the ITE/ITW tube heaters, it was confirmed that the connections for the Evap#2 tube heater control were wrong.  (see attachment 1).  The connections were corrected and the power supply is now operational. 

 Tuesday, May 15, 2012, 17:00

It was found that there were water droplets from the TBHT cooling line.  The joint is leaky.  (see attachment 1) 

A message has sent to Rick M. 

 Tuesday, May 15, 2012, 13:45

It was discovered that one of the insulators that supported the target module broke apart (see Attachment#1).  This might be caused by the heat from the target legs that reflected back from the base to the insulators.  The burnt marks are the evidence.  

A stainless metal sheet is used as the heat shield  (see Attachment #2). 

Tuesday, May 15, 2012, 12:24

The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1. 

This target is going into Evap#2 for re-conditioning.  It is currently being pumped down. 

Thursday, April 05, 2012, 16:31

Target boat contains 6 BeO pellets :

Sample,   Mass (g),   Thickness (mm),   Density (g/cm3)

1   1.2842,    5.406,        1.4647
2   1.2619,    5.150,        1.5108
3   1.2886,    5.316,        1.4946
4   1.2858,    5.310,        1.4931

5   1.3382,    5.520,        1.4948
6   1.3916,    5.650,        1.5187

Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets.

Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick.

**** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****

Tuesday, April 03, 2012, 08:54

Yesterday, a new target boat was sprayed with TaC coating and let dried.

The boat was then installed in the Evap#2 chamber and pumped down to 10-6 Torr before the target heater was turned on.  NOTE: Target boat is not wrapped with Ta-heat shield. 

TGHT auto ramping was initiated at 2.0A/min and max setpoint to 700A.  The voltage was set at 3V; therefore, the current only ramped up to 250A over night.

--> Increased the TGHT voltage to 15A, and continue ramping the TGHT to 700A.  Currently vac at low 2.3e-7 Torr. 

 Tuesday, April 03, 2012, 09:12

The vac is at low 10e-7 as the TGHT is ramping up.  Changing ramping rate from 2A/min to 5A/min. 

Tuesday, April 03, 2012, 12:00  

TGHT reached to 700A. Measured temp @ 1280C. 

Tapped up TGHT to:

800A.  Measured temp @ 1400C. 

850A (local 843A/15.60V). Measured temp @ 1450C.  

900A (local 893A/16.88V).  Measured temp @ 1500C

 Tuesday, April 03, 2012, 14:35:

Try autoramping TGHT to 1000A but voltage has gone up close to the max limit (20V).  TGHT could only go up to ~970A (see attachment 1: TGHT_maxcurrent.jpg).  The heater remained at that current for ~1hr but auto cooling was initiated - at 10A/min.

John Wong wrote:

John Wong wrote: Nikita Bernier wrote:  Thursday, March 29, 2012, 19:17   Target boat contains 3 BeO pellets : Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1    9.06,  1.9713,  1.413 2    9.11,  1.9900,  1.416 3  13.54,  1.9916,  0.956   Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3. The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).        Thursday, March 29, 2012, 22:31: TGHT tripped off a few times over the past hours.  After changing the Good Vac to 2.00e-5 torr and Bad Vac to 3.00e-5 Torr, the target heater are regulating properly and the max pressure is well maintained below 6.5e-5 Torr [Trip point @ 8.0e-5 Torr].  (see attachment#1: parameter.jpg) Friday, March 30, 2012, 23:19   Archive of the target current and vacuum over the past 24 hours.  (see attachment #1: archive_24hr) Saturday, March 31, 2012, 12:12 The organic materials have been burnt off.  The target heater ramping up is no longer restricted by the vacuum limit.  Archive of the target current and vacuum over the past 10 hours. (see attachment #2: TGHT@240A).   Saturday, March 31, 2012, 22:52 TGHT has stayed at 700A/12.37V, local @ 693A/12.43 = Temp @ 1780C.   The striptool shows some out-gassing when TGHT reached to 700A. (see attachment #3 marked with black circle: TGHT@700A.jpg) Increasing TGHT to 750A to see if there is any further reaction...   Sunday, April 01, 2012, 10:24   TGHT was ramped up to 750A, local 730A/13.90V.  The pressure has come down to low 10e-6 but not stable;  Some reaction may be ongoing therefore it's causing the vacuum excursion.  (See attachment #4: TGHT @ 750A).  Notice the current readback is not constant and it's slowly decreasing as the voltage readback is increasing.  There might be some resistant building up. --> Initiating the cool-down process at 2A/min.  Sunday, April 01, 2012, 19:30   TGHT has ramped down to 0A, and the pressure is going down (currently at 7.e-8 Torr) with no excursion.  (see attachment #5: TGHT@0A).  The chamber will be vented tomorrow, and the target materials will be inspected.

