# Presentation: 072531

**Noise Studies in the Calorimeter**

**Robert Zitoun**
**Stony Brook**
** ****Collaboration Meeting**
**October 10, 2003**

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Evidence for Bad Data (1)

-  	Ring of fire
- ADC noise

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Evidence for Bad Data (2)

-  		Yuri’s jets
- MET x-y

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

**Noise Study**
- Mike Arov, Dan Edmunds, Leslie Groer, Marvin Johnson, Dean Schamberger, RZ
- + colleagues from SMT, CFT, MUON, FPD
- + many techs

- Occasional noises: ring of fire
- Permanent noises

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Ring of Fire

**Ring of Fire**

- Outermost EM rings in EC fired+ accompanied by HAD noise in ICR
- Already seen in run 1:
- temperature monitoring system
- special ring shaped HV distribution
- Occurs when the welder in DAB3 is triggered
- In the 2 MHz region
- Sudden burst of CAL triggers

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Ring of Fire (2)

- Welder noise enters the cryostat  on temperature monitoring cables
- Disappears when cables are disconnected (safe!)
- Remaining questions:
- how is this noise getting to these cables?
- does noise get also through purity monitoring cables?
- other unidentified sources?

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Lines identified with a spectrum analyzer in May

14.3 MHz (=RF/4)
10 MHz

		Find source(s)
		Find path(s)
		Fix

Note: those noises may not be harmful but other occasional bad noise may follow the same path

- Lines identified with a spectrum analyzer in May
- 14.3 MHz (=RF/4)
- 10 MHz
- 		Find source(s)
- 		Find path(s)
- 		Fix
- Note: those noises may not be harmful but other occasional bad noise may follow the same path

**Hunting for Permanent Noises**

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## RF/4 Noise

- Injected charge depends on the bunch number
- Out of phase after a full turn
- Produce coherent effect over the detector
- how large?
- ? Linked with observed coherent noise(Bawo Daibo + Leslie Groer)

- RF/4 not multiple
-  of
- 1 turn = RF/7×153

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## RF/4 Noise (2)

**RF/4 Noise (2)**

- Clearly correlated with MUON chambers
- on/off
- dropped when opening the central toroid
- clear radiation from the chambers (Stefan Grünendahl)
- “Unstable”
- disappears (sometimes) if chambers are in synch
- smaller or larger with smaller number of chambers
- MUON experts think it goes through power lines, then to ground
- CAL experts think of capacitive coupling
- MUON chambers right above CAL preamp boxes
- Difficult to shield
- Studies would need to close/open central Iron at will

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## 10 MHz Noise

- Appeared when SMT sequencers started
- Little contribution from CFT
- No 10 MHz in the boards, but linked with DØ clock
- Due to the superbunch structure (53 ticks, 12 bunches)
- Fourier transform of bunch signal produces 2 strong lines @
- 70 *f*tick = 10.020 MHz & 71 *f*tick = 10.162 MHz
-  agrees perfectly with high-res spectrum analyzer measurement

*bunch + signal*

*signal without bunch*

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## 10 MHz Noise (2)

- How is it getting to CAL?
- Mostly in EC
- When ECN moved out, decreased in ECN but also partly in ECS
- When ECS moved out, decreased but not clear what happened
- Radio tuned on 10.16 MHz (“WSMT”) showed emission from
- 	cables bringing clock from sequencers to the interface boards
- 	front bottom of interface board crates
- 	a few SMT differential coaxials

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## 10 MHz Noise (3)

- Favorite hypothesis: noise comes in the cal by the ground
- 10 MHz is part of a synchronous noise 	bunch signal should just move pedestal
- 		no large effect expected (except 1st bunches?)
- if noise path found, unidentified noises may disappear

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Next Week Plans

**Next Week Plans**

- Take benefit of Monday power outage to find the welder noise path
- disconnect D0 detector (including MCH) from safety ground (including SCL cables, FPD, phone lines, ... all line violating single point safety ground)
- look for unknown contact visually (visible light)
- set a 100 amp. current generator between cal and ground and look for IR light (touch for heat)
- hazardous, but already (successfully) done in Run I
- 	slow increase, voltage < 0.5V
- Continue studies to understand how important are RF/4 and 10 MHz noises

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## 
Not only noise
Also hot cells, electronic failure, ...

2 (successful) examples

- Not only noise
- Also hot cells, electronic failure, ...
- 2 (successful) examples

**Hunt for Other Bad Behavior**

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Jet Distribution in MHT30 Triggers

- Slava Shary (Orsay)
- made list of hot cells found in zero bias events
- cells dropped from reco

- after

- Turns a bad run into a good one!
- Is it the whole story?

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Crate 8 (energy sharing) problem
Tower 2 (tower not read, another one read twice)
Both found from electronics studies

Plot by J. Gardner
Shows tower 2 + crate 8
Pointed to swapped cables

Shows other problems
	How long to understand/fix them?

- Tower 2 (tower not read, another one read twice)
- Both found from electronics studies
- Plot by J. Gardner
- Shows tower 2 + crate 8
- Pointed to swapped cables
- Shows other problems
- 	How long to understand/fix them?

**Readout Problems**

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003

## Conclusion

- Noise
- Progress in its understanding, but still much to understand
- Difficult to know how much fixes will improve the data
- Hot cells
- Much to be gained in correcting the data
- Issues not yet addressed (when?)
- Yuri’s jets
- ADC noise
- Real need of manpower

- R. Zitoun, Stony Brook                 Collaboration Meeting

- October 10, 2003