Studies of EMCal block densities & dimensions Anabel Hernandez, - - PowerPoint PPT Presentation

• C. Riedl (UIUC) May 8, 2019

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Studies of EMCal block densities & dimensions

Anabel Hernandez, Caroline Riedl, Tim Rinn, Anne Sickles, 
 Eric Thorsland, Xiaoning Wang, and Adam Wehe (UIUC)


May 8, 2019

• August 2018 drop in density
• Correlations?

• Block dimensions

• C. Riedl (UIUC) May 8, 2019

Block density vs. time

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W date sorted 8.5 9.0 9.5 10.0 9/1/2018 11/1/2018 1/1/2019 3/1/2019 Avg block density [g/cm3] THP Sector 0 Avg block density [g/cm3] HCS Sector 0 0.85* Avg tap density THP [g/cm3] S0

Block Density Sector 0

W date sorted 8.5 9.0 9.5 10.0 4/5/2019 4/7/2019 4/9/2019 4/11/2019 4/13/2019 4/15/2019 Avg block density [g/cm3] THP Sector 1-12 Avg block density [g/cm3] HCS Sector 1-12 0.85* Avg tap density HCS [g/cm3] S0

Block Density Sector 1-12

• Left: drop in THP block density in October 2018 (blue curve), while tap density stayed ~ constant
• Recovering towards the end of March? (also slightly higher tap density due to different buckets)
• HCS block density was higher in 2018 than in 2019 using very similar tungsten batches
• Right: overall HCS block density is lower, as ~ expected from lower HCS tap density

• C. Riedl (UIUC) May 8, 2019

Twin blocks March 2019: THP vs. HCS

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• Lower tap density of HCS as compared to THP considered to be the main reason

for the overall lower density of HCS blocks.

• Set of twin blocks potted in March side-by-side using 

• block 9, DBN 353 THP 

• block 9, DBN 354 HCS 


In both cases, no more powder could have been added: both blocks were filled up to the top edge of the mold windows.

• Ratio of block densities HCS / THP = 0.91
• Ratio of tap densities HCS / THP = 0.93
• Difference in these ratios is attributed to the fact that the final block compound also

contains materials of lower density than tungsten (fibers, brass and epoxy).

• C. Riedl (UIUC) May 8, 2019

What drives the block density?

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W date sorted 8.5 9.0 9.5 10.0 9/1/2018 11/1/2018 1/1/2019 3/1/2019 Avg block density [g/cm3] THP Sector 0 Avg block density [g/cm3] HCS Sector 0 0.85* Avg tap density THP [g/cm3] S0

Block Density Sector 0

W date sorted Avg relative tungsten weight 0.95 0.975 1 1.025 1.05 9/1/2018 11/1/2018 1/1/2019 3/1/2019

Avg relative filled W weight vs. W date (Sector 0)

• The more tungsten weight is

filled, the higher the block density (in general)

• Relative weight = actual filled

mass [g] / average mass [g] for that block design of S0

Relative tungsten weight block density [g/cm3] 8.00 8.50 9.00 9.50 10.00 0.85 0.9 0.95 1 1.05 1.1 1.15

Block density vs. relative tungsten weight (S0)

• C. Riedl (UIUC) May 8, 2019

Why does the block density drop? (I)

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W date sorted 8.5 9.0 9.5 10.0 9/1/2018 11/1/2018 1/1/2019 3/1/2019 Avg block density [g/cm3] THP Sector 0 Avg block density [g/cm3] HCS Sector 0 0.85* Avg tap density THP [g/cm3] S0

Block Density Sector 0

• Block density not 1:1 related to

tap density

• Do different W fillers

compactify differently? Not

• really. Drop affects them all.

Block density S0 tap density S0 10.8 11.0 11.2 11.4 8.50 8.75 9.00 9.25 9.50 9.75

Tap density S0 vs. Block density S0

8.75 9.00 9.25 9.50 9.75 10.00 7/5/2018 7/6/2018 7/9/2018 7/10/2018 7/13/2018 8/2/2018 8/6/2018 8/22/2018 8/30/2018 9/26/2018 10/8/2018 11/19/201 2/14/2019 2/18/2019 2/21/2019 2/25/2019 3/1/2019 3/5/2019 3/7/2019 3/14/2019 3/25/2019 3/27/2019 3/28/2019 Avg block density [g/cm3] THP Sector 0 Avg block density [g/cm3] HCS Sector 0 0.85* Avg tap density THP [g/cm3] S0

• avg. ET
• avg. SA
• avg. MA
• avg. SS

Block Density Sector 0

• C. Riedl (UIUC) May 8, 2019

Block density vs. time and block count

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W date sorted 8.5 9.0 9.5 10.0 9/1/2018 11/1/2018 1/1/2019 3/1/2019 Avg block density [g/cm3] THP Sector 0 Avg block density [g/cm3] HCS Sector 0 0.85* Avg tap density THP [g/cm3] S0

Block Density Sector 0

W date sorted 5 10 15 20 7/5/2018 7/6/2018 7/9/2018 7/10/201 7/13/201 8/2/2018 8/6/2018 8/22/201 8/30/201 9/26/201 10/8/201 11/19/20 2/14/201 2/18/201 2/21/201 2/25/201 3/1/2019 3/5/2019 3/7/2019 3/14/201 3/25/201 3/27/201 3/28/201 count THP count HCS

Sector 0: block count vs. time

• At the time of the

drop, many blocks were potted

• C. Riedl (UIUC) May 8, 2019

Why does the block density drop? (II)

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W date sorted 8.5 9.0 9.5 10.0 9/1/2018 11/1/2018 1/1/2019 3/1/2019 Avg block density [g/cm3] THP Sector 0 Avg block density [g/cm3] HCS Sector 0 0.85* Avg tap density THP [g/cm3] S0

Block Density Sector 0

• Drop is

between early October and mid March

• Environment?
• It is warm and

humid in the high-bay area where the W is stored, cool and dry in summer

• Does the

ambient humidity affect the block density?

• So far best

guess… Avg temperature [F] per hour heat ON in high bay

• C. Riedl (UIUC) May 8, 2019

Why does the block density drop? (III)

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• Big shaker table introduced in December 2018, cannot explain drop in block densities
• Different levels and methods of densification are being tested, no conclusive results yet
• The shorter the epoxy pulling out time, the higher the block density - with outliers.

• C. Riedl (UIUC) May 8, 2019

Quality of blocks potted with HCS in 2019 and undersized blocks

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• All Sector 1 blocks produced with HCS in 2019 (so far ~20) need touch-ups after they come out
• f the mold, longer epoxy time.
• Potting procedure had been optimized for THP in 2018.

• All blocks come out slightly undersized. This had already been the case for THP in 2018/2019

(table), which is attributed to (intentionally) undersized molds.

• However HCS blocks shrink more than THP 


blocks, which is why the undersizing effect is 
 pronounced more in HCS.

• C. Riedl (UIUC) May 8, 2019

Blocks potted with HCS in 2019

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