 Monday, April 02, 2012, 16:11

After sintering , the 3 BeO pellets have shrunk and feel robust.

The first sample ate through the Ta target boat, shrank a lot and has white and black marks. We suspect the PAM (mostly made of canola oil) to be responsible for the boat damage and the weird sintering process (see John's posts).

Sample 2 is holding well.

Sample 3, which was not washed with acetone, shows some cracks.

Sample,   Thickness (mm),   Mass (g),  Density (g/cm3)

1    -----,  0.6254,  -----

2   5.81,  0.9229,  1.032

3   8.89,  1.1073,  0.809

The average mass before sintering was 1.9843 g. After sintering, 0.8852 g. Thus the average mass loss is 0.9757  (49.0%).

We are starting a new batch of treated powder washed with acetone without PAM.

John Wong wrote:

Nikita Bernier wrote:  Thursday, March 29, 2012, 19:17   Target boat contains 3 BeO pellets : Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1    9.06,  1.9713,  1.413 2    9.11,  1.9900,  1.416 3  13.54,  1.9916,  0.956   Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3. The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).        Thursday, March 29, 2012, 22:31: TGHT tripped off a few times over the past hours.  After changing the Good Vac to 2.00e-5 torr and Bad Vac to 3.00e-5 Torr, the target heater are regulating properly and the max pressure is well maintained below 6.5e-5 Torr [Trip point @ 8.0e-5 Torr].  (see attachment#1: parameter.jpg)

Friday, March 30, 2012, 23:19  

Archive of the target current and vacuum over the past 24 hours.  (see attachment #1: archive_24hr)

Saturday, March 31, 2012, 12:12

The organic materials have been burnt off.  The target heater ramping up is no longer restricted by the vacuum limit. 

Archive of the target current and vacuum over the past 10 hours. (see attachment #2: TGHT@240A). 

 Saturday, March 31, 2012, 22:52

TGHT has stayed at 700A/12.37V, local @ 693A/12.43 = Temp @ 1780C.  

The striptool shows some out-gassing when TGHT reached to 700A. (see attachment #3 marked with black circle: TGHT@700A.jpg)

Increasing TGHT to 750A to see if there is any further reaction...  

Sunday, April 01, 2012, 10:24  

TGHT was ramped up to 750A, local 730A/13.90V.  The pressure has come down to low 10e-6 but not stable;  Some reaction may be ongoing therefore it's causing the vacuum excursion.  (See attachment #4: TGHT @ 750A).  Notice the current readback is not constant and it's slowly decreasing as the voltage readback is increasing.  There might be some resistant building up.

--> Initiating the cool-down process at 2A/min. 

Sunday, April 01, 2012, 19:30  

TGHT has ramped down to 0A, and the pressure is going down (currently at 7.e-8 Torr) with no excursion.  (see attachment #5: TGHT@0A). 

The chamber will be vented tomorrow, and the target materials will be inspected. 

Nikita Bernier wrote:

Thursday, March 29, 2012, 19:17   Target boat contains 3 BeO pellets : Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1    9.06,  1.9713,  1.413 2    9.11,  1.9900,  1.416 3  13.54,  1.9916,  0.956   Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3. The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).

 Thursday, March 29, 2012, 22:31:

TGHT tripped off a few times over the past hours.  After changing the Good Vac to 2.00e-5 torr and Bad Vac to 3.00e-5 Torr, the target heater are regulating properly and the max pressure is well maintained below 6.5e-5 Torr [Trip point @ 8.0e-5 Torr].  (see attachment#1: parameter.jpg)

 Thursday, March 29, 2012, 19:17

Target boat contains 3 BeO pellets :

Sample,   Thickness (mm),   Mass (g),  Density (g/cm3)

1    9.06,  1.9713,  1.413

2    9.11,  1.9900,  1.419

3  13.54,  1.9916,  0.956

Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3.

The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased.

Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).